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// GenericsNote: Converted.
/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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.collections15.map;
import org.apache.commons.collections15.IterableMap;
import org.apache.commons.collections15.MapIterator;
import org.apache.commons.collections15.keyvalue.MultiKey;
import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* A Map implementation that uses multiple keys to map the value.
*
* This class is the most efficient way to uses multiple keys to map to a value.
* The best way to use this class is via the additional map-style methods.
* These provide get, containsKey, put and
* remove for individual keys which operate without extra object creation.
*
* The additional methods are the main interface of this map.
* As such, you will not normally hold this map in a variable of type Map.
*
* The normal map methods take in and return a {@link MultiKey}.
* If you try to use put() with any other object type a
* ClassCastException is thrown. If you try to use null as
* the key in put() a NullPointerException is thrown.
*
* This map is implemented as a decorator of a AbstractHashedMap which
* enables extra behaviour to be added easily.
*
*
MultiKeyMap.decorate(new LinkedMap()) creates an ordered map.
*
MultiKeyMap.decorate(new LRUMap()) creates an least recently used map.
*
MultiKeyMap.decorate(new ReferenceMap()) creates a garbage collector sensitive map.
*
* Note that IdentityMap and ReferenceIdentityMap are unsuitable
* for use as the key comparison would work on the whole MultiKey, not the elements within.
*
* As an example, consider a least recently used cache that uses a String airline code
* and a Locale to lookup the airline's name:
*
*
* @author Matt Hall, John Watkinson, Stephen Colebourne
* @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $
* @since Commons Collections 3.1
*/
public class MultiKeyMap implements IterableMap, V>, Serializable {
/**
* Serialisation version
*/
private static final long serialVersionUID = -1788199231038721040L;
/**
* The decorated map
*/
protected final AbstractHashedMap, V> map;
//-----------------------------------------------------------------------
/**
* Decorates the specified map to add the MultiKeyMap API and fast query.
* The map must not be null and must be empty.
*
* @param map the map to decorate, not null
* @throws IllegalArgumentException if the map is null or not empty
*/
public static MultiKeyMap decorate(AbstractHashedMap, V> map) {
if (map == null) {
throw new IllegalArgumentException("Map must not be null");
}
if (map.size() > 0) {
throw new IllegalArgumentException("Map must be empty");
}
return new MultiKeyMap(map);
}
//-----------------------------------------------------------------------
/**
* Constructs a new MultiKeyMap that decorates a HashedMap.
*/
public MultiKeyMap() {
super();
map = new HashedMap, V>();
}
/**
* Constructor that decorates the specified map and is called from
* {@link #decorate(AbstractHashedMap)}.
* The map must not be null and should be empty or only contain valid keys.
* This constructor performs no validation.
*
* @param map the map to decorate
*/
protected MultiKeyMap(AbstractHashedMap, V> map) {
super();
this.map = map;
}
//-----------------------------------------------------------------------
/**
* Gets the value mapped to the specified multi-key.
*
* @param keys the keys
* @return the mapped value, null if no match
*/
public V get(K... keys) {
int hashCode = hash(keys);
AbstractHashedMap.HashEntry, V> entry = map.data[map.hashIndex(hashCode, map.data.length)];
while (entry != null) {
if (entry.hashCode == hashCode && isEqualKey(entry, keys)) {
return entry.getValue();
}
entry = entry.next;
}
return null;
}
/**
* Checks whether the map contains the specified multi-key.
*
* @param keys the keys
* @return true if the map contains the key
*/
public boolean containsKey(K... keys) {
int hashCode = hash(keys);
AbstractHashedMap.HashEntry, V> entry = map.data[map.hashIndex(hashCode, map.data.length)];
while (entry != null) {
if (entry.hashCode == hashCode && isEqualKey(entry, keys)) {
return true;
}
entry = entry.next;
}
return false;
}
/**
* For backwards compatibility, makes a call to the new varargs {@link MultiKeyMap#putMultiKey}
*/
public V put(K key1, K key2, V value) {
return putMultiKey(value, key1, key2);
}
/**
* For backwards compatibility, makes a call to the new varargs {@link MultiKeyMap#putMultiKey}
*/
public V put(K key1, K key2, K key3, V value) {
return putMultiKey(value, key1, key2, key3);
}
/**
* For backwards compatibility, makes a call to the new varargs {@link MultiKeyMap#putMultiKey}
*/
public V put(K key1, K key2, K key3, K key4, V value) {
return putMultiKey(value, key1, key2, key3, key4);
}
/**
* For backwards compatibility, makes a call to the new varargs {@link MultiKeyMap#putMultiKey}
*/
public V put(K key1, K key2, K key3, K key4, K key5, V value) {
return putMultiKey(value, key1, key2, key3, key4, key5);
}
/**
* Stores the value against the specified multi-key.
