- /*
- * The Apache Software License, Version 1.1
- *
- *
- * Copyright (c) 2001, 2002 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution,
- * if any, must include the following acknowledgment:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgment may appear in the software itself,
- * if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Xerces" and "Apache Software Foundation" must
- * not be used to endorse or promote products derived from this
- * software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache",
- * nor may "Apache" appear in their name, without prior written
- * permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation and was
- * originally based on software copyright (c) 2001, International
- * Business Machines, Inc., http://www.apache.org. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
-
- package com.sun.org.apache.xerces.internal.util;
-
-
- /**
- * This class is an unsynchronized hash table primary used for String
- * to Object mapping.
- * <p>
- * The hash code uses the same algorithm as SymbolTable class.
- *
- * @author Elena Litani
- * @version $Id: SymbolHash.java,v 1.7 2003/05/08 20:12:00 elena Exp $
- */
- public class SymbolHash {
-
- //
- // Constants
- //
-
- /** Default table size. */
- protected int fTableSize = 101;
-
- //
- // Data
- //
-
- /** Buckets. */
- protected Entry[] fBuckets;
-
- /** Number of elements. */
- protected int fNum = 0;
-
- //
- // Constructors
- //
-
- /** Constructs a key table with the default size. */
- public SymbolHash() {
- fBuckets = new Entry[fTableSize];
- }
-
- /**
- * Constructs a key table with a given size.
- *
- * @param size the size of the key table.
- */
- public SymbolHash(int size) {
- fTableSize = size;
- fBuckets = new Entry[fTableSize];
- }
-
- //
- // Public methods
- //
-
- /**
- * Adds the key/value mapping to the key table. If the key already exists,
- * the previous value associated with this key is overwritten by the new
- * value.
- *
- * @param key
- * @param value
- */
- public void put(Object key, Object value) {
- int bucket = (key.hashCode() & 0x7FFFFFFF) % fTableSize;
- Entry entry = search(key, bucket);
-
- // replace old value
- if (entry != null) {
- entry.value = value;
- }
- // create new entry
- else {
- entry = new Entry(key, value, fBuckets[bucket]);
- fBuckets[bucket] = entry;
- fNum++;
- }
- }
-
- /**
- * Get the value associated with the given key.
- *
- * @param key
- * @return the value associated with the given key.
- */
- public Object get(Object key) {
- int bucket = (key.hashCode() & 0x7FFFFFFF) % fTableSize;
- Entry entry = search(key, bucket);
- if (entry != null) {
- return entry.value;
- }
- return null;
- }
-
- /**
- * Get the number of key/value pairs stored in this table.
- *
- * @return the number of key/value pairs stored in this table.
- */
- public int getLength() {
- return fNum;
- }
-
- /**
- * Add all values to the given array. The array must have enough entry.
- *
- * @param elements the array to store the elements
- * @param from where to start store element in the array
- * @return number of elements copied to the array
- */
- public int getValues(Object[] elements, int from) {
- for (int i=0, j=0; i<fTableSize && j<fNum; i++) {
- for (Entry entry = fBuckets[i]; entry != null; entry = entry.next) {
- elements[from+j] = entry.value;
- j++;
- }
- }
- return fNum;
- }
-
- /**
- * Make a clone of this object.
- */
- public SymbolHash makeClone() {
- SymbolHash newTable = new SymbolHash(fTableSize);
- newTable.fNum = fNum;
- for (int i = 0; i < fTableSize; i++) {
- if (fBuckets[i] != null)
- newTable.fBuckets[i] = fBuckets[i].makeClone();
- }
- return newTable;
- }
-
- /**
- * Remove all key/value assocaition. This tries to save a bit of GC'ing
- * by at least keeping the fBuckets array around.
- */
- public void clear() {
- for (int i=0; i<fTableSize; i++) {
- fBuckets[i] = null;
- }
- fNum = 0;
- } // clear(): void
-
- protected Entry search(Object key, int bucket) {
- // search for identical key
- for (Entry entry = fBuckets[bucket]; entry != null; entry = entry.next) {
- if (key.equals(entry.key))
- return entry;
- }
- return null;
- }
-
- //
- // Classes
- //
-
- /**
- * This class is a key table entry. Each entry acts as a node
- * in a linked list.
- */
- protected static final class Entry {
- // key/value
- public Object key;
- public Object value;
- /** The next entry. */
- public Entry next;
-
- public Entry() {
- key = null;
- value = null;
- next = null;
- }
-
- public Entry(Object key, Object value, Entry next) {
- this.key = key;
- this.value = value;
- this.next = next;
- }
-
- public Entry makeClone() {
- Entry entry = new Entry();
- entry.key = key;
- entry.value = value;
- if (next != null)
- entry.next = next.makeClone();
- return entry;
- }
- } // entry
-
- } // class SymbolHash
-