From 88c14c25485c16598f1be83439283244ce703477 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Tue, 13 Jan 2026 20:33:07 +0200 Subject: [PATCH 1/9] add : basic csv writer --- .idea/.gitignore | 10 ++ .idea/encodings.xml | 7 ++ .idea/misc.xml | 12 +++ .idea/vcs.xml | 6 ++ persons.csv | 11 ++ .../org/writer/ArrayIsEmptyException.java | 6 ++ src/main/java/org/writer/CsvFileWriter.java | 100 ++++++++++++++++++ src/main/java/org/writer/Main.java | 23 +++- src/main/java/org/writer/model/Person.java | 89 ++++++++++++++++ src/main/java/org/writer/model/Student.java | 56 ++++++++++ students.csv | 11 ++ 11 files changed, 330 insertions(+), 1 deletion(-) create mode 100644 .idea/.gitignore create mode 100644 .idea/encodings.xml create mode 100644 .idea/misc.xml create mode 100644 .idea/vcs.xml create mode 100644 persons.csv create mode 100644 src/main/java/org/writer/ArrayIsEmptyException.java create mode 100644 src/main/java/org/writer/CsvFileWriter.java create mode 100644 students.csv diff --git a/.idea/.gitignore b/.idea/.gitignore new file mode 100644 index 0000000..ab1f416 --- /dev/null +++ b/.idea/.gitignore @@ -0,0 +1,10 @@ +# Default ignored files +/shelf/ +/workspace.xml +# Ignored default folder with query files +/queries/ +# Datasource local storage ignored files +/dataSources/ +/dataSources.local.xml +# Editor-based HTTP Client requests +/httpRequests/ diff --git a/.idea/encodings.xml b/.idea/encodings.xml new file mode 100644 index 0000000..aa00ffa --- /dev/null +++ b/.idea/encodings.xml @@ -0,0 +1,7 @@ + + + + + + + \ No newline at end of file diff --git a/.idea/misc.xml b/.idea/misc.xml new file mode 100644 index 0000000..9dc782b --- /dev/null +++ b/.idea/misc.xml @@ -0,0 +1,12 @@ + + + + + + + + \ No newline at end of file diff --git a/.idea/vcs.xml b/.idea/vcs.xml new file mode 100644 index 0000000..35eb1dd --- /dev/null +++ b/.idea/vcs.xml @@ -0,0 +1,6 @@ + + + + + + \ No newline at end of file diff --git a/persons.csv b/persons.csv new file mode 100644 index 0000000..a072cec --- /dev/null +++ b/persons.csv @@ -0,0 +1,11 @@ +firstName,lastName,dayOfBirth,monthOfBirth,yearOfBirth +Alex,Ivanov,12,JANUARY,1995 +Maria,Petrova,3,FEBRUARY,1998 +John,Smith,21,MARCH,1990 +Elena,Popescu,9,APRIL,1997 +Victor,Radu,30,MAY,1993 +Anna,Kowalski,14,JUNE,2000 +Daniel,Novak,7,JULY,1992 +Sofia,Marin,18,AUGUST,1996 +Mihai,Dumitru,25,SEPTEMBER,1994 +Laura,Bianchi,2,OCTOBER,1999 diff --git a/src/main/java/org/writer/ArrayIsEmptyException.java b/src/main/java/org/writer/ArrayIsEmptyException.java new file mode 100644 index 0000000..8888eda --- /dev/null +++ b/src/main/java/org/writer/ArrayIsEmptyException.java @@ -0,0 +1,6 @@ +package org.writer; + +public class ArrayIsEmptyException extends RuntimeException { + public ArrayIsEmptyException(String s) { + } +} diff --git a/src/main/java/org/writer/CsvFileWriter.java b/src/main/java/org/writer/CsvFileWriter.java new file mode 100644 index 0000000..71b91a7 --- /dev/null +++ b/src/main/java/org/writer/CsvFileWriter.java @@ -0,0 +1,100 @@ +package org.writer; + +import java.io.*; +import java.lang.reflect.Field; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.StandardOpenOption; +import java.util.Arrays; +import java.util.List; +import java.util.stream.Collectors; + +public class CsvFileWriter implements Writable { + + /* + * todo: дописать метод и отрефакторить в цепочку обязанностей + * */ + @Override + public void writeToFile(List data, String fileName) { + if (data.isEmpty()) { + throw new ArrayIsEmptyException("Fill array with data!"); + } + + Path path = Path.of(fileName); + boolean fileExists; + + Class dataTypeClass = data.get(0).getClass(); + + String header = Arrays.stream(dataTypeClass.getDeclaredFields()) + .map(Field::getName) + .collect(Collectors.joining(",")); + + try { + fileExists = Files.exists(path) && Files.size(path) > 0; + } catch (IOException e) { + throw new RuntimeException(e); + } + if (fileExists) { + validateHeader(path, header); + } + + try (BufferedWriter writer = Files.newBufferedWriter( + path, + StandardOpenOption.CREATE, + StandardOpenOption.APPEND + )) { + if (!fileExists) { + writer.write(header); + writer.newLine(); + } + data.stream().map(element -> { + Class clazz = element.getClass(); + return Arrays.stream(clazz.getDeclaredFields()) + .map(field -> { + try { + field.setAccessible(true); + return escapeCsv(field.get(element).toString()); + } catch (IllegalAccessException e) { + throw new RuntimeException(e); + } + }).collect(Collectors.joining(",")); + } + ).forEach(csvRow -> { + try { + writer.write(csvRow); + writer.newLine(); + } catch (IOException e) { + throw new RuntimeException(e); + } + }); + + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + private String escapeCsv(String value) { + if (value.contains(",") || value.contains("\"") || value.contains("\n")) { + value = value.replace("\"", "\"\""); + return "\"" + value + "\""; + } + return value; + } + + private void validateHeader(Path path, String existingHeader) { + try (BufferedReader reader = Files.newBufferedReader(path)) { + String header = reader.readLine(); + boolean isHeaderEquals = header.equals(existingHeader); + + if (!isHeaderEquals) { + throw new IllegalStateException( + "CSV header mismatch. Expected: " + + header + ", actual: " + existingHeader + ); + } + } catch (IOException e) { + throw new RuntimeException(e); + } + } + +} diff --git a/src/main/java/org/writer/Main.java b/src/main/java/org/writer/Main.java index 40e8213..bc7614e 100644 --- a/src/main/java/org/writer/Main.java +++ b/src/main/java/org/writer/Main.java @@ -1,7 +1,28 @@ package org.writer; +import org.writer.model.Months; +import org.writer.model.Person; +import org.writer.model.Student; + +import java.util.List; + public class Main { public static void main(String[] args) { - System.out.println("Hello world!"); + String peopleFileName = "persons.csv"; + String studentshipName = "students.csv"; + + List personList = Person.getTestList(); + List studentList = Student.getTestList(); + + CsvFileWriter csvFileWriter = new CsvFileWriter(); + + csvFileWriter.writeToFile(personList, peopleFileName); + csvFileWriter.writeToFile(studentList, studentshipName); + + + } + + { + } } \ No newline at end of file diff --git a/src/main/java/org/writer/model/Person.java b/src/main/java/org/writer/model/Person.java index ba8576b..9db9959 100644 --- a/src/main/java/org/writer/model/Person.java +++ b/src/main/java/org/writer/model/Person.java @@ -4,6 +4,8 @@ import lombok.Builder; import lombok.Data; +import java.util.List; + @Data @Builder @AllArgsConstructor @@ -19,4 +21,91 @@ public class Person { private int yearOfBirth; + + + public static List getTestList(){ + return List.of( + Person.builder() + .firstName("Alex") + .lastName("Ivanov") + .dayOfBirth(12) + .monthOfBirth(Months.JANUARY) + .yearOfBirth(1995) + .build(), + + Person.builder() + .firstName("Maria") + .lastName("Petrova") + .dayOfBirth(3) + .monthOfBirth(Months.FEBRUARY) + .yearOfBirth(1998) + .build(), + + Person.builder() + .firstName("John") + .lastName("Smith") + .dayOfBirth(21) + .monthOfBirth(Months.MARCH) + .yearOfBirth(1990) + .build(), + + Person.builder() + .firstName("Elena") + .lastName("Popescu") + .dayOfBirth(9) + .monthOfBirth(Months.APRIL) + .yearOfBirth(1997) + .build(), + + Person.builder() + .firstName("Victor") + .lastName("Radu") + .dayOfBirth(30) + .monthOfBirth(Months.MAY) + .yearOfBirth(1993) + .build(), + + Person.builder() + .firstName("Anna") + .lastName("Kowalski") + .dayOfBirth(14) + .monthOfBirth(Months.JUNE) + .yearOfBirth(2000) + .build(), + + Person.builder() + .firstName("Daniel") + .lastName("Novak") + .dayOfBirth(7) + .monthOfBirth(Months.JULY) + .yearOfBirth(1992) + .build(), + + Person.builder() + .firstName("Sofia") + .lastName("Marin") + .dayOfBirth(18) + .monthOfBirth(Months.AUGUST) + .yearOfBirth(1996) + .build(), + + Person.builder() + .firstName("Mihai") + .lastName("Dumitru") + .dayOfBirth(25) + .monthOfBirth(Months.SEPTEMBER) + .yearOfBirth(1994) + .build(), + + Person.builder() + .firstName("Laura") + .lastName("Bianchi") + .dayOfBirth(2) + .monthOfBirth(Months.OCTOBER) + .yearOfBirth(1999) + .build() + ); + + } + } diff --git a/src/main/java/org/writer/model/Student.java b/src/main/java/org/writer/model/Student.java index 2b549c4..1133b21 100644 --- a/src/main/java/org/writer/model/Student.java +++ b/src/main/java/org/writer/model/Student.java @@ -14,4 +14,60 @@ public class Student { private String name; private List score; + + + public static List getTestList(){ + return List.of( + Student.builder() + .name("Alex") + .score(List.of("A", "B", "A")) + .build(), + + Student.builder() + .name("Maria") + .score(List.of("A", "A", "A")) + .build(), + + Student.builder() + .name("John") + .score(List.of("B", "C", "B")) + .build(), + + Student.builder() + .name("Elena") + .score(List.of("A", "B", "C")) + .build(), + + Student.builder() + .name("Victor") + .score(List.of("B", "B", "B")) + .build(), + + Student.builder() + .name("Anna") + .score(List.of("A", "C", "B")) + .build(), + + Student.builder() + .name("Daniel") + .score(List.of("C", "B", "A")) + .build(), + + Student.builder() + .name("Sofia") + .score(List.of("A", "A", "B")) + .build(), + + Student.builder() + .name("Mihai") + .score(List.of("B", "C", "C")) + .build(), + + Student.builder() + .name("Laura") + .score(List.of("A", "B", "A")) + .build() + ); + + } } \ No newline at end of file diff --git a/students.csv b/students.csv new file mode 100644 index 0000000..bd5792c --- /dev/null +++ b/students.csv @@ -0,0 +1,11 @@ +name,score +Alex,"[A, B, A]" +Maria,"[A, A, A]" +John,"[B, C, B]" +Elena,"[A, B, C]" +Victor,"[B, B, B]" +Anna,"[A, C, B]" +Daniel,"[C, B, A]" +Sofia,"[A, A, B]" +Mihai,"[B, C, C]" +Laura,"[A, B, A]" From ad1c4120269572406e828a4a49c93b632e08fe84 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Tue, 13 Jan 2026 21:15:19 +0200 Subject: [PATCH 2/9] ref: writer refactor of responsibility --- persons.csv | 22 +++--- src/main/java/org/writer/CsvFileWriter.java | 88 +++++++++++++-------- 2 files changed, 65 insertions(+), 45 deletions(-) diff --git a/persons.csv b/persons.csv index a072cec..0d71db3 100644 --- a/persons.csv +++ b/persons.csv @@ -1,11 +1,11 @@ -firstName,lastName,dayOfBirth,monthOfBirth,yearOfBirth -Alex,Ivanov,12,JANUARY,1995 -Maria,Petrova,3,FEBRUARY,1998 -John,Smith,21,MARCH,1990 -Elena,Popescu,9,APRIL,1997 -Victor,Radu,30,MAY,1993 -Anna,Kowalski,14,JUNE,2000 -Daniel,Novak,7,JULY,1992 -Sofia,Marin,18,AUGUST,1996 -Mihai,Dumitru,25,SEPTEMBER,1994 -Laura,Bianchi,2,OCTOBER,1999 +dayOfBirth,firstName,lastName,monthOfBirth,yearOfBirth +12,Alex,Ivanov,JANUARY,1995 +3,Maria,Petrova,FEBRUARY,1998 +21,John,Smith,MARCH,1990 +9,Elena,Popescu,APRIL,1997 +30,Victor,Radu,MAY,1993 +14,Anna,Kowalski,JUNE,2000 +7,Daniel,Novak,JULY,1992 +18,Sofia,Marin,AUGUST,1996 +25,Mihai,Dumitru,SEPTEMBER,1994 +2,Laura,Bianchi,OCTOBER,1999 diff --git a/src/main/java/org/writer/CsvFileWriter.java b/src/main/java/org/writer/CsvFileWriter.java index 71b91a7..97eda5e 100644 --- a/src/main/java/org/writer/CsvFileWriter.java +++ b/src/main/java/org/writer/CsvFileWriter.java @@ -6,6 +6,7 @@ import java.nio.file.Path; import java.nio.file.StandardOpenOption; import java.util.Arrays; +import java.util.Comparator; import java.util.List; import java.util.stream.Collectors; @@ -16,24 +17,17 @@ public class CsvFileWriter implements Writable { * */ @Override public void writeToFile(List data, String fileName) { - if (data.isEmpty()) { - throw new ArrayIsEmptyException("Fill array with data!"); - } + validateData(data); Path path = Path.of(fileName); - boolean fileExists; - - Class dataTypeClass = data.get(0).getClass(); + Class clazz = data.get(0).getClass(); - String header = Arrays.stream(dataTypeClass.getDeclaredFields()) + Field[] fields = getAccessibleFields(clazz); + String header = Arrays.stream(fields) .map(Field::getName) .collect(Collectors.joining(",")); - try { - fileExists = Files.exists(path) && Files.size(path) > 0; - } catch (IOException e) { - throw new RuntimeException(e); - } + boolean fileExists = isFileExists(path); if (fileExists) { validateHeader(path, header); } @@ -44,36 +38,49 @@ public void writeToFile(List data, String fileName) { StandardOpenOption.APPEND )) { if (!fileExists) { - writer.write(header); - writer.newLine(); + writeCsvRow(writer, header); } - data.stream().map(element -> { - Class clazz = element.getClass(); - return Arrays.stream(clazz.getDeclaredFields()) - .map(field -> { - try { - field.setAccessible(true); - return escapeCsv(field.get(element).toString()); - } catch (IllegalAccessException e) { - throw new RuntimeException(e); - } - }).collect(Collectors.joining(",")); + for (Object element : data) { + String csvRow = joinFieldsToCsvRow(element, fields); + writeCsvRow(writer, csvRow); + } + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + private String joinFieldsToCsvRow(Object objectToRow, Field[]fields){ + return Arrays.stream(fields) + .map(field -> { + try { + Object value = field.get(objectToRow); + return escapeCsv(value == null ? "" : value.toString()); + } catch (IllegalAccessException e) { + throw new RuntimeException(e); } - ).forEach(csvRow -> { - try { - writer.write(csvRow); - writer.newLine(); - } catch (IOException e) { - throw new RuntimeException(e); - } - }); + }) + .collect(Collectors.joining(",")); + } + private Field[] getAccessibleFields(Class clazz){ + Field[] fields = clazz.getDeclaredFields(); + Arrays.sort(fields, Comparator.comparing(Field::getName)); + for (Field field : fields) { + field.setAccessible(true); + } + return fields; + } + private void writeCsvRow(BufferedWriter writer, String csvRow) { + try { + writer.write(csvRow); + writer.newLine(); } catch (IOException e) { throw new RuntimeException(e); } } private String escapeCsv(String value) { + if (value.contains(",") || value.contains("\"") || value.contains("\n")) { value = value.replace("\"", "\"\""); return "\"" + value + "\""; @@ -81,6 +88,20 @@ private String escapeCsv(String value) { return value; } + private boolean isFileExists(Path path) { + try { + return Files.exists(path) && Files.size(path) > 0; + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + private void validateData(List data) { + if (data.isEmpty()) { + throw new ArrayIsEmptyException("Fill array with data!"); + } + } + private void validateHeader(Path path, String existingHeader) { try (BufferedReader reader = Files.newBufferedReader(path)) { String header = reader.readLine(); @@ -96,5 +117,4 @@ private void validateHeader(Path path, String existingHeader) { throw new RuntimeException(e); } } - } From 9eba38d091f3b32c3225cbbf00a5c8ecb33426b9 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Wed, 14 Jan 2026 15:26:11 +0200 Subject: [PATCH 3/9] ref: ref writer, add: javadoc --- src/main/java/org/writer/CsvContext.java | 29 ++++ src/main/java/org/writer/CsvFileWriter.java | 154 +++++++++++++++----- src/main/java/org/writer/Writable.java | 2 +- 3 files changed, 146 insertions(+), 39 deletions(-) create mode 100644 src/main/java/org/writer/CsvContext.java diff --git a/src/main/java/org/writer/CsvContext.java b/src/main/java/org/writer/CsvContext.java new file mode 100644 index 0000000..aea0a9c --- /dev/null +++ b/src/main/java/org/writer/CsvContext.java @@ -0,0 +1,29 @@ +package org.writer; + +import lombok.Getter; +import lombok.Setter; + +import java.io.BufferedWriter; +import java.lang.reflect.Field; +import java.nio.file.Path; +import java.util.List; + +@Getter +@Setter +public class CsvContext { + public List data; + Path path; + boolean isFileExists; + Class clazz; + Field[] fields; + String header; + BufferedWriter writer; + + public CsvContext(List data, String fileName) { + this.data = data; + this.path = Path.of(fileName); + + } + + +} diff --git a/src/main/java/org/writer/CsvFileWriter.java b/src/main/java/org/writer/CsvFileWriter.java index 97eda5e..84e8d67 100644 --- a/src/main/java/org/writer/CsvFileWriter.java +++ b/src/main/java/org/writer/CsvFileWriter.java @@ -10,38 +10,41 @@ import java.util.List; import java.util.stream.Collectors; -public class CsvFileWriter implements Writable { - /* - * todo: дописать метод и отрефакторить в цепочку обязанностей - * */ +/** + * Writes Java objects to a CSV file using reflection. + * + *

