com.nextep.designer.util.IdentitySet.java Source code

Introduction

Here is the source code for com.nextep.designer.util.IdentitySet.java

Source

/*******************************************************************************
 * Copyright (c) 2011 neXtep Software and contributors.
 * All rights reserved.
 *
 * This file is part of neXtep designer.
 *
 * NeXtep designer is free software: you can redistribute it 
 * and/or modify it under the terms of the GNU General Public 
 * License as published by the Free Software Foundation, either 
 * version 3 of the License, or any later version.
 *
 * NeXtep designer is distributed in the hope that it will be 
 * useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Foobar.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Contributors:
 *     neXtep Softwares - initial API and implementation
 *******************************************************************************/
package com.nextep.designer.util;

import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.collections.map.IdentityMap;

public class IdentitySet<E> implements Set<E> {
    private IdentityMap elts = new IdentityMap();

    @Override
    public boolean add(E e) {
        if (!elts.containsKey(e)) {
            elts.put(e, Boolean.TRUE);
            return true;
        }
        return false;
    }

    @Override
    public boolean addAll(Collection<? extends E> c) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void clear() {
        elts.clear();
    }

    @Override
    public boolean contains(Object o) {
        return elts.containsKey(o);
    }

    @Override
    public boolean containsAll(Collection<?> c) {
        throw new UnsupportedOperationException();
    }

    @Override
    public boolean isEmpty() {
        return elts.isEmpty();
    }

    @SuppressWarnings("unchecked")
    @Override
    public Iterator<E> iterator() {
        return elts.mapIterator();
    }

    @Override
    public boolean remove(Object o) {
        return elts.remove(o) != null;
    }

    @Override
    public boolean removeAll(Collection<?> c) {
        throw new UnsupportedOperationException();
    }

    @Override
    public boolean retainAll(Collection<?> c) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int size() {
        return elts.size();
    }

    @Override
    public Object[] toArray() {
        return elts.keySet().toArray();
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T[] toArray(T[] a) {
        return (T[]) elts.keySet().toArray(a);
    }

}