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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.collections4.bidimap;

import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import org.apache.commons.collections4.BidiMap;
import org.apache.commons.collections4.MapIterator;
import org.apache.commons.collections4.ResettableIterator;
import org.apache.commons.collections4.collection.AbstractCollectionDecorator;
import org.apache.commons.collections4.iterators.AbstractIteratorDecorator;
import org.apache.commons.collections4.keyvalue.AbstractMapEntryDecorator;

/**
 * Abstract {@link BidiMap} implemented using two maps.
 * 

* An implementation can be written simply by implementing the * {@link #createBidiMap(Map, Map, BidiMap)} method. * * @see DualHashBidiMap * @see DualTreeBidiMap * @since 3.0 * @version $Id: AbstractDualBidiMap.java 1683951 2015-06-06 20:19:03Z tn $ */ public abstract class AbstractDualBidiMap implements BidiMap { /** * Normal delegate map. */ transient Map normalMap; /** * Reverse delegate map. */ transient Map reverseMap; /** * Inverse view of this map. */ transient BidiMap inverseBidiMap = null; /** * View of the keys. */ transient Set keySet = null; /** * View of the values. */ transient Set values = null; /** * View of the entries. */ transient Set> entrySet = null; /** * Creates an empty map, initialised by createMap. *

* This constructor remains in place for deserialization. * All other usage is deprecated in favour of * {@link #AbstractDualBidiMap(Map, Map)}. */ protected AbstractDualBidiMap() { super(); } /** * Creates an empty map using the two maps specified as storage. *

* The two maps must be a matching pair, normal and reverse. * They will typically both be empty. *

* Neither map is validated, so nulls may be passed in. * If you choose to do this then the subclass constructor must populate * the maps[] instance variable itself. * * @param normalMap the normal direction map * @param reverseMap the reverse direction map * @since 3.1 */ protected AbstractDualBidiMap(final Map normalMap, final Map reverseMap) { super(); this.normalMap = normalMap; this.reverseMap = reverseMap; } /** * Constructs a map that decorates the specified maps, * used by the subclass createBidiMap implementation. * * @param normalMap the normal direction map * @param reverseMap the reverse direction map * @param inverseBidiMap the inverse BidiMap */ protected AbstractDualBidiMap(final Map normalMap, final Map reverseMap, final BidiMap inverseBidiMap) { super(); this.normalMap = normalMap; this.reverseMap = reverseMap; this.inverseBidiMap = inverseBidiMap; } /** * Creates a new instance of the subclass. * * @param normalMap the normal direction map * @param reverseMap the reverse direction map * @param inverseMap this map, which is the inverse in the new map * @return the inverse map */ protected abstract BidiMap createBidiMap(Map normalMap, Map reverseMap, BidiMap inverseMap); // Map delegation //----------------------------------------------------------------------- @Override public V get(final Object key) { return normalMap.get(key); } @Override public int size() { return normalMap.size(); } @Override public boolean isEmpty() { return normalMap.isEmpty(); } @Override public boolean containsKey(final Object key) { return normalMap.containsKey(key); } @Override public boolean equals(final Object obj) { return normalMap.equals(obj); } @Override public int hashCode() { return normalMap.hashCode(); } @Override public String toString() { return normalMap.toString(); } // BidiMap changes //----------------------------------------------------------------------- @Override public V put(final K key, final V value) { if (normalMap.containsKey(key)) { reverseMap.remove(normalMap.get(key)); } if (reverseMap.containsKey(value)) { normalMap.remove(reverseMap.get(value)); } final V obj = normalMap.put(key, value); reverseMap.put(value, key); return obj; } @Override public void putAll(final Map map) { for (final Map.Entry entry : map.entrySet()) { put(entry.getKey(), entry.getValue()); } } @Override public V remove(final Object key) { V value = null; if (normalMap.containsKey(key)) { value = normalMap.remove(key); reverseMap.remove(value); } return value; } @Override public void clear() { normalMap.clear(); reverseMap.clear(); } @Override public boolean containsValue(final Object value) { return reverseMap.containsKey(value); } // BidiMap //----------------------------------------------------------------------- /** * Obtains a MapIterator over the map. * The iterator implements ResetableMapIterator. * This implementation relies on the entrySet iterator. *

