Add version check

Add CheckResult

Author: Lezurex

src/main/java/com/lezurex/githubversionchecker/CheckResult.java

@@ -0,0 +1,17 @@
+package com.lezurex.githubversionchecker;
+
+import lombok.Getter;
+
+@Getter
+public class CheckResult {
+
+    private ReleaseVersion version;
+    private String pageLink;
+    private VersionState versionState;
+
+    public CheckResult(ReleaseVersion version, String pageLink, VersionState versionState) {
+        this.version = version;
+        this.pageLink = pageLink;
+        this.versionState = versionState;
+    }
+}

src/main/java/com/lezurex/githubversionchecker/GithubVersionChecker.java

@@ -1,12 +1,19 @@
 package com.lezurex.githubversionchecker;
 
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.lezurex.githubversionchecker.exceptions.NoReleaseFoundException;
 import com.lezurex.githubversionchecker.exceptions.RepoNotFoundException;
 
 import javax.net.ssl.HttpsURLConnection;
+import java.io.BufferedReader;
 import java.io.IOException;
-import java.net.HttpURLConnection;
+import java.io.InputStreamReader;
 import java.net.URL;
 
+import static java.net.HttpURLConnection.HTTP_OK;
+
 public class GithubVersionChecker {
 
     /**
@@ -18,26 +25,79 @@ public class GithubVersionChecker {
      */
     private final String repo;
     private final ReleaseVersion currentVersion;
+    private final boolean includePreReleases;
 
     /**
      * @param username Username where the targeted repo is located
      * @param repo Name of the repository on GitHub
      * @param currentVersion The current version running
+     * @param includePreReleases Whether pre releases should be tested (default: false)
      */
-    public GithubVersionChecker(String username, String repo, ReleaseVersion currentVersion) {
+    public GithubVersionChecker(String username, String repo, ReleaseVersion currentVersion, boolean includePreReleases) {
         this.username = username;
         this.repo = repo;
         this.currentVersion = currentVersion;
+        this.includePreReleases = includePreReleases;
 
         try {
             URL url = new URL(String.format("https://api.github.com/repos/%s/%s", this.username, this.repo));
             HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
             con.setRequestMethod("GET");
-            if (con.getResponseCode() != HttpURLConnection.HTTP_OK) {
+            if (con.getResponseCode() != HTTP_OK) {
                 throw new RepoNotFoundException(this.username, this.repo);
             }
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
+
+    /**
+     * @param username Username where the targeted repo is located
+     * @param repo Name of the repository on GitHub
+     * @param currentVersion The current version running
+     */
+    public GithubVersionChecker(String username, String repo, ReleaseVersion currentVersion) {
+        this(username, repo, currentVersion, false);
+    }
+
+    public CheckResult check() {
+        String queryURL = "https://api.github.com/repos/%s/%s/releases/latest";
+        if (this.includePreReleases)
+            queryURL = "https://api.github.com/repos/%s/%s/releases?per_page=1";
+        try {
+            URL url = new URL(String.format(queryURL, this.username, this.repo));
+            HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
+            con.setRequestMethod("GET");
+            if (con.getResponseCode() != HTTP_OK) throw new NoReleaseFoundException(this.username, this.repo);
+
+            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+
+            JsonObject releaseData;
+            if (this.includePreReleases) {
+                JsonArray jsonArray = JsonParser.parseReader(in).getAsJsonArray();
+                if (jsonArray.size() == 0) throw new NoReleaseFoundException(this.username, this.repo);
+                releaseData = jsonArray.get(0).getAsJsonObject();
+            } else
+                releaseData = JsonParser.parseReader(in).getAsJsonObject();
+            in.close();
+            con.disconnect();
+
+            ReleaseVersion githubVersion = new ReleaseVersion(releaseData.get("tag_name").getAsString());
+            String pageLink = releaseData.get("html_url").getAsString();
+            switch (this.currentVersion.compareTo(githubVersion)) {
+                case -1:
+                    return new CheckResult(githubVersion, pageLink, VersionState.OUTDATED);
+                case 0:
+                    return new CheckResult(githubVersion, pageLink, VersionState.UP_TO_DATE);
+                case 1:
+                    return new CheckResult(githubVersion, pageLink, VersionState.NEWER);
+                default:
+                    return null;
+            }
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
 }

src/main/java/com/lezurex/githubversionchecker/exceptions/NoReleaseFoundException.java

@@ -0,0 +1,20 @@
+package com.lezurex.githubversionchecker.exceptions;
+
+import lombok.Getter;
+
+@Getter
+public class NoReleaseFoundException extends RuntimeException {
+
+    private final String username;
+    private final String repo;
+
+    public NoReleaseFoundException(String username, String repo) {
+        this.username = username;
+        this.repo = repo;
+    }
+
+    @Override
+    public String getMessage() {
+        return String.format("Couldn't find an existing release in repo \"%s/%s\"! If you are the maintainer of this application, please create a release!", username, repo);
+    }
+}

src/main/java/com/lezurex/githubversionchecker/exceptions/RepoNotFoundException.java

@@ -15,6 +15,6 @@ public RepoNotFoundException(String username, String repo) {
 
     @Override
     public String getMessage() {
-        return String.format("Repo %s/%s couldn't be found on GitHub! Does it exist and", username, repo);
+        return String.format("Repo \"%s/%s\" couldn't be found on GitHub! Does it exist and is it public?", username, repo);
     }
 }