de.dhke.projects.cutil.collections.cow.CopyOnWriteMultiMap.java Source code

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Here is the source code for de.dhke.projects.cutil.collections.cow.CopyOnWriteMultiMap.java

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/**
 * (c) 2009-2014 Peter Wullinger
 *
 * $Id$
 *
 * Use, modification and restribution of this file are covered by the
 * terms of the Artistic License 2.0.
 *
 * You should have received a copy of the license terms in a file named
 * "LICENSE" together with this software package.
 *
 * Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT
 * HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
 * A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE
 * EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO
 * COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT
 * OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 **/
package de.dhke.projects.cutil.collections.cow;

import de.dhke.projects.cutil.IDecorator;
import de.dhke.projects.cutil.collections.factories.IMultiMapFactory;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.commons.collections15.MultiMap;

/**
 *
 * @author Peter Wullinger <java@dhke.de>
 */
public class CopyOnWriteMultiMap<K, V> implements MultiMap<K, V>, IDecorator<MultiMap<K, V>> {

    private MultiMap<K, V> _baseMap;
    private final IMultiMapFactory<K, V, ? extends MultiMap<K, V>> _factory;
    /* stored key set, entry set, and value collection. Will be created on demand */
    private CopyOnWriteMultiMapKeySet<K, V> _keySet = null;
    private CopyOnWriteMultiMapValueCollection<K, V> _valueCollection = null;
    private CopyOnWriteMultiMapEntrySet<K, V> _entrySet = null;
    private boolean _isWasCopied = false;

    public CopyOnWriteMultiMap(final MultiMap<K, V> baseMap,
            final IMultiMapFactory<K, V, ? extends MultiMap<K, V>> factory) {
        _factory = factory;
        _baseMap = baseMap;
    }

    public boolean copy() {
        if (!_isWasCopied) {
            final MultiMap<K, V> newMap = getFactory().getInstance();
            newMap.putAll(_baseMap);
            _baseMap = newMap;
            _isWasCopied = true;
            return true;
        } else
            return false;
    }

    @Override
    public V remove(final Object key, final Object item) {
        copy();
        return _baseMap.remove(key, item);
    }

    @Override
    public int size(final Object key) {
        return _baseMap.size(key);
    }

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

    @Override
    public Collection<V> get(final Object key) {
        /* if (containsKey(key)) */
        return new CopyOnWriteMultiMapValueCollection<>(this, key);
        /* else
         return null; */
    }

    @Override
    public boolean containsValue(final Object value) {
        return _baseMap.containsValue(value);
    }

    @Override
    public boolean containsValue(final Object key, final Object value) {
        return _baseMap.containsValue(key, value);
    }

    @Override
    public V put(K key, V value) {
        copy();
        return _baseMap.put(key, value);
    }

    @Override
    public Collection<V> remove(final Object key) {
        copy();
        return _baseMap.remove(key);
    }

    @Override
    public Collection<V> values() {
        if (_valueCollection == null)
            _valueCollection = new CopyOnWriteMultiMapValueCollection<>(this);
        return _valueCollection;
    }

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

    @Override
    public boolean containsKey(final Object key) {
        return _baseMap.containsKey(key);
    }

    @Override
    public void putAll(final Map<? extends K, ? extends V> t) {
        copy();
        _baseMap.putAll(t);
    }

    @Override
    public void putAll(final MultiMap<? extends K, ? extends V> t) {
        copy();
        _baseMap.putAll(t);
    }

    @Override
    public boolean putAll(final K key, final Collection<? extends V> values) {
        copy();
        return _baseMap.putAll(key, values);
    }

    @Override
    public Iterator<V> iterator(final Object key) {
        return get(key).iterator();
    }

    @Override
    public void clear() {
        _baseMap = getFactory().getInstance();
        _isWasCopied = true;
    }

    @Override
    public Set<K> keySet() {
        if (_keySet == null)
            _keySet = new CopyOnWriteMultiMapKeySet<>(this);
        return _keySet;
    }

    @Override
    public Map<K, Collection<V>> map() {
        throw new UnsupportedOperationException("Not implemented");
    }

    @Override
    public final MultiMap<K, V> getDecoratee() {
        return _baseMap;
    }

    @Override
    public Set<Entry<K, Collection<V>>> entrySet() {
        if (_entrySet == null)
            _entrySet = new CopyOnWriteMultiMapEntrySet<>(this);
        return _entrySet;
    }

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

    @Override
    public CopyOnWriteMultiMap<K, V> clone() {
        final CopyOnWriteMultiMap<K, V> klone = new CopyOnWriteMultiMap<>(getDecoratee(), getFactory());
        resetWasCopied();
        return klone;
    }

    protected boolean isWasCopied() {
        return _isWasCopied;
    }

    protected void resetWasCopied() {
        _isWasCopied = false;
    }

    /**
     * @return the _factory
     */
    protected IMultiMapFactory<K, V, ? extends MultiMap<K, V>> getFactory() {
        return _factory;
    }
}