uniol.apt.adt.CollectionToUnmodifiableSetAdapter.java Source code

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Here is the source code for uniol.apt.adt.CollectionToUnmodifiableSetAdapter.java

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/*-
 * APT - Analysis of Petri Nets and labeled Transition systems
 * Copyright (C) 2015  Uli Schlachter
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package uniol.apt.adt;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;

import static org.apache.commons.collections4.iterators.UnmodifiableIterator.unmodifiableIterator;

/**
 * Given a collection which really behaves like a set (read: has no duplicate entries), implement a read-only set.
 * @param <E> The type of elements of the set.
 * @author Uli Schlachter
 */
public class CollectionToUnmodifiableSetAdapter<E> extends AbstractSet<E> {
    private final Collection<E> collection;

    /**
     * Create a new adapter for the given Collection. This does not create a copy of the collection, but instead
     * behaves as a view into that collection.
     * @param c The collection to adapt into a set.
     */
    public CollectionToUnmodifiableSetAdapter(Collection<E> c) {
        this.collection = Collections.unmodifiableCollection(c);
    }

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

    @Override
    public boolean containsAll(Collection<?> c) {
        return collection.containsAll(c);
    }

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

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

    @Override
    public Iterator<E> iterator() {
        return unmodifiableIterator(collection.iterator());
    }

    @Override
    public String toString() {
        return collection.toString();
    }

    @Override
    public boolean equals(Object o) {
        return collection.equals(o);
    }

    @Override
    public int hashCode() {
        return collection.hashCode();
    }

    // We could also implement toArray(), but is that really worth it?
}

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