The writer automatically generates a CSV header based on + * the object's fields and ensures header consistency when appending data.

+ * + *

This class is not thread-safe.

+ */ +public class CsvFileWriter implements Writable { + /*** + * Writes a list of objects to a CSV file + * + * @param data list of objects to be written; must not be empty + * @param fileName name of file where data will be written + */ @Override public void writeToFile(List data, String fileName) { - validateData(data); - - Path path = Path.of(fileName); - Class clazz = data.get(0).getClass(); + CsvContext csvContext = new CsvContext(data, fileName); - Field[] fields = getAccessibleFields(clazz); - String header = Arrays.stream(fields) - .map(Field::getName) - .collect(Collectors.joining(",")); + validateData(csvContext); + resolveMetadata(csvContext); + checkFile(csvContext); - boolean fileExists = isFileExists(path); - if (fileExists) { - validateHeader(path, header); - } try (BufferedWriter writer = Files.newBufferedWriter( - path, + csvContext.getPath(), StandardOpenOption.CREATE, StandardOpenOption.APPEND )) { - if (!fileExists) { - writeCsvRow(writer, header); + if (!csvContext.isFileExists()) { + writeCsvRow(writer, csvContext.getHeader()); } - for (Object element : data) { - String csvRow = joinFieldsToCsvRow(element, fields); + for (Object element : csvContext.getData()) { + String csvRow = joinFieldsToCsvRow(element, csvContext.getFields()); writeCsvRow(writer, csvRow); } } catch (IOException e) { @@ -49,27 +52,36 @@ public void writeToFile(List data, String fileName) { } } - private String joinFieldsToCsvRow(Object objectToRow, Field[]fields){ + /*** + * Joins field values into a CSV string + * @param objectToRow the object whose data we will connect + * @param fields the object whose data we will connect + * @return joined row for CSV + */ + private String joinFieldsToCsvRow(Object objectToRow, Field[] fields) { return Arrays.stream(fields) .map(field -> { try { Object value = field.get(objectToRow); return escapeCsv(value == null ? "" : value.toString()); } catch (IllegalAccessException e) { - throw new RuntimeException(e); + throw new RuntimeException("Access was not permitted ", e); } }) .collect(Collectors.joining(",")); } - private Field[] getAccessibleFields(Class clazz){ - Field[] fields = clazz.getDeclaredFields(); - Arrays.sort(fields, Comparator.comparing(Field::getName)); - for (Field field : fields) { - field.setAccessible(true); - } - return fields; - } + + /** + * Writes a single CSV row to the given writer. + * + *

The method appends the row followed by a line separator.

+ * + * @param writer the {@link BufferedWriter} used to write data to the CSV file + * @param csvRow the CSV-formatted row to write + * + * @throws RuntimeException if an I/O error occurs while writing the row + */ private void writeCsvRow(BufferedWriter writer, String csvRow) { try { writer.write(csvRow); @@ -79,6 +91,16 @@ private void writeCsvRow(BufferedWriter writer, String csvRow) { } } + /** + * Escapes a value according to CSV format rules. + * + *

If the value contains a comma, double quote, or line break, + * it is wrapped in double quotes and internal quotes are escaped + * by doubling them.

+ * + * @param value the raw value to escape + * @return a CSV-safe representation of the value + */ private String escapeCsv(String value) { if (value.contains(",") || value.contains("\"") || value.contains("\n")) { @@ -88,33 +110,89 @@ private String escapeCsv(String value) { return value; } - private boolean isFileExists(Path path) { + /** + * Checks whether the target CSV file exists and validates its header if present. + * + *

If the file exists and is not empty, the method verifies that the existing + * CSV header matches the header generated from the current data structure.

+ * + * @param context the CSV processing context containing file path and header + * + * @throws IllegalStateException if the existing CSV header does not match + * @throws RuntimeException if an I/O error occurs while accessing the file + */ + private void checkFile(CsvContext context) { try { - return Files.exists(path) && Files.size(path) > 0; + boolean isFileExists = Files.exists(context.getPath()) && Files.size(context.getPath()) > 0; + context.setFileExists(isFileExists); + if (isFileExists){ + validateHeader(context.getPath(), context.getHeader()); + } } catch (IOException e) { throw new RuntimeException(e); } } - private void validateData(List data) { - if (data.isEmpty()) { + /** + * Validates that the CSV context contains data to be written. + * + * @param context the CSV processing context + * + * @throws ArrayIsEmptyException if the data list is empty + */ + private void validateData(CsvContext context) { + if (context.getData().isEmpty()) { throw new ArrayIsEmptyException("Fill array with data!"); } } - private void validateHeader(Path path, String existingHeader) { + /** + * Validates that the header of an existing CSV file matches the expected header. + * + * @param path the path to the existing CSV file + * @param dataHeader the expected CSV header generated from the data structure + * + * @throws IllegalStateException if the headers do not match + * @throws RuntimeException if an I/O error occurs while reading the file + */ + + private void validateHeader(Path path, String dataHeader) { try (BufferedReader reader = Files.newBufferedReader(path)) { String header = reader.readLine(); - boolean isHeaderEquals = header.equals(existingHeader); + boolean isHeaderEquals = header.equals(dataHeader); if (!isHeaderEquals) { throw new IllegalStateException( "CSV header mismatch. Expected: " - + header + ", actual: " + existingHeader + + header + ", actual: " + dataHeader ); } } catch (IOException e) { throw new RuntimeException(e); } } + + /** + * Resolves reflection metadata required for CSV serialization. + * + *

The method determines the class of the data elements, extracts + * declared fields, sorts them in a deterministic order, and prepares + * them for access. It also generates a CSV header based on the field names.

+ * + * @param context the CSV processing context to populate with metadata + */ + private void resolveMetadata(CsvContext context) { + context.clazz = context.data.get(0).getClass(); + + Field[] fields = context.clazz.getDeclaredFields(); + Arrays.sort(fields, Comparator.comparing(Field::getName)); + for (Field f : fields) { + f.setAccessible(true); + } + + context.fields = fields; + context.header = Arrays.stream(fields) + .map(Field::getName) + .collect(Collectors.joining(",")); + } } diff --git a/src/main/java/org/writer/Writable.java b/src/main/java/org/writer/Writable.java index 9f60c45..03b045a 100644 --- a/src/main/java/org/writer/Writable.java +++ b/src/main/java/org/writer/Writable.java @@ -2,7 +2,7 @@ import java.util.List; -public interface Writable { +public interface Writable{ void writeToFile(List data, String fileName); From 49e651cc669da6dccb08ea181ef3abad795db343 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Wed, 14 Jan 2026 15:33:55 +0200 Subject: [PATCH 4/9] ref: ref context access level and javadoc --- persons.csv | 10 +++++ src/main/java/org/writer/CsvContext.java | 13 +++--- src/main/java/org/writer/CsvFileWriter.java | 45 +++++++++++---------- students.csv | 10 +++++ 4 files changed, 50 insertions(+), 28 deletions(-) diff --git a/persons.csv b/persons.csv index 0d71db3..831c472 100644 --- a/persons.csv +++ b/persons.csv @@ -9,3 +9,13 @@ dayOfBirth,firstName,lastName,monthOfBirth,yearOfBirth 18,Sofia,Marin,AUGUST,1996 25,Mihai,Dumitru,SEPTEMBER,1994 2,Laura,Bianchi,OCTOBER,1999 +12,Alex,Ivanov,JANUARY,1995 +3,Maria,Petrova,FEBRUARY,1998 +21,John,Smith,MARCH,1990 +9,Elena,Popescu,APRIL,1997 +30,Victor,Radu,MAY,1993 +14,Anna,Kowalski,JUNE,2000 +7,Daniel,Novak,JULY,1992 +18,Sofia,Marin,AUGUST,1996 +25,Mihai,Dumitru,SEPTEMBER,1994 +2,Laura,Bianchi,OCTOBER,1999 diff --git a/src/main/java/org/writer/CsvContext.java b/src/main/java/org/writer/CsvContext.java index aea0a9c..d3df7f6 100644 --- a/src/main/java/org/writer/CsvContext.java +++ b/src/main/java/org/writer/CsvContext.java @@ -11,13 +11,12 @@ @Getter @Setter public class CsvContext { - public List data; - Path path; - boolean isFileExists; - Class clazz; - Field[] fields; - String header; - BufferedWriter writer; + private List data; + private Path path; + private boolean isFileExists; + private Class clazz; + private Field[] fields; + private String header; public CsvContext(List data, String fileName) { this.data = data; diff --git a/src/main/java/org/writer/CsvFileWriter.java b/src/main/java/org/writer/CsvFileWriter.java index 84e8d67..1836324 100644 --- a/src/main/java/org/writer/CsvFileWriter.java +++ b/src/main/java/org/writer/CsvFileWriter.java @@ -20,11 +20,18 @@ *

This class is not thread-safe.

*/ public class CsvFileWriter implements Writable { - /*** - * Writes a list of objects to a CSV file + /** + * Writes a list of objects to a CSV file. + * + *

All objects in the list must be of the same type. The CSV header + * is generated automatically using reflection.

* - * @param data list of objects to be written; must not be empty - * @param fileName name of file where data will be written + * @param data list of objects to be written; must not be empty and must contain + * objects of the same type + * @param fileName name of the target CSV file + * @throws ArrayIsEmptyException if the data list is empty + * @throws IllegalArgumentException if the list contains objects of different types + * @throws IllegalStateException if an existing CSV header does not match */ @Override public void writeToFile(List data, String fileName) { @@ -34,7 +41,6 @@ public void writeToFile(List data, String fileName) { resolveMetadata(csvContext); checkFile(csvContext); - try (BufferedWriter writer = Files.newBufferedWriter( csvContext.getPath(), StandardOpenOption.CREATE, @@ -52,10 +58,11 @@ public void writeToFile(List data, String fileName) { } } - /*** - * Joins field values into a CSV string + /** + * Joins field values into a CSV string + * * @param objectToRow the object whose data we will connect - * @param fields the object whose data we will connect + * @param fields fields of the object to be serialized * @return joined row for CSV */ private String joinFieldsToCsvRow(Object objectToRow, Field[] fields) { @@ -79,7 +86,6 @@ private String joinFieldsToCsvRow(Object objectToRow, Field[] fields) { * * @param writer the {@link BufferedWriter} used to write data to the CSV file * @param csvRow the CSV-formatted row to write - * * @throws RuntimeException if an I/O error occurs while writing the row */ private void writeCsvRow(BufferedWriter writer, String csvRow) { @@ -117,15 +123,14 @@ private String escapeCsv(String value) { * CSV header matches the header generated from the current data structure.

