SimpleSet.java

/*******************************************************************************
 * 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.HashSet;
import java.util.Set;

/**
 * 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 SimpleSet implements Cloneable {

//    // to avoid using Enumerations, walk the individual values skipping nulls
//    public Object[] values;
//
//    public int elementSize; // number of elements in the table
//
//    public int threshold;

    private Set<Object> values;

    public SimpleSet() {
        this(13);
    }

    public SimpleSet(int size) {
        if (size < 3)
            size = 3;
//        this.elementSize = 0;
//        this.threshold = size + 1; // size is the expected number of elements
        this.values = new HashSet<>(2 * size + 1);

    }

    public Object add(Object object) {
//        int length = this.values.length;
//        int index = (object.hashCode() & 0x7FFFFFFF) % length;
//        Object current;
//        while ((current = this.values[index]) != null) {
//            if (current.equals(object))
//                return this.values[index] = object;
//            if (++index == length)
//                index = 0;
//        }
//        this.values[index] = object;
//
//        // assumes the threshold is never equal to the size of the table
//        if (++this.elementSize > this.threshold)
//            rehash();
        values.add(object);
        return object;
    }

//    public Object addIfNotIncluded(Object object) {
//        int length = this.values.length;
//        int index = (object.hashCode() & 0x7FFFFFFF) % length;
//        Object current;
//        while ((current = this.values[index]) != null) {
//            if (current.equals(object))
//                return null; // already existed
//            if (++index == length)
//                index = 0;
//        }
//        this.values[index] = object;
//
//        // assumes the threshold is never equal to the size of the table
//        if (++this.elementSize > this.threshold)
//            rehash();
//        values.contains(object)
//        return object;
//    }

    public int size() {
        return values.size();
    }

    public void asArray(Object[] copy) {
        if (values.size() != copy.length)
            throw new IllegalArgumentException();
        int index = values.size();
        for (Object obj : values)
            if (obj != null)
                copy[--index] = obj;
    }

    public Object[] getArrayValues() {
        return values.toArray();
    }

    public void clear() {
//        for (int i = this.values.length; --i >= 0; )
//            this.values[i] = null;
//        this.elementSize = 0;
        values.clear();
    }

    public Object clone() {
        SimpleSet result = new SimpleSet();
//        result.elementSize = this.elementSize;
//        result.threshold = this.threshold;
//
//        int length = this.values.length;
//        result.values = new Object[length];
//        System.arraycopy(this.values, 0, result.values, 0, length);
        result.values = new HashSet<>(values);
        return result;
    }

    public boolean includes(Object object) {
//        int length = this.values.length;
//        int index = (object.hashCode() & 0x7FFFFFFF) % length;
//        Object current;
//        while ((current = this.values[index]) != null) {
//            if (current.equals(object))
//                return true;
//            if (++index == length)
//                index = 0;
//        }
//        return false;
        return values.contains(object);
    }

    public Object remove(Object object) {
//        int length = this.values.length;
//        int index = (object.hashCode() & 0x7FFFFFFF) % length;
//        Object current;
//        while ((current = this.values[index]) != null) {
//            if (current.equals(object)) {
//                this.elementSize--;
//                Object oldValue = this.values[index];
//                this.values[index] = null;
//                if (this.values[index + 1 == length ? 0 : index + 1] != null)
//                    rehash(); // only needed if a possible collision existed
//                return oldValue;
//            }
//            if (++index == length)
//                index = 0;
//        }
//        return null;
        if (values.remove(object)) {
            return object;
        }
        return null;
    }

//    private void rehash() {
//        SimpleSet newSet = new SimpleSet(this.elementSize * 2); // double the number of expected elements
//        Object 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 = ""; //$NON-NLS-1$
//        Object object;
//        for (int i = 0, l = this.values.length; i < l; i++)
//            if ((object = this.values[i]) != null)
//                s += object.toString() + "\n"; //$NON-NLS-1$
//        return s;
        return values.toString();
    }
}