com.zipwhip.util.GenericLocalDirectory Maven / Gradle / Ivy

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package com.zipwhip.util;

import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

/**
 * Created by IntelliJ IDEA.
 * User: Michael
 * Date: 11/1/11
 * Time: 6:39 PM
 * 
 * Something basic/generic
 */
public class GenericLocalDirectory extends GenericDirectory implements LocalDirectory {

	protected static final Comparator COMPARATOR = new HashCodeComparator();

	protected Factory> factory = null;
	protected Map> data = null;

	public GenericLocalDirectory(Factory> factory) {
		this.factory = factory;
	}

	@Override
	public Set keySet() {
		if (data == null) {
			return Collections.emptySet();
		}

		return data.keySet();
	}

	@Override
	public boolean isEmpty() {
		if (data == null) {
			return true;
		}

		return data.isEmpty();
	}

	@Override
	public void clear() {
		if (data == null) {
			return;
		}

		data.clear();
	}

	@Override
	public Collection get(TKey key) {
		if (data == null){
			return null;
		}

		return data.get(key);
	}

	@Override
	protected void removeFromStore(TKey key) {
		if (data == null){
			return;
		}

		data.remove(key);
	}

	@Override
	protected Collection getOrCreateCollection(TKey key) {
		if (data == null) {
			synchronized (this) {
				if (data == null) {
					data = createStore();
				}
			}
		}

		Collection collection = data.get(key);

		if (collection == null) {
			synchronized (data) {
				collection = data.get(key);
				if (collection == null) {
					try {
						collection = factory.create();
					} catch (Exception e) {
						// TODO: figure out if we should add an exception to the .add() method
						throw new RuntimeException("Cannot create collection via factory", e);
					}

					data.put(key, collection);
				}
			}
		}

		return collection;
	}

	protected Map> createStore() {
		return Collections.synchronizedMap(new TreeMap>(COMPARATOR));
	}

	@Override
	protected void onDestroy() {
        if(data != null) {
		    data.clear();
        }
	}

}