* * @param context the CSV processing context containing file path and header - * * @throws IllegalStateException if the existing CSV header does not match - * @throws RuntimeException if an I/O error occurs while accessing the file + * @throws RuntimeException if an I/O error occurs while accessing the file */ private void checkFile(CsvContext context) { try { boolean isFileExists = Files.exists(context.getPath()) && Files.size(context.getPath()) > 0; context.setFileExists(isFileExists); - if (isFileExists){ + if (isFileExists) { validateHeader(context.getPath(), context.getHeader()); } } catch (IOException e) { @@ -137,7 +142,6 @@ private void checkFile(CsvContext context) { * Validates that the CSV context contains data to be written. * * @param context the CSV processing context - * * @throws ArrayIsEmptyException if the data list is empty */ private void validateData(CsvContext context) { @@ -149,11 +153,10 @@ private void validateData(CsvContext context) { /** * Validates that the header of an existing CSV file matches the expected header. * - * @param path the path to the existing CSV file + * @param path the path to the existing CSV file * @param dataHeader the expected CSV header generated from the data structure - * * @throws IllegalStateException if the headers do not match - * @throws RuntimeException if an I/O error occurs while reading the file + * @throws RuntimeException if an I/O error occurs while reading the file */ private void validateHeader(Path path, String dataHeader) { @@ -182,17 +185,17 @@ private void validateHeader(Path path, String dataHeader) { * @param context the CSV processing context to populate with metadata */ private void resolveMetadata(CsvContext context) { - context.clazz = context.data.get(0).getClass(); + context.setClazz(context.getData().get(0).getClass()); - Field[] fields = context.clazz.getDeclaredFields(); + Field[] fields = context.getClazz().getDeclaredFields(); Arrays.sort(fields, Comparator.comparing(Field::getName)); for (Field f : fields) { f.setAccessible(true); } - context.fields = fields; - context.header = Arrays.stream(fields) + context.setFields(fields); + context.setHeader(Arrays.stream(fields) .map(Field::getName) - .collect(Collectors.joining(",")); + .collect(Collectors.joining(","))); } } diff --git a/students.csv b/students.csv index bd5792c..15aafdf 100644 --- a/students.csv +++ b/students.csv @@ -9,3 +9,13 @@ Daniel,"[C, B, A]" Sofia,"[A, A, B]" Mihai,"[B, C, C]" Laura,"[A, B, A]" +Alex,"[A, B, A]" +Maria,"[A, A, A]" +John,"[B, C, B]" +Elena,"[A, B, C]" +Victor,"[B, B, B]" +Anna,"[A, C, B]" +Daniel,"[C, B, A]" +Sofia,"[A, A, B]" +Mihai,"[B, C, C]" +Laura,"[A, B, A]" From ff1ff7f459cbdc91a1be51ea74dcae2d78ba1460 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Thu, 15 Jan 2026 01:13:47 +0200 Subject: [PATCH 5/9] ref: some changes --- src/main/java/org/writer/{ => csv}/CsvContext.java | 0 src/main/java/org/writer/{ => csv}/CsvFileWriter.java | 0 src/main/java/org/writer/{ => csv}/Writable.java | 0 .../org/writer/{ => exception}/ArrayIsEmptyException.java | 0 src/test/java/org/writer/csv/CsvFileWriterTest.java | 4 ++++ src/test/java/org/writer/csv/testdata/StudentTestData.java | 4 ++++ 6 files changed, 8 insertions(+) rename src/main/java/org/writer/{ => csv}/CsvContext.java (100%) rename src/main/java/org/writer/{ => csv}/CsvFileWriter.java (100%) rename src/main/java/org/writer/{ => csv}/Writable.java (100%) rename src/main/java/org/writer/{ => exception}/ArrayIsEmptyException.java (100%) create mode 100644 src/test/java/org/writer/csv/CsvFileWriterTest.java create mode 100644 src/test/java/org/writer/csv/testdata/StudentTestData.java diff --git a/src/main/java/org/writer/CsvContext.java b/src/main/java/org/writer/csv/CsvContext.java similarity index 100% rename from src/main/java/org/writer/CsvContext.java rename to src/main/java/org/writer/csv/CsvContext.java diff --git a/src/main/java/org/writer/CsvFileWriter.java b/src/main/java/org/writer/csv/CsvFileWriter.java similarity index 100% rename from src/main/java/org/writer/CsvFileWriter.java rename to src/main/java/org/writer/csv/CsvFileWriter.java diff --git a/src/main/java/org/writer/Writable.java b/src/main/java/org/writer/csv/Writable.java similarity index 100% rename from src/main/java/org/writer/Writable.java rename to src/main/java/org/writer/csv/Writable.java diff --git a/src/main/java/org/writer/ArrayIsEmptyException.java b/src/main/java/org/writer/exception/ArrayIsEmptyException.java similarity index 100% rename from src/main/java/org/writer/ArrayIsEmptyException.java rename to src/main/java/org/writer/exception/ArrayIsEmptyException.java diff --git a/src/test/java/org/writer/csv/CsvFileWriterTest.java b/src/test/java/org/writer/csv/CsvFileWriterTest.java new file mode 100644 index 0000000..a4450ee --- /dev/null +++ b/src/test/java/org/writer/csv/CsvFileWriterTest.java @@ -0,0 +1,4 @@ +package org.writer; + +public class CsvFileWriterTest { +} diff --git a/src/test/java/org/writer/csv/testdata/StudentTestData.java b/src/test/java/org/writer/csv/testdata/StudentTestData.java new file mode 100644 index 0000000..82b6e40 --- /dev/null +++ b/src/test/java/org/writer/csv/testdata/StudentTestData.java @@ -0,0 +1,4 @@ +package org.writer.csv.testdata; + +public class StudentTestData { +} From e6119681870123b5a363f99c4def455d9d216f85 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Thu, 15 Jan 2026 01:13:59 +0200 Subject: [PATCH 6/9] ref: some changes --- src/main/java/org/writer/Main.java | 2 +- src/main/java/org/writer/csv/CsvContext.java | 3 +- .../java/org/writer/csv/CsvFileWriter.java | 4 +- src/main/java/org/writer/csv/Writable.java | 2 +- .../exception/ArrayIsEmptyException.java | 2 +- .../org/writer/csv/CsvFileWriterTest.java | 106 +++++++++++++++++- .../writer/csv/testdata/StudentTestData.java | 37 +++++- 7 files changed, 147 insertions(+), 9 deletions(-) diff --git a/src/main/java/org/writer/Main.java b/src/main/java/org/writer/Main.java index bc7614e..b528fb5 100644 --- a/src/main/java/org/writer/Main.java +++ b/src/main/java/org/writer/Main.java @@ -1,6 +1,6 @@ package org.writer; -import org.writer.model.Months; +import org.writer.csv.CsvFileWriter; import org.writer.model.Person; import org.writer.model.Student; diff --git a/src/main/java/org/writer/csv/CsvContext.java b/src/main/java/org/writer/csv/CsvContext.java index d3df7f6..f38a167 100644 --- a/src/main/java/org/writer/csv/CsvContext.java +++ b/src/main/java/org/writer/csv/CsvContext.java @@ -1,9 +1,8 @@ -package org.writer; +package org.writer.csv; import lombok.Getter; import lombok.Setter; -import java.io.BufferedWriter; import java.lang.reflect.Field; import java.nio.file.Path; import java.util.List; diff --git a/src/main/java/org/writer/csv/CsvFileWriter.java b/src/main/java/org/writer/csv/CsvFileWriter.java index 1836324..53f8520 100644 --- a/src/main/java/org/writer/csv/CsvFileWriter.java +++ b/src/main/java/org/writer/csv/CsvFileWriter.java @@ -1,4 +1,6 @@ -package org.writer; +package org.writer.csv; + +import org.writer.exception.ArrayIsEmptyException; import java.io.*; import java.lang.reflect.Field; diff --git a/src/main/java/org/writer/csv/Writable.java b/src/main/java/org/writer/csv/Writable.java index 03b045a..c69b0f0 100644 --- a/src/main/java/org/writer/csv/Writable.java +++ b/src/main/java/org/writer/csv/Writable.java @@ -1,4 +1,4 @@ -package org.writer; +package org.writer.csv; import java.util.List; diff --git a/src/main/java/org/writer/exception/ArrayIsEmptyException.java b/src/main/java/org/writer/exception/ArrayIsEmptyException.java index 8888eda..7c01890 100644 --- a/src/main/java/org/writer/exception/ArrayIsEmptyException.java +++ b/src/main/java/org/writer/exception/ArrayIsEmptyException.java @@ -1,4 +1,4 @@ -package org.writer; +package org.writer.exception; public class ArrayIsEmptyException extends RuntimeException { public ArrayIsEmptyException(String s) { diff --git a/src/test/java/org/writer/csv/CsvFileWriterTest.java b/src/test/java/org/writer/csv/CsvFileWriterTest.java index a4450ee..fa79388 100644 --- a/src/test/java/org/writer/csv/CsvFileWriterTest.java +++ b/src/test/java/org/writer/csv/CsvFileWriterTest.java @@ -1,4 +1,106 @@ -package org.writer; +package org.writer.csv; -public class CsvFileWriterTest { +import org.junit.jupiter.api.BeforeEach; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.api.io.TempDir; +import org.writer.csv.testdata.StudentTestData; +import org.writer.exception.ArrayIsEmptyException; +import org.writer.model.Student; + +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.util.List; + +import static org.junit.jupiter.api.Assertions.*; + +class CsvFileWriterTest { + + private final CsvFileWriter writer = new CsvFileWriter(); + + @TempDir + Path tempDir; + + private Student alex; + private Student maria; + private List data; + + @BeforeEach + void setUp() { + this.alex = StudentTestData.alex(); + this.maria = StudentTestData.maria(); + this.data = List.of(alex, maria); + } + + @Test + void shouldWriteCsvWithHeaderAndRows() throws IOException { + Path file = tempDir.resolve("students.csv"); + + writer.writeToFile(data, file.toString()); + + List lines = Files.readAllLines(file); + + assertEquals(3, lines.size()); + + // порядок полей алфавитный: name, score + assertEquals("name,score", lines.get(0)); + + assertEquals("Alex,\"[A, B, A]\"", lines.get(1)); + assertEquals("Maria,\"[A, A, A]\"", lines.get(2)); + } + + @Test + void shouldAppendDataWithoutDuplicatingHeader() throws IOException { + Path file = tempDir.resolve("students.csv"); + + writer.writeToFile(List.of(alex), file.toString()); + writer.writeToFile(List.of(maria), file.toString()); + + List lines = Files.readAllLines(file); + + assertEquals(3, lines.size()); + assertEquals("name,score", lines.get(0)); + assertEquals("Alex,\"[A, B, A]\"", lines.get(1)); + assertEquals("Maria,\"[A, A, A]\"", lines.get(2)); + } + + @Test + void shouldEscapeCsvValues() throws IOException { + Path file = tempDir.resolve("students.csv"); + + Student withComma = Student.builder() + .name("Alex, Jr.") + .score(List.of("A", "B")) + .build(); + + writer.writeToFile(List.of(withComma), file.toString()); + + List lines = Files.readAllLines(file); + + assertEquals("name,score", lines.get(0)); + assertEquals("\"Alex, Jr.\",\"[A, B]\"", lines.get(1)); + } + + @Test + void shouldThrowExceptionWhenDataIsEmpty() { + Path file = tempDir.resolve("students.csv"); + + assertThrows( + ArrayIsEmptyException.class, + () -> writer.writeToFile(List.of(), file.toString()) + ); + } + + @Test + void shouldThrowExceptionWhenHeaderDoesNotMatch() throws IOException { + Path file = tempDir.resolve("students.csv"); + + //CSV с неправильным заголовком + Files.write(file, List.of("wrong,header")); + + assertThrows( + IllegalStateException.class, + () -> writer.writeToFile(data, file.toString()) + ); + } } diff --git a/src/test/java/org/writer/csv/testdata/StudentTestData.java b/src/test/java/org/writer/csv/testdata/StudentTestData.java index 82b6e40..31ba46a 100644 --- a/src/test/java/org/writer/csv/testdata/StudentTestData.java +++ b/src/test/java/org/writer/csv/testdata/StudentTestData.java @@ -1,4 +1,39 @@ package org.writer.csv.testdata; -public class StudentTestData { +import org.writer.model.Student; + +import java.util.List; + +public final class StudentTestData { + + private StudentTestData() {} + + public static Student alex() { + return Student.builder() + .name("Alex") + .score(List.of("A", "B", "A")) + .build(); + } + + public static Student maria() { + return Student.builder() + .name("Maria") + .score(List.of("A", "A", "A")) + .build(); + } + + public static Student withCommaInName() { + return Student.builder() + .name("John, Jr.") + .score(List.of("A", "B")) + .build(); + } + + public static List students() { + return List.of( + alex(), + maria() + ); + } } + From 65a50b1cf0fc557d24c5aa46b00e4fd6f69c6461 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Thu, 15 Jan 2026 16:36:08 +0200 Subject: [PATCH 7/9] add : pipeline steps --- persons.csv | 10 - src/main/java/org/writer/Main.java | 1 + .../java/org/writer/csv/CsvFileWriter.java | 185 +++--------------- .../writer/csv/context/ContextInterface.java | 4 + .../writer/csv/{ => context}/CsvContext.java | 6 +- .../org/writer/csv/pipeline/Pipeline.java | 26 +++ .../org/writer/csv/pipeline/PipelineStep.java | 7 + .../pipeline/steps/CheckFileExistsStep.java | 19 ++ .../pipeline/steps/GenerateHeaderStep.java | 17 ++ .../pipeline/steps/ResolveMetadataStep.java | 22 +++ .../csv/pipeline/steps/ValidateDataStep.java | 14 ++ .../pipeline/steps/ValidateHeaderStep.java | 27 +++ .../steps/WriteDataToCsvFileStep.java | 92 +++++++++ .../writer/exception/CsvWriteException.java | 8 + students.csv | 10 - 15 files changed, 262 insertions(+), 186 deletions(-) create mode 100644 src/main/java/org/writer/csv/context/ContextInterface.java rename src/main/java/org/writer/csv/{ => context}/CsvContext.java (76%) create mode 100644 src/main/java/org/writer/csv/pipeline/Pipeline.java create mode 100644 src/main/java/org/writer/csv/pipeline/PipelineStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java create mode 100644 src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java create mode 100644 src/main/java/org/writer/exception/CsvWriteException.java diff --git a/persons.csv b/persons.csv index 831c472..0d71db3 100644 --- a/persons.csv +++ b/persons.csv @@ -9,13 +9,3 @@ dayOfBirth,firstName,lastName,monthOfBirth,yearOfBirth 18,Sofia,Marin,AUGUST,1996 25,Mihai,Dumitru,SEPTEMBER,1994 2,Laura,Bianchi,OCTOBER,1999 -12,Alex,Ivanov,JANUARY,1995 -3,Maria,Petrova,FEBRUARY,1998 -21,John,Smith,MARCH,1990 -9,Elena,Popescu,APRIL,1997 -30,Victor,Radu,MAY,1993 -14,Anna,Kowalski,JUNE,2000 -7,Daniel,Novak,JULY,1992 -18,Sofia,Marin,AUGUST,1996 -25,Mihai,Dumitru,SEPTEMBER,1994 -2,Laura,Bianchi,OCTOBER,1999 diff --git a/src/main/java/org/writer/Main.java b/src/main/java/org/writer/Main.java index b528fb5..02b55dd 100644 --- a/src/main/java/org/writer/Main.java +++ b/src/main/java/org/writer/Main.java @@ -14,6 +14,7 @@ public static void main(String[] args) { List personList = Person.getTestList(); List studentList = Student.getTestList(); + CsvFileWriter csvFileWriter = new CsvFileWriter(); csvFileWriter.writeToFile(personList, peopleFileName); diff --git a/src/main/java/org/writer/csv/CsvFileWriter.java b/src/main/java/org/writer/csv/CsvFileWriter.java index 53f8520..7275364 100644 --- a/src/main/java/org/writer/csv/CsvFileWriter.java +++ b/src/main/java/org/writer/csv/CsvFileWriter.java @@ -1,16 +1,11 @@ package org.writer.csv; +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.Pipeline; +import org.writer.csv.pipeline.steps.*; import org.writer.exception.ArrayIsEmptyException; -import java.io.*; -import java.lang.reflect.Field; -import java.nio.file.Files; -import java.nio.file.Path; -import java.nio.file.StandardOpenOption; -import java.util.Arrays; -import java.util.Comparator; import java.util.List; -import java.util.stream.Collectors; /** @@ -22,6 +17,10 @@ *

