MapFactory.java

package org.jcommons.common;

import java.util.*;
import java.io.Serializable;

/**
 * The MapFactory is a mechanism for specifying what kind of map is to be used
 * by some object.  For example, if you want a Counter which is backed by an
 * IdentityHashMap instead of the defaul HashMap, you can pass in an
 * IdentityHashMapFactory.
 *
 * from berkerly
 */

public abstract class MapFactory<K, V> implements Serializable {

	public static class HashMapFactory<K, V> extends MapFactory<K, V> {
		private static final long serialVersionUID = 1L;

		public Map<K, V> buildMap() {
			return new HashMap<K, V>();
		}
	}

	public static class IdentityHashMapFactory<K, V> extends MapFactory<K, V> {
		private static final long serialVersionUID = 1L;

		public Map<K, V> buildMap() {
			return new IdentityHashMap<K, V>();
		}
	}

	public static class TreeMapFactory<K, V> extends MapFactory<K, V> {
		private static final long serialVersionUID = 1L;

		public Map<K, V> buildMap() {
			return new TreeMap<K, V>();
		}
	}

	public static class WeakHashMapFactory<K, V> extends MapFactory<K, V> {
		private static final long serialVersionUID = 1L;

		public Map<K, V> buildMap() {
			return new WeakHashMap<K, V>();
		}
	}

	public abstract Map<K, V> buildMap();
}