/******************************************************************************* | |
* Copyright (c) 2000, 2004 IBM Corporation and others. | |
* All rights reserved. This program and the accompanying materials | |
* are made available under the terms of the Common Public License v1.0 | |
* which accompanies this distribution, and is available at | |
* http://www.eclipse.org/legal/cpl-v10.html | |
* | |
* Contributors: | |
* IBM Corporation - initial API and implementation | |
*******************************************************************************/ | |
package org.eclipse.wst.jsdt.internal.compiler.util; | |
import org.eclipse.wst.jsdt.core.compiler.CharOperation; | |
/** | |
* Hashtable of {char[] --> Object } | |
*/ | |
public final class HashtableOfObject implements Cloneable { | |
// to avoid using Enumerations, walk the individual tables skipping nulls | |
public char[] keyTable[]; | |
public Object valueTable[]; | |
public int elementSize; // number of elements in the table | |
int threshold; | |
public HashtableOfObject() { | |
this(13); | |
} | |
public HashtableOfObject(int size) { | |
this.elementSize = 0; | |
this.threshold = size; // size represents the expected number of elements | |
int extraRoom = (int) (size * 1.75f); | |
if (this.threshold == extraRoom) | |
extraRoom++; | |
this.keyTable = new char[extraRoom][]; | |
this.valueTable = new Object[extraRoom]; | |
} | |
public Object clone() throws CloneNotSupportedException { | |
HashtableOfObject result = (HashtableOfObject) super.clone(); | |
result.elementSize = this.elementSize; | |
result.threshold = this.threshold; | |
int length = this.keyTable.length; | |
result.keyTable = new char[length][]; | |
System.arraycopy(this.keyTable, 0, result.keyTable, 0, length); | |
length = this.valueTable.length; | |
result.valueTable = new Object[length]; | |
System.arraycopy(this.valueTable, 0, result.valueTable, 0, length); | |
return result; | |
} | |
public boolean containsKey(char[] key) { | |
int index = CharOperation.hashCode(key) % valueTable.length; | |
int keyLength = key.length; | |
char[] currentKey; | |
while ((currentKey = keyTable[index]) != null) { | |
if (currentKey.length == keyLength && CharOperation.equals(currentKey, key)) | |
return true; | |
index = (index + 1) % keyTable.length; | |
} | |
return false; | |
} | |
public Object get(char[] key) { | |
int index = CharOperation.hashCode(key) % valueTable.length; | |
int keyLength = key.length; | |
char[] currentKey; | |
while ((currentKey = keyTable[index]) != null) { | |
if (currentKey.length == keyLength && CharOperation.equals(currentKey, key)) | |
return valueTable[index]; | |
index = (index + 1) % keyTable.length; | |
} | |
return null; | |
} | |
public Object put(char[] key, Object value) { | |
int index = CharOperation.hashCode(key) % valueTable.length; | |
int keyLength = key.length; | |
char[] currentKey; | |
while ((currentKey = keyTable[index]) != null) { | |
if (currentKey.length == keyLength && CharOperation.equals(currentKey, key)) | |
return valueTable[index] = value; | |
index = (index + 1) % keyTable.length; | |
} | |
keyTable[index] = key; | |
valueTable[index] = value; | |
// assumes the threshold is never equal to the size of the table | |
if (++elementSize > threshold) | |
rehash(); | |
return value; | |
} | |
public Object removeKey(char[] key) { | |
int index = CharOperation.hashCode(key) % valueTable.length; | |
int keyLength = key.length; | |
char[] currentKey; | |
while ((currentKey = keyTable[index]) != null) { | |
if (currentKey.length == keyLength && CharOperation.equals(currentKey, key)) { | |
Object value = valueTable[index]; | |
elementSize--; | |
keyTable[index] = null; | |
valueTable[index] = null; | |
rehash(); | |
return value; | |
} | |
index = (index + 1) % keyTable.length; | |
} | |
return null; | |
} | |
private void rehash() { | |
HashtableOfObject newHashtable = new HashtableOfObject(elementSize * 2); // double the number of expected elements | |
char[] currentKey; | |
for (int i = keyTable.length; --i >= 0;) | |
if ((currentKey = keyTable[i]) != null) | |
newHashtable.put(currentKey, valueTable[i]); | |
this.keyTable = newHashtable.keyTable; | |
this.valueTable = newHashtable.valueTable; | |
this.threshold = newHashtable.threshold; | |
} | |
public int size() { | |
return elementSize; | |
} | |
public String toString() { | |
String s = ""; //$NON-NLS-1$ | |
Object object; | |
for (int i = 0, length = valueTable.length; i < length; i++) | |
if ((object = valueTable[i]) != null) | |
s += new String(keyTable[i]) + " -> " + object.toString() + "\n"; //$NON-NLS-2$ //$NON-NLS-1$ | |
return s; | |
} | |
} |