This class is not thread-safe.

*/ public class CsvFileWriter implements Writable { + private Pipeline writeToCsvFilePipeline; + private CsvContext csvContext; + + /** * Writes a list of objects to a CSV file. * @@ -37,167 +36,27 @@ public class CsvFileWriter implements Writable { */ @Override public void writeToFile(List data, String fileName) { - CsvContext csvContext = new CsvContext(data, fileName); - - validateData(csvContext); - resolveMetadata(csvContext); - checkFile(csvContext); - - try (BufferedWriter writer = Files.newBufferedWriter( - csvContext.getPath(), - StandardOpenOption.CREATE, - StandardOpenOption.APPEND - )) { - if (!csvContext.isFileExists()) { - writeCsvRow(writer, csvContext.getHeader()); - } - for (Object element : csvContext.getData()) { - String csvRow = joinFieldsToCsvRow(element, csvContext.getFields()); - writeCsvRow(writer, csvRow); - } - } catch (IOException e) { - throw new RuntimeException(e); - } - } - - /** - * Joins field values into a CSV string - * - * @param objectToRow the object whose data we will connect - * @param fields fields of the object to be serialized - * @return joined row for CSV - */ - private String joinFieldsToCsvRow(Object objectToRow, Field[] fields) { - return Arrays.stream(fields) - .map(field -> { - try { - Object value = field.get(objectToRow); - return escapeCsv(value == null ? "" : value.toString()); - } catch (IllegalAccessException e) { - throw new RuntimeException("Access was not permitted ", e); - } - }) - .collect(Collectors.joining(",")); - - } - - /** - * Writes a single CSV row to the given writer. - * - *

The method appends the row followed by a line separator.

- * - * @param writer the {@link BufferedWriter} used to write data to the CSV file - * @param csvRow the CSV-formatted row to write - * @throws RuntimeException if an I/O error occurs while writing the row - */ - private void writeCsvRow(BufferedWriter writer, String csvRow) { - try { - writer.write(csvRow); - writer.newLine(); - } catch (IOException e) { - throw new RuntimeException(e); - } - } - - /** - * Escapes a value according to CSV format rules. - * - *

If the value contains a comma, double quote, or line break, - * it is wrapped in double quotes and internal quotes are escaped - * by doubling them.

