/*******************************************************************************
* Copyright (c) 2000, 2009 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.core.builder;
public class StringSet {
// to avoid using Enumerations, walk the individual values skipping nulls
public String[] values;
public int elementSize; // number of elements in the table
public int threshold;
public StringSet(int size) {
this.elementSize= 0;
this.threshold= size; // size represents the expected number of elements
int extraRoom= (int)(size * 1.5f);
if (this.threshold == extraRoom)
extraRoom++;
this.values= new String[extraRoom];
}
public boolean add(String value) {
int length= this.values.length;
int index= (value.hashCode() & 0x7FFFFFFF) % length;
String current;
while ((current= this.values[index]) != null) {
if (value.equals(current))
return false; // did not add it since it already existed
if (++index == length)
index= 0;
}
this.values[index]= value;
// assumes the threshold is never equal to the size of the table
if (++this.elementSize > this.threshold)
rehash();
return true;
}
public void clear() {
for (int i= this.values.length; --i >= 0;)
this.values[i]= null;
this.elementSize= 0;
}
public boolean includes(String value) {
int length= this.values.length;
int index= (value.hashCode() & 0x7FFFFFFF) % length;
String current;
while ((current= this.values[index]) != null) {
if (value.equals(current))
return true;
if (++index == length)
index= 0;
}
return false;
}
private void rehash() {
StringSet newSet= new StringSet(this.elementSize * 2); // double the number of expected elements
String current;
for (int i= this.values.length; --i >= 0;)
if ((current= this.values[i]) != null)
newSet.add(current);
this.values= newSet.values;
this.elementSize= newSet.elementSize;
this.threshold= newSet.threshold;
}
public String toString() {
String s= ""; //$NON-NLS-1$
String value;
for (int i= 0, l= this.values.length; i < l; i++)
if ((value= this.values[i]) != null)
s+= value + "\n"; //$NON-NLS-1$
return s;
}
}