* The setValue() methods only allow a new value to be set. * If the value being set is already in the map, an IllegalArgumentException * is thrown (as setValue cannot change the size of the map). * * @return a map iterator */ @Override public MapIterator mapIterator() { return new BidiMapIterator(this); } @Override public K getKey(final Object value) { return reverseMap.get(value); } @Override public K removeValue(final Object value) { K key = null; if (reverseMap.containsKey(value)) { key = reverseMap.remove(value); normalMap.remove(key); } return key; } @Override public BidiMap inverseBidiMap() { if (inverseBidiMap == null) { inverseBidiMap = createBidiMap(reverseMap, normalMap, this); } return inverseBidiMap; } // Map views //----------------------------------------------------------------------- /** * Gets a keySet view of the map. * Changes made on the view are reflected in the map. * The set supports remove and clear but not add. * * @return the keySet view */ @Override public Set keySet() { if (keySet == null) { keySet = new KeySet(this); } return keySet; } /** * Creates a key set iterator. * Subclasses can override this to return iterators with different properties. * * @param iterator the iterator to decorate * @return the keySet iterator */ protected Iterator createKeySetIterator(final Iterator iterator) { return new KeySetIterator(iterator, this); } /** * Gets a values view of the map. * Changes made on the view are reflected in the map. * The set supports remove and clear but not add. * * @return the values view */ @Override public Set values() { if (values == null) { values = new Values(this); } return values; } /** * Creates a values iterator. * Subclasses can override this to return iterators with different properties. * * @param iterator the iterator to decorate * @return the values iterator */ protected Iterator createValuesIterator(final Iterator iterator) { return new ValuesIterator(iterator, this); } /** * Gets an entrySet view of the map. * Changes made on the set are reflected in the map. * The set supports remove and clear but not add. *

* The Map Entry setValue() method only allow a new value to be set. * If the value being set is already in the map, an IllegalArgumentException * is thrown (as setValue cannot change the size of the map). * * @return the entrySet view */ @Override public Set> entrySet() { if (entrySet == null) { entrySet = new EntrySet(this); } return entrySet; } /** * Creates an entry set iterator. * Subclasses can override this to return iterators with different properties. * * @param iterator the iterator to decorate * @return the entrySet iterator */ protected Iterator> createEntrySetIterator(final Iterator> iterator) { return new EntrySetIterator(iterator, this); } //----------------------------------------------------------------------- /** * Inner class View. */ protected static abstract class View extends AbstractCollectionDecorator { /** Generated serial version ID. */ private static final long serialVersionUID = 4621510560119690639L; /** The parent map */ protected final AbstractDualBidiMap parent; /** * Constructs a new view of the BidiMap. * * @param coll the collection view being decorated * @param parent the parent BidiMap */ protected View(final Collection coll, final AbstractDualBidiMap parent) { super(coll); this.parent = parent; } @Override public boolean equals(final Object object) { return object == this || decorated().equals(object); } @Override public int hashCode() { return decorated().hashCode(); } @Override public boolean removeAll(final Collection coll) { if (parent.isEmpty() || coll.isEmpty()) { return false; } boolean modified = false; final Iterator it = coll.iterator(); while (it.hasNext()) { modified |= remove(it.next()); } return modified; } /** * {@inheritDoc} *