- * - * @param value the raw value to escape - * @return a CSV-safe representation of the value - */ - private String escapeCsv(String value) { - - if (value.contains(",") || value.contains("\"") || value.contains("\n")) { - value = value.replace("\"", "\"\""); - return "\"" + value + "\""; - } - return value; + this.csvContext = new CsvContext(data, fileName); + this.writeToCsvFilePipeline = buildPipeline(); + writeToCsvFilePipeline.execute(csvContext); } - /** - * Checks whether the target CSV file exists and validates its header if present. - * - *

If the file exists and is not empty, the method verifies that the existing - * CSV header matches the header generated from the current data structure.

- * - * @param context the CSV processing context containing file path and header - * @throws IllegalStateException if the existing CSV header does not match - * @throws RuntimeException if an I/O error occurs while accessing the file - */ - private void checkFile(CsvContext context) { - try { - boolean isFileExists = Files.exists(context.getPath()) && Files.size(context.getPath()) > 0; - context.setFileExists(isFileExists); - if (isFileExists) { - validateHeader(context.getPath(), context.getHeader()); - } - } catch (IOException e) { - throw new RuntimeException(e); - } - } - /** - * Validates that the CSV context contains data to be written. - * - * @param context the CSV processing context - * @throws ArrayIsEmptyException if the data list is empty - */ - private void validateData(CsvContext context) { - if (context.getData().isEmpty()) { - throw new ArrayIsEmptyException("Fill array with data!"); - } - } + private Pipeline buildPipeline() { + Pipeline writeToCsvFilePipeline = new Pipeline<>(); - /** - * Validates that the header of an existing CSV file matches the expected header. - * - * @param path the path to the existing CSV file - * @param dataHeader the expected CSV header generated from the data structure - * @throws IllegalStateException if the headers do not match - * @throws RuntimeException if an I/O error occurs while reading the file - */ - - private void validateHeader(Path path, String dataHeader) { - try (BufferedReader reader = Files.newBufferedReader(path)) { - String header = reader.readLine(); - boolean isHeaderEquals = header.equals(dataHeader); - - if (!isHeaderEquals) { - throw new IllegalStateException( - "CSV header mismatch. Expected: " - + header + ", actual: " + dataHeader - ); - } - } catch (IOException e) { - throw new RuntimeException(e); - } - } + writeToCsvFilePipeline.addStep(new ValidateDataStep()); + writeToCsvFilePipeline.addStep(new CheckFileExistsStep()); - /** - * Resolves reflection metadata required for CSV serialization. - * - *

The method determines the class of the data elements, extracts - * declared fields, sorts them in a deterministic order, and prepares - * them for access. It also generates a CSV header based on the field names.

- * - * @param context the CSV processing context to populate with metadata - */ - private void resolveMetadata(CsvContext context) { - context.setClazz(context.getData().get(0).getClass()); + writeToCsvFilePipeline.addStep(new ResolveMetadataStep()); - Field[] fields = context.getClazz().getDeclaredFields(); - Arrays.sort(fields, Comparator.comparing(Field::getName)); - for (Field f : fields) { - f.setAccessible(true); - } + writeToCsvFilePipeline.addStepByCondition( + this.csvContext.isFileExists(), + new ValidateDataStep(), + new GenerateHeaderStep() + ); + writeToCsvFilePipeline.addStep(new WriteDataToCsvFileStep()); - context.setFields(fields); - context.setHeader(Arrays.stream(fields) - .map(Field::getName) - .collect(Collectors.joining(","))); + return writeToCsvFilePipeline; } } diff --git a/src/main/java/org/writer/csv/context/ContextInterface.java b/src/main/java/org/writer/csv/context/ContextInterface.java new file mode 100644 index 0000000..ba274f2 --- /dev/null +++ b/src/main/java/org/writer/csv/context/ContextInterface.java @@ -0,0 +1,4 @@ +package org.writer.csv.context; + +public interface ContextInterface { +} diff --git a/src/main/java/org/writer/csv/CsvContext.java b/src/main/java/org/writer/csv/context/CsvContext.java similarity index 76% rename from src/main/java/org/writer/csv/CsvContext.java rename to src/main/java/org/writer/csv/context/CsvContext.java index f38a167..1dafd89 100644 --- a/src/main/java/org/writer/csv/CsvContext.java +++ b/src/main/java/org/writer/csv/context/CsvContext.java @@ -1,4 +1,4 @@ -package org.writer.csv; +package org.writer.csv.context; import lombok.Getter; import lombok.Setter; @@ -9,10 +9,10 @@ @Getter @Setter -public class CsvContext { +public class CsvContext implements ContextInterface { private List data; private Path path; - private boolean isFileExists; + private boolean isFileExists = false; private Class clazz; private Field[] fields; private String header; diff --git a/src/main/java/org/writer/csv/pipeline/Pipeline.java b/src/main/java/org/writer/csv/pipeline/Pipeline.java new file mode 100644 index 0000000..7f69178 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/Pipeline.java @@ -0,0 +1,26 @@ +package org.writer.csv.pipeline; + +import org.writer.csv.context.ContextInterface; + +import java.util.LinkedList; +import java.util.List; + +public class Pipeline { + private final List> steps = new LinkedList<>(); + + public void execute(TContext context) { + steps.forEach(pipelineStep -> pipelineStep.execute(context)); + } + + public void addStep(PipelineStep pipelineStep) { + steps.add(pipelineStep); + } + public void addStepByCondition(boolean condition, PipelineStep firstStep, PipelineStep secondStep){ + if (condition){ + steps.add(firstStep); + }else { + steps.add(secondStep); + } + } + +} diff --git a/src/main/java/org/writer/csv/pipeline/PipelineStep.java b/src/main/java/org/writer/csv/pipeline/PipelineStep.java new file mode 100644 index 0000000..31d0236 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/PipelineStep.java @@ -0,0 +1,7 @@ +package org.writer.csv.pipeline; + +import org.writer.csv.context.ContextInterface; + +public interface PipelineStep { + void execute(TContext context); +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java new file mode 100644 index 0000000..20e8401 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java @@ -0,0 +1,19 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; + +import java.io.IOException; +import java.nio.file.Files; + +public class CheckFileExistsStep implements PipelineStep { + @Override + public void execute(CsvContext csvcontext) { + try { + boolean isFileExists = Files.exists(csvcontext.getPath()) && Files.size(csvcontext.getPath()) > 0; + csvcontext.setFileExists(isFileExists); + } catch (IOException e) { + throw new RuntimeException(e); + } + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java new file mode 100644 index 0000000..13b96c0 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java @@ -0,0 +1,17 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; + +import java.lang.reflect.Field; +import java.util.Arrays; +import java.util.stream.Collectors; + +public class GenerateHeaderStep implements PipelineStep { + @Override + public void execute(CsvContext csvContext) { + csvContext.setHeader(Arrays.stream(csvContext.getFields()) + .map(Field::getName) + .collect(Collectors.joining(","))); + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java new file mode 100644 index 0000000..8b244dc --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java @@ -0,0 +1,22 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; + +import java.lang.reflect.Field; +import java.util.Arrays; +import java.util.Comparator; + +public class ResolveMetadataStep implements PipelineStep { + @Override + public void execute(CsvContext csvContext) { + csvContext.setClazz(csvContext.getData().get(0).getClass()); + + Field[] fields = csvContext.getClazz().getDeclaredFields(); + Arrays.sort(fields, Comparator.comparing(Field::getName)); + for (Field f : fields) { + f.setAccessible(true); + } + csvContext.setFields(fields); + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java new file mode 100644 index 0000000..000c2a4 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java @@ -0,0 +1,14 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; +import org.writer.exception.ArrayIsEmptyException; + +public class ValidateDataStep implements PipelineStep { + @Override + public void execute(CsvContext csvContext) { + if (csvContext.getData().isEmpty()) { + throw new ArrayIsEmptyException("Fill array with data!"); + } + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java b/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java new file mode 100644 index 0000000..8c02ee5 --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java @@ -0,0 +1,27 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; + +import java.io.BufferedReader; +import java.io.IOException; +import java.nio.file.Files; + +public class ValidateHeaderStep implements PipelineStep { + @Override + public void execute(CsvContext csvContext) { + try (BufferedReader reader = Files.newBufferedReader(csvContext.getPath())) { + String header = reader.readLine(); + boolean isHeaderEquals = header.equals(csvContext.getHeader()); + + if (!isHeaderEquals) { + throw new IllegalStateException( + "CSV header mismatch. Expected: " + + header + ", Generated: " + csvContext.getHeader() + ); + } + } catch (IOException e) { + throw new RuntimeException(e); + } + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java new file mode 100644 index 0000000..fcad5bf --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java @@ -0,0 +1,92 @@ +package org.writer.csv.pipeline.steps; + +import org.writer.csv.context.CsvContext; +import org.writer.csv.pipeline.PipelineStep; + +import java.io.BufferedWriter; +import java.io.IOException; +import java.lang.reflect.Field; +import java.nio.file.Files; +import java.nio.file.StandardOpenOption; +import java.util.Arrays; +import java.util.stream.Collectors; + +public class WriteDataToCsvFileStep implements PipelineStep { + @Override + public void execute(CsvContext csvContext) { + try (BufferedWriter writer = Files.newBufferedWriter( + csvContext.getPath(), + StandardOpenOption.CREATE, + StandardOpenOption.APPEND + )) { + if (!csvContext.isFileExists()) { + writeCsvRow(writer, csvContext.getHeader()); + } + for (Object element : csvContext.getData()) { + String csvRow = joinFieldsToCsvRow(element, csvContext.getFields()); + writeCsvRow(writer, csvRow); + } + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + + /** + * Joins field values into a CSV string + * + * @param objectToRow the object whose data we will connect + * @param fields fields of the object to be serialized + * @return joined row for CSV + */ + private String joinFieldsToCsvRow(Object objectToRow, Field[] fields) { + return Arrays.stream(fields) + .map(field -> { + try { + Object value = field.get(objectToRow); + return escapeCsv(value == null ? "" : value.toString()); + } catch (IllegalAccessException e) { + throw new RuntimeException("Access was not permitted ", e); + } + }) + .collect(Collectors.joining(",")); + + } + + /** + * Writes a single CSV row to the given writer. + * + *

The method appends the row followed by a line separator.

