ModifierSet.java

package org.z3950.zing.cql;

import java.util.ArrayList;
import java.util.List;

/**
 * Represents a base String and a set of Modifiers.
 * <P>
 * This class is used as a workhorse delegate by both CQLRelation and
 * CQLProxNode - two functionally very separate classes that happen to
 * require similar data structures and functionality.
 * </P>
 * <P>
 * A ModifierSet consists of a ``base'' string together with a set of
 * zero or more <I>type</I> <I>comparison</I> <I>value</I> pairs,
 * where type, comparison and value are all strings.
 * </P>
 *
 */
public class ModifierSet {
    private String base;
    private List<Modifier> modifiers;

    /**
     * Creates a new ModifierSet with the specified base.
     */
    public ModifierSet(String base) {
	this.base = base;
	modifiers = new ArrayList<Modifier>();
    }

    /**
     * Returns the base string with which the ModifierSet was created.
     */
    public String getBase() {
	return base;
    }

    /**
     * Adds a modifier of the specified <code>type</code>,
     * <code>comparison</code> and <code>value</code> to a ModifierSet.
     */
    public Modifier addModifier(String type, String comparison, String value) {
	Modifier modifier = new Modifier(type, comparison, value);
	modifiers.add(modifier);
	return modifier;
    }

    /**
     * Adds a modifier of the specified <code>type</code>, but with no
     * <code>comparison</code> and <code>value</code>, to a ModifierSet.
     */
    public Modifier addModifier(String type) {
	Modifier modifier = new Modifier(type);
	modifiers.add(modifier);
	return modifier;
    }

    /**
     * Returns the value of the modifier in the specified ModifierSet
     * that corresponds to the specified type.
     */
    public String modifier(String type) {
	int n = modifiers.size();
	for (int i = 0; i < n; i++) {
	    Modifier mod = modifiers.get(i);
	    if (mod.type.equals(type))
		return mod.value;
	}
	return null;
    }

    /**
     * Returns an array of the modifiers in a ModifierSet.
     * @return
     *	An array of Modifiers.
     */
    public List<Modifier> getModifiers() {
	return modifiers;
    }

    void toXCQLInternal(XCQLBuilder b, int level,
        String topLevelElement, String valueElement) {
	b.indent(level).append("<").append(topLevelElement).
            append(">\n").indent(level + 1).append("<").
            append(valueElement).append(">").xq(base).append("</").
            append(valueElement).append(">\n");
	if (modifiers.size() > 0) {
	    b.indent(level + 1).append("<modifiers>\n");
	    for (int i = 0; i < modifiers.size(); i++) {
              modifiers.get(i).toXCQLInternal(b, level+2, "comparison");
	    }
	    b.indent(level + 1).append("</modifiers>\n");
	}
	b.indent(level).append("</").append(topLevelElement).append(">\n");
    }

    public String toCQL() {
	StringBuilder buf = new StringBuilder(base);
	for (int i = 0; i < modifiers.size(); i++) {
	    buf.append("/").append(modifiers.get(i).toCQL());
	}

	return buf.toString();
    }

    public static void main(String[] args) {
	if (args.length < 1) {
	    System.err.println("Usage: ModifierSet <base> [<type> <comparison> <name>]...");
	    System.exit(1);
	}

	ModifierSet res = new ModifierSet(args[0]);
	for (int i = 1; i < args.length; i += 3) {
	    res.addModifier(args[i], args[i+1], args[i+2]);
	}

	System.out.println(res.toCQL());
    }
}