search/org/eclipse/jdt/internal/core/index/impl/HashtableOfObject.java

package org.eclipse.jdt.internal.core.index.impl;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import org.eclipse.jdt.internal.compiler.util.*;

public final class HashtableOfObject {
	// 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 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.prefixEquals(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.prefixEquals(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.prefixEquals(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;
	}
	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= ""/*nonNLS*/;
		Object object;
		for (int i= 0, length= valueTable.length; i < length; i++)
			if ((object= valueTable[i]) != null)
				s += new String(keyTable[i]) + " -> "/*nonNLS*/ + object.toString() + "\n"/*nonNLS*/;
		return s;
	}
}