/*******************************************************************************
* 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.che.ide.ext.java.jdt.internal.compiler.util;
import java.util.HashMap;
import java.util.Map;
/**
* A simple lookup table is a non-synchronized Hashtable, whose keys and values are Objects. It also uses linear probing to
* resolve collisions rather than a linked list of hash table entries.
*/
public final class SimpleLookupTable implements Cloneable {
// // to avoid using Enumerations, walk the individual tables skipping nulls
// public Object[] keyTable;
//
// public Object[] valueTable;
//
// public int elementSize; // number of elements in the table
//
// public int threshold;
private Map<Object, Object> map;
public SimpleLookupTable() {
this(13);
}
public SimpleLookupTable(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.keyTable = new Object[extraRoom];
// this.valueTable = new Object[extraRoom];
map = new HashMap<>(size);
}
public Object clone() {
SimpleLookupTable result = new SimpleLookupTable();
// result.elementSize = this.elementSize;
// result.threshold = this.threshold;
//
// int length = this.keyTable.length;
// result.keyTable = new Object[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);
result.map = new HashMap<>(map);
return result;
}
public Object[] keys() {
return map.keySet().toArray();
}
public boolean containsKey(Object key) {
// int length = this.keyTable.length;
// int index = (key.hashCode() & 0x7FFFFFFF) % length;
// Object currentKey;
// while ((currentKey = this.keyTable[index]) != null) {
// if (currentKey.equals(key))
// return true;
// if (++index == length)
// index = 0;
// }
// return false;
return map.containsKey(key);
}
public Object[] getArrayValues() {
return map.values().toArray();
}
public Object get(Object key) {
// int length = this.keyTable.length;
// int index = (key.hashCode() & 0x7FFFFFFF) % length;
// Object currentKey;
// while ((currentKey = this.keyTable[index]) != null) {
// if (currentKey.equals(key))
// return this.valueTable[index];
// if (++index == length)
// index = 0;
// }
// return null;
return map.get(key);
}
public Object getKey(Object key) {
// int length = this.keyTable.length;
// int index = (key.hashCode() & 0x7FFFFFFF) % length;
// Object currentKey;
// while ((currentKey = this.keyTable[index]) != null) {
// if (currentKey.equals(key))
// return currentKey;
// if (++index == length)
// index = 0;
// }
// return key;
if (map.containsKey(key)) {
return key;
}
return null;
}
public Object keyForValue(Object valueToMatch) {
// if (valueToMatch != null)
// for (int i = 0, l = this.keyTable.length; i < l; i++)
// if (this.keyTable[i] != null && valueToMatch.equals(this.valueTable[i]))
// return this.keyTable[i];
// return null;
for (Map.Entry<Object, Object> entry : map.entrySet()) {
if (entry.getValue().equals(valueToMatch)) {
return entry.getKey();
}
}
return null;
}
public Object put(Object key, Object value) {
// int length = this.keyTable.length;
// int index = (key.hashCode() & 0x7FFFFFFF) % length;
// Object currentKey;
// while ((currentKey = this.keyTable[index]) != null) {
// if (currentKey.equals(key))
// return this.valueTable[index] = value;
// if (++index == length)
// index = 0;
// }
// this.keyTable[index] = key;
// this.valueTable[index] = value;
//
// // assumes the threshold is never equal to the size of the table
// if (++this.elementSize > this.threshold)
// rehash();
// return value;
return map.put(key, value);
}
public Object removeKey(Object key) {
// int length = this.keyTable.length;
// int index = (key.hashCode() & 0x7FFFFFFF) % length;
// Object currentKey;
// while ((currentKey = this.keyTable[index]) != null) {
// if (currentKey.equals(key)) {
// this.elementSize--;
// Object oldValue = this.valueTable[index];
// this.keyTable[index] = null;
// this.valueTable[index] = null;
// if (this.keyTable[index + 1 == length ? 0 : index + 1] != null)
// rehash(); // only needed if a possible collision existed
// return oldValue;
// }
// if (++index == length)
// index = 0;
// }
// return null;
return map.remove(key);
}
public void removeValue(Object valueToRemove) {
// boolean rehash = false;
// for (int i = 0, l = this.valueTable.length; i < l; i++) {
// Object value = this.valueTable[i];
// if (value != null && value.equals(valueToRemove)) {
// this.elementSize--;
// this.keyTable[i] = null;
// this.valueTable[i] = null;
// if (!rehash && this.keyTable[i + 1 == l ? 0 : i + 1] != null)
// rehash = true; // only needed if a possible collision existed
// }
// }
// if (rehash)
// rehash();
Object key = keyForValue(valueToRemove);
if (key != null) {
map.remove(key);
}
}
// private void rehash() {
// SimpleLookupTable newLookupTable = new SimpleLookupTable(this.elementSize * 2); // double the number of expected elements
// Object currentKey;
// for (int i = this.keyTable.length; --i >= 0; )
// if ((currentKey = this.keyTable[i]) != null)
// newLookupTable.put(currentKey, this.valueTable[i]);
//
// this.keyTable = newLookupTable.keyTable;
// this.valueTable = newLookupTable.valueTable;
// this.elementSize = newLookupTable.elementSize;
// this.threshold = newLookupTable.threshold;
// }
public String toString() {
// String s = ""; //$NON-NLS-1$
// Object object;
// for (int i = 0, l = this.valueTable.length; i < l; i++)
// if ((object = this.valueTable[i]) != null)
// s += this.keyTable[i].toString() + " -> " + object.toString() + "\n"; //$NON-NLS-2$ //$NON-NLS-1$
// return s;
return map.toString();
}
}