+ * + * @param writer the {@link BufferedWriter} used to write data to the CSV file + * @param csvRow the CSV-formatted row to write + * @throws RuntimeException if an I/O error occurs while writing the row + */ + private void writeCsvRow(BufferedWriter writer, String csvRow) { + try { + writer.write(csvRow); + writer.newLine(); + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + /** + * Escapes a value according to CSV format rules. + * + *

If the value contains a comma, double quote, or line break, + * it is wrapped in double quotes and internal quotes are escaped + * by doubling them.

+ * + * @param value the raw value to escape + * @return a CSV-safe representation of the value + */ + private String escapeCsv(String value) { + + if (value.contains(",") || value.contains("\"") || value.contains("\n")) { + value = value.replace("\"", "\"\""); + return "\"" + value + "\""; + } + return value; + } +} diff --git a/src/main/java/org/writer/exception/CsvWriteException.java b/src/main/java/org/writer/exception/CsvWriteException.java new file mode 100644 index 0000000..232b80c --- /dev/null +++ b/src/main/java/org/writer/exception/CsvWriteException.java @@ -0,0 +1,8 @@ +package org.writer.exception; + +import java.io.IOException; + +public class CsvWriteException extends RuntimeException { + public CsvWriteException(String failedToWriteCsvFile, IOException e) { + } +} diff --git a/students.csv b/students.csv index 15aafdf..bd5792c 100644 --- a/students.csv +++ b/students.csv @@ -9,13 +9,3 @@ Daniel,"[C, B, A]" Sofia,"[A, A, B]" Mihai,"[B, C, C]" Laura,"[A, B, A]" -Alex,"[A, B, A]" -Maria,"[A, A, A]" -John,"[B, C, B]" -Elena,"[A, B, C]" -Victor,"[B, B, B]" -Anna,"[A, C, B]" -Daniel,"[C, B, A]" -Sofia,"[A, A, B]" -Mihai,"[B, C, C]" -Laura,"[A, B, A]" From b45bbbce354429c3b00605aed18e414e3c4ccead Mon Sep 17 00:00:00 2001 From: Alexeev Date: Thu, 15 Jan 2026 17:23:16 +0200 Subject: [PATCH 8/9] fix: fix header generation --- persons.csv | 32 ++++++++++++------- src/main/java/org/writer/Main.java | 2 +- .../java/org/writer/csv/CsvFileWriter.java | 6 +--- .../org/writer/csv/context/CsvContext.java | 2 ++ .../pipeline/steps/CheckFileExistsStep.java | 2 ++ .../steps/CsvHeaderMismatchException.java | 6 ++++ .../pipeline/steps/GenerateHeaderStep.java | 24 ++++++++++++++ .../pipeline/steps/ResolveMetadataStep.java | 1 + .../csv/pipeline/steps/ValidateDataStep.java | 1 + .../pipeline/steps/ValidateHeaderStep.java | 27 ---------------- .../steps/WriteDataToCsvFileStep.java | 3 ++ .../org/writer/csv/CsvFileWriterTest.java | 3 +- students.csv | 10 ++++++ 13 files changed, 74 insertions(+), 45 deletions(-) create mode 100644 src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java delete mode 100644 src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java diff --git a/persons.csv b/persons.csv index 0d71db3..15aafdf 100644 --- a/persons.csv +++ b/persons.csv @@ -1,11 +1,21 @@ -dayOfBirth,firstName,lastName,monthOfBirth,yearOfBirth -12,Alex,Ivanov,JANUARY,1995 -3,Maria,Petrova,FEBRUARY,1998 -21,John,Smith,MARCH,1990 -9,Elena,Popescu,APRIL,1997 -30,Victor,Radu,MAY,1993 -14,Anna,Kowalski,JUNE,2000 -7,Daniel,Novak,JULY,1992 -18,Sofia,Marin,AUGUST,1996 -25,Mihai,Dumitru,SEPTEMBER,1994 -2,Laura,Bianchi,OCTOBER,1999 +name,score +Alex,"[A, B, A]" +Maria,"[A, A, A]" +John,"[B, C, B]" +Elena,"[A, B, C]" +Victor,"[B, B, B]" +Anna,"[A, C, B]" +Daniel,"[C, B, A]" +Sofia,"[A, A, B]" +Mihai,"[B, C, C]" +Laura,"[A, B, A]" +Alex,"[A, B, A]" +Maria,"[A, A, A]" +John,"[B, C, B]" +Elena,"[A, B, C]" +Victor,"[B, B, B]" +Anna,"[A, C, B]" +Daniel,"[C, B, A]" +Sofia,"[A, A, B]" +Mihai,"[B, C, C]" +Laura,"[A, B, A]" diff --git a/src/main/java/org/writer/Main.java b/src/main/java/org/writer/Main.java index 02b55dd..f9affbc 100644 --- a/src/main/java/org/writer/Main.java +++ b/src/main/java/org/writer/Main.java @@ -17,7 +17,7 @@ public static void main(String[] args) { CsvFileWriter csvFileWriter = new CsvFileWriter(); - csvFileWriter.writeToFile(personList, peopleFileName); + csvFileWriter.writeToFile(studentList, peopleFileName); csvFileWriter.writeToFile(studentList, studentshipName); diff --git a/src/main/java/org/writer/csv/CsvFileWriter.java b/src/main/java/org/writer/csv/CsvFileWriter.java index 7275364..e022e5b 100644 --- a/src/main/java/org/writer/csv/CsvFileWriter.java +++ b/src/main/java/org/writer/csv/CsvFileWriter.java @@ -50,11 +50,7 @@ private Pipeline buildPipeline() { writeToCsvFilePipeline.addStep(new ResolveMetadataStep()); - writeToCsvFilePipeline.addStepByCondition( - this.csvContext.isFileExists(), - new ValidateDataStep(), - new GenerateHeaderStep() - ); + writeToCsvFilePipeline.addStep(new GenerateHeaderStep()); writeToCsvFilePipeline.addStep(new WriteDataToCsvFileStep()); return writeToCsvFilePipeline; diff --git a/src/main/java/org/writer/csv/context/CsvContext.java b/src/main/java/org/writer/csv/context/CsvContext.java index 1dafd89..6e53aab 100644 --- a/src/main/java/org/writer/csv/context/CsvContext.java +++ b/src/main/java/org/writer/csv/context/CsvContext.java @@ -1,5 +1,6 @@ package org.writer.csv.context; +import lombok.Builder; import lombok.Getter; import lombok.Setter; @@ -9,6 +10,7 @@ @Getter @Setter +//@Builder public class CsvContext implements ContextInterface { private List data; private Path path; diff --git a/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java index 20e8401..f8104ad 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java @@ -12,6 +12,8 @@ public void execute(CsvContext csvcontext) { try { boolean isFileExists = Files.exists(csvcontext.getPath()) && Files.size(csvcontext.getPath()) > 0; csvcontext.setFileExists(isFileExists); + + System.out.println("File exists: " + isFileExists); } catch (IOException e) { throw new RuntimeException(e); } diff --git a/src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java b/src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java new file mode 100644 index 0000000..4e7714b --- /dev/null +++ b/src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java @@ -0,0 +1,6 @@ +package org.writer.csv.pipeline.steps; + +public class CsvHeaderMismatchException extends RuntimeException { + public CsvHeaderMismatchException(String s) { + } +} diff --git a/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java index 13b96c0..bc3d667 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java @@ -1,17 +1,41 @@ package org.writer.csv.pipeline.steps; +import lombok.RequiredArgsConstructor; +import lombok.extern.slf4j.Slf4j; import org.writer.csv.context.CsvContext; import org.writer.csv.pipeline.PipelineStep; +import java.io.BufferedReader; +import java.io.IOException; import java.lang.reflect.Field; +import java.nio.file.Files; import java.util.Arrays; import java.util.stream.Collectors; + public class GenerateHeaderStep implements PipelineStep { @Override public void execute(CsvContext csvContext) { csvContext.setHeader(Arrays.stream(csvContext.getFields()) .map(Field::getName) .collect(Collectors.joining(","))); + + if (csvContext.isFileExists()) { + try (BufferedReader reader = Files.newBufferedReader(csvContext.getPath())) { + String fileHeader = reader.readLine(); + + if (!fileHeader.equals(csvContext.getHeader())) { + throw new CsvHeaderMismatchException( + "CSV header mismatch. Expected: " + + csvContext.getHeader() + + ", Actual: " + + fileHeader + ); + } + } catch (IOException e) { + throw new RuntimeException(e); + } + } + } } diff --git a/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java index 8b244dc..337600d 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java @@ -18,5 +18,6 @@ public void execute(CsvContext csvContext) { f.setAccessible(true); } csvContext.setFields(fields); + System.out.println("Metadata is set..."); } } diff --git a/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java index 000c2a4..7aa5907 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java @@ -7,6 +7,7 @@ public class ValidateDataStep implements PipelineStep { @Override public void execute(CsvContext csvContext) { + System.out.println("Validate data...");; if (csvContext.getData().isEmpty()) { throw new ArrayIsEmptyException("Fill array with data!"); } diff --git a/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java b/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java deleted file mode 100644 index 8c02ee5..0000000 --- a/src/main/java/org/writer/csv/pipeline/steps/ValidateHeaderStep.java +++ /dev/null @@ -1,27 +0,0 @@ -package org.writer.csv.pipeline.steps; - -import org.writer.csv.context.CsvContext; -import org.writer.csv.pipeline.PipelineStep; - -import java.io.BufferedReader; -import java.io.IOException; -import java.nio.file.Files; - -public class ValidateHeaderStep implements PipelineStep { - @Override - public void execute(CsvContext csvContext) { - try (BufferedReader reader = Files.newBufferedReader(csvContext.getPath())) { - String header = reader.readLine(); - boolean