* This implementation iterates over the elements of this bidi map, checking each element in * turn to see if it's contained in coll. If it's not contained, it's removed * from this bidi map. As a consequence, it is advised to use a collection type for * coll that provides a fast (e.g. O(1)) implementation of * {@link Collection#contains(Object)}. */ @Override public boolean retainAll(final Collection coll) { if (parent.isEmpty()) { return false; } if (coll.isEmpty()) { parent.clear(); return true; } boolean modified = false; final Iterator it = iterator(); while (it.hasNext()) { if (coll.contains(it.next()) == false) { it.remove(); modified = true; } } return modified; } @Override public void clear() { parent.clear(); } } //----------------------------------------------------------------------- /** * Inner class KeySet. */ protected static class KeySet extends View implements Set { /** Serialization version */ private static final long serialVersionUID = -7107935777385040694L; /** * Constructs a new view of the BidiMap. * * @param parent the parent BidiMap */ @SuppressWarnings("unchecked") protected KeySet(final AbstractDualBidiMap parent) { super(parent.normalMap.keySet(), (AbstractDualBidiMap) parent); } @Override public Iterator iterator() { return parent.createKeySetIterator(super.iterator()); } @Override public boolean contains(final Object key) { return parent.normalMap.containsKey(key); } @Override public boolean remove(final Object key) { if (parent.normalMap.containsKey(key)) { final Object value = parent.normalMap.remove(key); parent.reverseMap.remove(value); return true; } return false; } } /** * Inner class KeySetIterator. */ protected static class KeySetIterator extends AbstractIteratorDecorator { /** The parent map */ protected final AbstractDualBidiMap parent; /** The last returned key */ protected K lastKey = null; /** Whether remove is allowed at present */ protected boolean canRemove = false; /** * Constructor. * @param iterator the iterator to decorate * @param parent the parent map */ protected KeySetIterator(final Iterator iterator, final AbstractDualBidiMap parent) { super(iterator); this.parent = parent; } @Override public K next() { lastKey = super.next(); canRemove = true; return lastKey; } @Override public void remove() { if (canRemove == false) { throw new IllegalStateException("Iterator remove() can only be called once after next()"); } final Object value = parent.normalMap.get(lastKey); super.remove(); parent.reverseMap.remove(value); lastKey = null; canRemove = false; } } //----------------------------------------------------------------------- /** * Inner class Values. */ protected static class Values extends View implements Set { /** Serialization version */ private static final long serialVersionUID = 4023777119829639864L; /** * Constructs a new view of the BidiMap. * * @param parent the parent BidiMap */ @SuppressWarnings("unchecked") protected Values(final AbstractDualBidiMap parent) { super(parent.normalMap.values(), (AbstractDualBidiMap) parent); } @Override public Iterator iterator() { return parent.createValuesIterator(super.iterator()); } @Override public boolean contains(final Object value) { return parent.reverseMap.containsKey(value); } @Override public boolean remove(final Object value) { if (parent.reverseMap.containsKey(value)) { final Object key = parent.reverseMap.remove(value); parent.normalMap.remove(key); return true; } return false; } } /** * Inner class ValuesIterator. */ protected static class ValuesIterator extends AbstractIteratorDecorator { /** The parent map */ protected final AbstractDualBidiMap parent; /** The last returned value */ protected V lastValue = null; /** Whether remove is allowed at present */ protected boolean canRemove = false; /** * Constructor. * @param iterator the iterator to decorate * @param parent the parent map */ @SuppressWarnings("unchecked") protected ValuesIterator(final Iterator iterator, final AbstractDualBidiMap parent) { super(iterator); this.parent = (AbstractDualBidiMap) parent; } @Override public V next() { lastValue = super.next(); canRemove = true; return lastValue; } @Override public void remove() { if (canRemove == false) { throw new IllegalStateException("Iterator remove() can only be called once after next()"); } super.remove(); // removes from maps[0] parent.reverseMap.remove(lastValue); lastValue = null; canRemove = false; } } //----------------------------------------------------------------------- /** * Inner class EntrySet. */ protected static class EntrySet extends View> implements Set> { /** Serialization version */ private static final long serialVersionUID = 