de.dhke.projects.cutil.collections.aspect.AspectMultiMapEntrySet.java Source code

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Here is the source code for de.dhke.projects.cutil.collections.aspect.AspectMultiMapEntrySet.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.aspect;

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;
import org.apache.commons.collections15.keyvalue.DefaultMapEntry;

/**
 *
 * @param <K>
 * @param <V>
 * @param <M>
 * @author Peter Wullinger <java@dhke.de>
 */
public class AspectMultiMapEntrySet<K, V, M extends MultiMap<K, V>> implements Set<Map.Entry<K, Collection<V>>> {

    private final AspectMultiMap<K, V, M> _aspectMap;
    private final Set<Map.Entry<K, Collection<V>>> _entrySet;

    protected AspectMultiMapEntrySet(final AspectMultiMap<K, V, M> aspectMap) {
        _aspectMap = aspectMap;
        _entrySet = _aspectMap.getDecoratee().entrySet();
    }

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

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

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

    @Override
    public Iterator<Entry<K, Collection<V>>> iterator() {
        return new Itr();
    }

    @Override
    public Object[] toArray() {
        /* XXX - this may be a loophole */
        return _entrySet.toArray();
    }

    @Override
    public <T> T[] toArray(final T[] a) {
        /* XXX - this may be a loophole */
        return _entrySet.toArray(a);
    }

    @Override
    public boolean add(final Entry<K, Collection<V>> e) {
        throw new UnsupportedOperationException("Cannot add to entry set");
    }

    @Override
    public boolean remove(final Object o) {
        if (o instanceof Map.Entry) {
            final Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
            if (_aspectMap.containsKey(entry.getKey())) {
                Collection<V> values = _aspectMap.get(entry.getKey());
                if (values.equals(entry.getValue())) {
                    _aspectMap.remove(entry.getKey());
                    return true;
                }
            }
        }
        return false;
    }

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

    @Override
    public boolean addAll(final Collection<? extends Entry<K, Collection<V>>> c) {
        throw new UnsupportedOperationException("Cannot add to entry set.");
    }

    @Override
    public boolean retainAll(final Collection<?> c) {
        return batchRemove(c, true);
    }

    @Override
    public boolean removeAll(final Collection<?> c) {
        return batchRemove(c, false);
    }

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

    private boolean batchRemove(Collection<?> c, boolean retain) {
        for (Map.Entry<K, Collection<V>> entry : _entrySet) {
            if (c.contains(entry) != retain) {
                for (V value : entry.getValue()) {
                    final Map.Entry<K, V> evEntry = new DefaultMapEntry<>(entry.getKey(), value);
                    _aspectMap.notifyBeforeElementRemoved(_aspectMap, evEntry);
                }
            }
        }

        final Iterator<Map.Entry<K, Collection<V>>> iter = _entrySet.iterator();
        boolean wasRemoved = false;
        while (iter.hasNext()) {
            Map.Entry<K, Collection<V>> entry = iter.next();
            if (c.contains(entry) != retain) {
                iter.remove();
                wasRemoved = true;
                for (V value : entry.getValue()) {
                    Map.Entry<K, V> evEntry = new DefaultMapEntry<>(entry.getKey(), value);
                    _aspectMap.notifyAfterElementRemoved(_aspectMap, evEntry);
                }
            }
        }
        return wasRemoved;
    }

    private class Itr implements Iterator<Map.Entry<K, Collection<V>>> {
        Iterator<K> _keyIterator;
        private Map.Entry<K, Collection<V>> _current = null;

        protected Itr() {
            _keyIterator = _aspectMap.keySet().iterator();
        }

        @Override
        public boolean hasNext() {
            return _keyIterator.hasNext();
        }

        @Override
        public Entry<K, Collection<V>> next() {
            K key = _keyIterator.next();
            Collection<V> value = _aspectMap.get(key);
            _current = new DefaultMapEntry<>(key, value);
            return _current;
        }

        @Override
        public void remove() {
            _keyIterator.remove();
        }
    }
}