isHeaderEquals = header.equals(csvContext.getHeader()); - - if (!isHeaderEquals) { - throw new IllegalStateException( - "CSV header mismatch. Expected: " - + header + ", Generated: " + csvContext.getHeader() - ); - } - } catch (IOException e) { - throw new RuntimeException(e); - } - } -} diff --git a/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java index fcad5bf..5efb737 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java @@ -14,6 +14,7 @@ public class WriteDataToCsvFileStep implements PipelineStep { @Override public void execute(CsvContext csvContext) { + System.out.println("Start to file writing"); try (BufferedWriter writer = Files.newBufferedWriter( csvContext.getPath(), StandardOpenOption.CREATE, @@ -26,9 +27,11 @@ public void execute(CsvContext csvContext) { String csvRow = joinFieldsToCsvRow(element, csvContext.getFields()); writeCsvRow(writer, csvRow); } + System.out.println("The data was successfully written"); } catch (IOException e) { throw new RuntimeException(e); } + } diff --git a/src/test/java/org/writer/csv/CsvFileWriterTest.java b/src/test/java/org/writer/csv/CsvFileWriterTest.java index fa79388..65c495c 100644 --- a/src/test/java/org/writer/csv/CsvFileWriterTest.java +++ b/src/test/java/org/writer/csv/CsvFileWriterTest.java @@ -3,6 +3,7 @@ import org.junit.jupiter.api.BeforeEach; import org.junit.jupiter.api.Test; import org.junit.jupiter.api.io.TempDir; +import org.writer.csv.pipeline.steps.CsvHeaderMismatchException; import org.writer.csv.testdata.StudentTestData; import org.writer.exception.ArrayIsEmptyException; import org.writer.model.Student; @@ -99,7 +100,7 @@ void shouldThrowExceptionWhenHeaderDoesNotMatch() throws IOException { Files.write(file, List.of("wrong,header")); assertThrows( - IllegalStateException.class, + CsvHeaderMismatchException.class, () -> writer.writeToFile(data, file.toString()) ); } diff --git a/students.csv b/students.csv index bd5792c..15aafdf 100644 --- a/students.csv +++ b/students.csv @@ -9,3 +9,13 @@ Daniel,"[C, B, A]" Sofia,"[A, A, B]" Mihai,"[B, C, C]" Laura,"[A, B, A]" +Alex,"[A, B, A]" +Maria,"[A, A, A]" +John,"[B, C, B]" +Elena,"[A, B, C]" +Victor,"[B, B, B]" +Anna,"[A, C, B]" +Daniel,"[C, B, A]" +Sofia,"[A, A, B]" +Mihai,"[B, C, C]" +Laura,"[A, B, A]" From 0a8c7329740c2f6a50ecd4d970d8eda5eb8a4962 Mon Sep 17 00:00:00 2001 From: Alexeev Date: Thu, 15 Jan 2026 17:32:42 +0200 Subject: [PATCH 9/9] add: javadoc --- .../csv/pipeline/steps/CheckFileExistsStep.java | 16 +++++++++++----- .../csv/pipeline/steps/GenerateHeaderStep.java | 13 +++++++++++-- .../csv/pipeline/steps/ResolveMetadataStep.java | 10 +++++++++- .../csv/pipeline/steps/ValidateDataStep.java | 7 ++++++- .../pipeline/steps/WriteDataToCsvFileStep.java | 9 +++++++++ .../CsvHeaderMismatchException.java | 2 +- .../java/org/writer/csv/CsvFileWriterTest.java | 2 +- 7 files changed, 48 insertions(+), 11 deletions(-) rename src/main/java/org/writer/{csv/pipeline/steps => exception}/CsvHeaderMismatchException.java (76%) diff --git a/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java index f8104ad..7683624 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/CheckFileExistsStep.java @@ -7,13 +7,19 @@ import java.nio.file.Files; public class CheckFileExistsStep implements PipelineStep { + /** + * Checks whether the target CSV file exists and is not empty. + * Stores the result in the CsvContext. + * + * @param csvContext context containing the path to the CSV file + * @throws RuntimeException if an I/O error occurs while checking the file + */ + @Override - public void execute(CsvContext csvcontext) { + public void execute(CsvContext csvContext) { try { - boolean isFileExists = Files.exists(csvcontext.getPath()) && Files.size(csvcontext.getPath()) > 0; - csvcontext.setFileExists(isFileExists); - - System.out.println("File exists: " + isFileExists); + boolean isFileExists = Files.exists(csvContext.getPath()) && Files.size(csvContext.getPath()) > 0; + csvContext.setFileExists(isFileExists); } catch (IOException e) { throw new RuntimeException(e); } diff --git a/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java index bc3d667..e3598f2 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/GenerateHeaderStep.java @@ -1,9 +1,8 @@ package org.writer.csv.pipeline.steps; -import lombok.RequiredArgsConstructor; -import lombok.extern.slf4j.Slf4j; import org.writer.csv.context.CsvContext; import org.writer.csv.pipeline.PipelineStep; +import org.writer.exception.CsvHeaderMismatchException; import java.io.BufferedReader; import java.io.IOException; @@ -14,8 +13,18 @@ public class GenerateHeaderStep implements PipelineStep { + /** + * Generates a CSV header based on the model fields and stores it in the context. + * If the CSV file already exists, validates that the generated header matches + * the header stored in the file. + * + * @param csvContext context containing file path and model metadata + * @throws CsvHeaderMismatchException if the existing file header does not match the generated one + * @throws RuntimeException if an I/O error occurs while reading the file + */ @Override public void execute(CsvContext csvContext) { + csvContext.setHeader(Arrays.stream(csvContext.getFields()) .map(Field::getName) .collect(Collectors.joining(","))); diff --git a/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java index 337600d..f899898 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/ResolveMetadataStep.java @@ -8,6 +8,15 @@ import java.util.Comparator; public class ResolveMetadataStep implements PipelineStep { + /** + * Resolves metadata required for CSV generation. + * Determines the model class from the data list, extracts its fields, + * sorts them by name and makes them accessible. + * + * @param csvContext context containing the data to be written + * @throws IndexOutOfBoundsException if the data list is empty + */ + @Override public void execute(CsvContext csvContext) { csvContext.setClazz(csvContext.getData().get(0).getClass()); @@ -18,6 +27,5 @@ public void execute(CsvContext csvContext) { f.setAccessible(true); } csvContext.setFields(fields); - System.out.println("Metadata is set..."); } } diff --git a/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java index 7aa5907..c342ef5 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/ValidateDataStep.java @@ -5,9 +5,14 @@ import org.writer.exception.ArrayIsEmptyException; public class ValidateDataStep implements PipelineStep { + /** + * Validates that the data list is not empty. + * + * @param csvContext context containing the data to be written + * @throws ArrayIsEmptyException if the data list is empty + */ @Override public void execute(CsvContext csvContext) { - System.out.println("Validate data...");; if (csvContext.getData().isEmpty()) { throw new ArrayIsEmptyException("Fill array with data!"); } diff --git a/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java index 5efb737..5a1b4d5 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java +++ b/src/main/java/org/writer/csv/pipeline/steps/WriteDataToCsvFileStep.java @@ -12,6 +12,15 @@ import java.util.stream.Collectors; public class WriteDataToCsvFileStep implements PipelineStep { + /** + * Writes data from the context to a CSV file. + * Writes the header if the file does not already exist, + * then appends all data rows. + * + * @param csvContext context containing file path, header and data + * @throws RuntimeException if an I/O error occurs while writing to the file + */ + @Override public void execute(CsvContext csvContext) { System.out.println("Start to file writing"); diff --git a/src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java b/src/main/java/org/writer/exception/CsvHeaderMismatchException.java similarity index 76% rename from src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java rename to src/main/java/org/writer/exception/CsvHeaderMismatchException.java index 4e7714b..47b79e6 100644 --- a/src/main/java/org/writer/csv/pipeline/steps/CsvHeaderMismatchException.java +++ b/src/main/java/org/writer/exception/CsvHeaderMismatchException.java @@ -1,4 +1,4 @@ -package org.writer.csv.pipeline.steps; +package org.writer.exception; public class CsvHeaderMismatchException extends RuntimeException { public CsvHeaderMismatchException(String s) { diff --git a/src/test/java/org/writer/csv/CsvFileWriterTest.java b/src/test/java/org/writer/csv/CsvFileWriterTest.java index 65c495c..b3dc7bf 100644 --- a/src/test/java/org/writer/csv/CsvFileWriterTest.java +++ b/src/test/java/org/writer/csv/CsvFileWriterTest.java @@ -3,7 +3,7 @@ import org.junit.jupiter.api.BeforeEach; import org.junit.jupiter.api.Test; import org.junit.jupiter.api.io.TempDir; -import org.writer.csv.pipeline.steps.CsvHeaderMismatchException; +import org.writer.exception.CsvHeaderMismatchException; import org.writer.csv.testdata.StudentTestData; import org.writer.exception.ArrayIsEmptyException; import org.writer.model.Student;