4040410962603292348L; /** * Constructs a new view of the BidiMap. * * @param parent the parent BidiMap */ protected EntrySet(final AbstractDualBidiMap parent) { super(parent.normalMap.entrySet(), parent); } @Override public Iterator> iterator() { return parent.createEntrySetIterator(super.iterator()); } @Override public boolean remove(final Object obj) { if (obj instanceof Map.Entry == false) { return false; } final Map.Entry entry = (Map.Entry) obj; final Object key = entry.getKey(); if (parent.containsKey(key)) { final V value = parent.normalMap.get(key); if (value == null ? entry.getValue() == null : value.equals(entry.getValue())) { parent.normalMap.remove(key); parent.reverseMap.remove(value); return true; } } return false; } } /** * Inner class EntrySetIterator. */ protected static class EntrySetIterator extends AbstractIteratorDecorator> { /** The parent map */ protected final AbstractDualBidiMap parent; /** The last returned entry */ protected Map.Entry last = null; /** Whether remove is allowed at present */ protected boolean canRemove = false; /** * Constructor. * @param iterator the iterator to decorate * @param parent the parent map */ protected EntrySetIterator(final Iterator> iterator, final AbstractDualBidiMap parent) { super(iterator); this.parent = parent; } @Override public Map.Entry next() { last = new MapEntry(super.next(), parent); canRemove = true; return last; } @Override public void remove() { if (canRemove == false) { throw new IllegalStateException("Iterator remove() can only be called once after next()"); } // store value as remove may change the entry in the decorator (eg.TreeMap) final Object value = last.getValue(); super.remove(); parent.reverseMap.remove(value); last = null; canRemove = false; } } /** * Inner class MapEntry. */ protected static class MapEntry extends AbstractMapEntryDecorator { /** The parent map */ protected final AbstractDualBidiMap parent; /** * Constructor. * @param entry the entry to decorate * @param parent the parent map */ protected MapEntry(final Map.Entry entry, final AbstractDualBidiMap parent) { super(entry); this.parent = parent; } @Override public V setValue(final V value) { final K key = MapEntry.this.getKey(); if (parent.reverseMap.containsKey(value) && parent.reverseMap.get(value) != key) { throw new IllegalArgumentException( "Cannot use setValue() when the object being set is already in the map"); } parent.put(key, value); return super.setValue(value); } } /** * Inner class MapIterator. */ protected static class BidiMapIterator implements MapIterator, ResettableIterator { /** The parent map */ protected final AbstractDualBidiMap parent; /** The iterator being wrapped */ protected Iterator> iterator; /** The last returned entry */ protected Map.Entry last = null; /** Whether remove is allowed at present */ protected boolean canRemove = false; /** * Constructor. * @param parent the parent map */ protected BidiMapIterator(final AbstractDualBidiMap parent) { super(); this.parent = parent; this.iterator = parent.normalMap.entrySet().iterator(); } @Override public boolean hasNext() { return iterator.hasNext(); } @Override public K next() { last = iterator.next(); canRemove = true; return last.getKey(); } @Override public void remove() { if (canRemove == false) { throw new IllegalStateException("Iterator remove() can only be called once after next()"); } // store value as remove may change the entry in the decorator (eg.TreeMap) final V value = last.getValue(); iterator.remove(); parent.reverseMap.remove(value); last = null; canRemove = false; } @Override public K getKey() { if (last == null) { throw new IllegalStateException( "Iterator getKey() can only be called after next() and before remove()"); } return last.getKey(); } @Override public V getValue() { if (last == null) { throw new IllegalStateException( "Iterator getValue() can only be called after next() and before remove()"); } return last.getValue(); } @Override public V setValue(final V value) { if (last == null) { throw new IllegalStateException( "Iterator setValue() can only be called after next() and before remove()"); } if (parent.reverseMap.containsKey(value) && parent.reverseMap.get(value) != last.getKey()) { throw new IllegalArgumentException( "Cannot use setValue() when the object being set is already in the map"); } return parent.put(last.getKey(), value); } @Override public void reset() { iterator = parent.normalMap.entrySet().iterator(); last = null; canRemove = false; } @Override public String toString() { if (last != null) { return "MapIterator[" + getKey() + "=" + getValue() + "]"; } return "MapIterator[]"; } } }





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