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	/*
	* Copyright (c) 2004, 2012, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.util;

	import java.util.Iterator;
	import java.util.Map;
	import java.util.Set;
	import java.util.AbstractMap;
	import java.util.AbstractSet;
	import java.util.NoSuchElementException;


	/**
	* A precomputed hash map.
	*
	* <p> Subclasses of this class are of the following form:
	*
	* <blockquote><pre>
	* class FooMap
	* extends sun.util.PreHashedMap<String>
	* {
	*
	* private FooMap() {
	* super(ROWS, SIZE, SHIFT, MASK);
	* }
	*
	* protected void init(Object[] ht) {
	* ht[0] = new Object[] { "key-1", value_1 };
	* ht[1] = new Object[] { "key-2", value_2,
	* new Object { "key-3", value_3 } };
	* ...
	* }
	*
	* }</pre></blockquote>
	*
	* <p> The {@code init} method is invoked by the {@code PreHashedMap}
	* constructor with an object array long enough for the map's rows. The method
	* must construct the hash chain for each row and store it in the appropriate
	* element of the array.
	*
	* <p> Each entry in the map is represented by a unique hash-chain node. The
	* final node of a hash chain is a two-element object array whose first element
	* is the entry's key and whose second element is the entry's value. A
	* non-final node of a hash chain is a three-element object array whose first
	* two elements are the entry's key and value and whose third element is the
	* next node in the chain.
	*
	* <p> Instances of this class are mutable and are not safe for concurrent
	* access. They may be made immutable and thread-safe via the appropriate
	* methods in the {@link java.util.Collections} utility class.
	*
	* <p> In the JDK build, subclasses of this class are typically created via the
	* {@code Hasher} program in the {@code make/tools/Hasher} directory.
	*
	* @author Mark Reinhold
	* @since 1.5
	*
	* @see java.util.AbstractMap
	*/

	public abstract class PreHashedMap<V>
	extends AbstractMap<String,V>
	{

	private final int rows;
	private final int size;
	private final int shift;
	private final int mask;
	private final Object[] ht;

	/**
	* Creates a new map.
	*
	* <p> This constructor invokes the {@link #init init} method, passing it a
	* newly-constructed row array that is {@code rows} elements long.
	*
	* @param rows
	* The number of rows in the map
	* @param size
	* The number of entries in the map
	* @param shift
	* The value by which hash codes are right-shifted
	* @param mask
	* The value with which hash codes are masked after being shifted
	*/
	protected PreHashedMap(int rows, int size, int shift, int mask) {
	this.rows = rows;
	this.size = size;
	this.shift = shift;
	this.mask = mask;
	this.ht = new Object[rows];
	init(ht);
	}

	/**
	* Initializes this map.
	*
	* <p> This method must construct the map's hash chains and store them into
	* the appropriate elements of the given hash-table row array.
	*
	* @param ht The row array to be initialized
	*/
	protected abstract void init(Object[] ht);

	@SuppressWarnings("unchecked")
	private V toV(Object x) {
	return (V)x;
	}

	public V get(Object k) {
	int h = (k.hashCode() >> shift) & mask;
	Object[] a = (Object[])ht[h];
	if (a == null) return null;
	for (;;) {
	if (a[0].equals(k))
	return toV(a[1]);
	if (a.length < 3)
	return null;
	a = (Object[])a[2];
	}
	}

	/**
	* @throws UnsupportedOperationException
	* If the given key is not part of this map's initial key set
	*/
	public V put(String k, V v) {
	int h = (k.hashCode() >> shift) & mask;
	Object[] a = (Object[])ht[h];
	if (a == null)
	throw new UnsupportedOperationException(k);
	for (;;) {
	if (a[0].equals(k)) {
	V ov = toV(a[1]);
	a[1] = v;
	return ov;
	}
	if (a.length < 3)
	throw new UnsupportedOperationException(k);
	a = (Object[])a[2];
	}
	}

	public Set<String> keySet() {
	return new AbstractSet<> () {

	public int size() {
	return size;
	}

	public Iterator<String> iterator() {
	return new Iterator<>() {
	private int i = -1;
	Object[] a = null;
	String cur = null;

	private boolean findNext() {
	if (a != null) {
	if (a.length == 3) {
	a = (Object[])a[2];
	cur = (String)a[0];
	return true;
	}
	i++;
	a = null;
	}
	cur = null;
	if (i >= rows)
	return false;
	if (i < 0 \|\| ht[i] == null) {
	do {
	if (++i >= rows)
	return false;
	} while (ht[i] == null);
	}
	a = (Object[])ht[i];
	cur = (String)a[0];
	return true;
	}

	public boolean hasNext() {
	if (cur != null)
	return true;
	return findNext();
	}

	public String next() {
	if (cur == null) {
	if (!findNext())
	throw new NoSuchElementException();
	}
	String s = cur;
	cur = null;
	return s;
	}

	public void remove() {
	throw new UnsupportedOperationException();
	}

	};
	}
	};
	}

	public Set<Map.Entry<String,V>> entrySet() {
	return new AbstractSet<Map.Entry<String,V>> () {

	public int size() {
	return size;
	}

	public Iterator<Map.Entry<String,V>> iterator() {
	return new Iterator<Map.Entry<String,V>>() {
	final Iterator<String> i = keySet().iterator();

	public boolean hasNext() {
	return i.hasNext();
	}

	public Map.Entry<String,V> next() {
	return new Map.Entry<String,V>() {
	String k = i.next();
	public String getKey() { return k; }
	public V getValue() { return get(k); }
	public int hashCode() {
	V v = get(k);
	return (k.hashCode()
	+ (v == null
	? 0
	: v.hashCode()));
	}
	public boolean equals(Object ob) {
	if (ob == this)
	return true;
	if (!(ob instanceof Map.Entry))
	return false;
	Map.Entry<?,?> that = (Map.Entry<?,?>)ob;
	return ((this.getKey() == null
	? that.getKey() == null
	: this.getKey()
	.equals(that.getKey()))
	&&
	(this.getValue() == null
	? that.getValue() == null
	: this.getValue()
	.equals(that.getValue())));
	}
	public V setValue(V v) {
	throw new UnsupportedOperationException();
	}
	};
	}

	public void remove() {
	throw new UnsupportedOperationException();
	}

	};
	}
	};
	}

	}

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