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Work immutably, robustly and in a knowledge-oriented way with Entity maps in Java.

There is a newer version: 0.3.13

package org.pcollections;

import java.util.Map;
import java.util.Map.Entry;




/**
 *
 * A static convenience class for creating efficient persistent maps.
 * 
 * This class simply creates HashPMaps backed by IntTreePMaps.
 * 
 * @author harold
 */
public final class HashTreePMap {
	// not instantiable (or subclassable):
	private HashTreePMap() {}
	
	private static final HashPMap EMPTY
		= HashPMap.empty(IntTreePMap.>>empty());

	/**
	 * @param 
	 * @param 
	 * @return an empty map
	 */
	@SuppressWarnings("unchecked")
	public static  HashPMap empty() {
		return (HashPMap)EMPTY; }
	
	/**
	 * @param 
	 * @param 
	 * @param key
	 * @param value
	 * @return empty().plus(key, value)
	 */
	public static  HashPMap singleton(final K key, final V value) {
		return HashTreePMap.empty().plus(key, value); }
	
	/**
	 * @param 
	 * @param 
	 * @param map
	 * @return empty().plusAll(map)
	 */
	public static  HashPMap from(final Map map) {
		return HashTreePMap.empty().plusAll(map); }
}