Class Trie

src/main/java/wycc/util/Trie.java:44–382

Provides a standard implementation of the Path.ID and Path.Filter interfaces. It employs the flyweight pattern to ensure every ID can only ever correspond to a single instanceof of Trie. That, it ensures that any two instances which represent the same Path.ID are, in fact, the same instan

 *
 */
public final class Trie implements Iterable<String>, Comparable<Trie> {

	// =========================================================
	// Private Constants
	// =========================================================

	private static final Trie[] ONE_CHILD = new Trie[1];

	// =========================================================
	// Public Constants
	// =========================================================

	public static final Trie ROOT = new Trie(null,"");
	public static final Trie STAR = fromString("*");
	public static final Trie STARSTAR = fromString("**");
	/**
	 * A default filter which recursively matches everything
	 */
	public static final Trie EVERYTHING = Trie.fromString("**/*");

	// =========================================================
	// Private State
	// =========================================================

	private final Trie parent;
	private final String component;
	private final int depth;
	private final boolean isConcrete;
	private Trie[] children;
	private int nchildren;

	// =========================================================
	// Public Methods
	// =========================================================


	Trie(final Trie parent, final String component) {
		this.parent = parent;
		this.component = component;
		if(parent != null) {
			this.depth = parent.depth + 1;
		} else {
			this.depth = -1;
		}
		this.children = ONE_CHILD;
		this.nchildren = 0;
		this.isConcrete = (parent == null || parent.isConcrete)
				&& !component.contains("*");
	}

	public int size() {
		return depth + 1;
	}

	public boolean isConcrete() {
		return isConcrete;
	}