*
* @param value the value to store
* @param keys the keys
* @return the value previously mapped to this combined key, null if none
*/
public V putMultiKey(V value, K... keys) {
int hashCode = hash(keys);
int index = map.hashIndex(hashCode, map.data.length);
AbstractHashedMap.HashEntry, V> entry = map.data[index];
while (entry != null) {
if (entry.hashCode == hashCode && isEqualKey(entry, keys)) {
V oldValue = entry.getValue();
map.updateEntry(entry, value);
return oldValue;
}
entry = entry.next;
}
map.addMapping(index, hashCode, new MultiKey(keys), value);
return null;
}
/**
* Removes the specified multi-key from this map.
*
* @param keys the keys
* @return the value mapped to the removed key, null if key not in map
*/
public Object remove(K... keys) {
int hashCode = hash(keys);
int index = map.hashIndex(hashCode, map.data.length);
AbstractHashedMap.HashEntry, V> entry = map.data[index];
AbstractHashedMap.HashEntry, V> previous = null;
while (entry != null) {
if (entry.hashCode == hashCode && isEqualKey(entry, keys)) {
Object oldValue = entry.getValue();
map.removeMapping(entry, index, previous);
return oldValue;
}
previous = entry;
entry = entry.next;
}
return null;
}
/**
* Gets the hash code for the specified multi-key.
*
* @param keys the keys
* @return the hash code
*/
protected int hash(K... keys) {
int h = 0;
for (int i = 0; i < keys.length; i++) {
K key = keys[i];
if (key != null) {
h ^= key.hashCode();
}
}
h += ~(h << 9);
h ^= (h >>> 14);
h += (h << 4);
h ^= (h >>> 10);
return h;
}
/**
* Is the key equal to the combined key.
*
* @param entry the entry to compare to
* @param keys the keys
* @return true if the key matches
*/
protected boolean isEqualKey(AbstractHashedMap.HashEntry, V> entry, K... keys) {
MultiKey multi = (MultiKey) entry.getKey();
if (multi.size() != keys.length) {
return false;
} else {
for (int i = 0; i < keys.length; i++) {
K key = keys[i];
if ((key == null ? multi.getKey(i) != null : !key.equals(multi.getKey(i)))) {
return false;
}
}
}
return true;
}
//-----------------------------------------------------------------------
/**
* Removes all mappings where the first key is that specified.
*
* This method removes all the mappings where the MultiKey
* has one or more keys, and the first matches that specified.
*
* @param key1 the first key
* @return true if any elements were removed
*/
public boolean removeAll(Object key1) {
boolean modified = false;
MapIterator it = mapIterator();
while (it.hasNext()) {
MultiKey multi = (MultiKey) it.next();
if (multi.size() >= 1 && (key1 == null ? multi.getKey(0) == null : key1.equals(multi.getKey(0)))) {
it.remove();
modified = true;
}
}
return modified;
}
/**
* Removes all mappings where the first two keys are those specified.
*
* This method removes all the mappings where the MultiKey
* has two or more keys, and the first two match those specified.
*
* @param key1 the first key
* @param key2 the second key
* @return true if any elements were removed
*/
public boolean removeAll(Object key1, Object key2) {
boolean modified = false;
MapIterator it = mapIterator();
while (it.hasNext()) {
MultiKey multi = (MultiKey) it.next();
if (multi.size() >= 2 && (key1 == null ? multi.getKey(0) == null : key1.equals(multi.getKey(0))) && (key2 == null ? multi.getKey(1) == null : key2.equals(multi.getKey(1)))) {
it.remove();
modified = true;
}
}
return modified;
}
/**
* Removes all mappings where the first three keys are those specified.
*
* This method removes all the mappings where the MultiKey
* has three or more keys, and the first three match those specified.
*
* @param key1 the first key
* @param key2 the second key
* @param key3 the third key
* @return true if any elements were removed
*/
public boolean removeAll(Object key1, Object key2, Object key3) {
boolean modified = false;
MapIterator it = mapIterator();
while (it.hasNext()) {
MultiKey multi = (MultiKey) it.next();
if (multi.size() >= 3 && (key1 == null ? multi.getKey(0) == null : key1.equals(multi.getKey(0))) && (key2 == null ? multi.getKey(1) == null : key2.equals(multi.getKey(1))) && (key3 == null ? multi.getKey(2) == null : key3.equals(multi.getKey(2)))) {
it.remove();
modified = true;
}
}
return modified;
}
/**
* Removes all mappings where the first four keys are those specified.
*
* This method removes all the mappings where the MultiKey
* has four or more keys, and the first four match those specified.
*
* @param key1 the first key
* @param key2 the second key
* @param key3 the third key
* @param key4 the fourth key
* @return true if any elements were removed
*/
public boolean removeAll(Object key1, Object key2, Object key3, Object key4) {
boolean modified = false;
MapIterator it = mapIterator();
while (it.hasNext()) {
MultiKey multi = (MultiKey) it.next();
if (multi.size() >= 4 && (key1 == null ? multi.getKey(0) == null : key1.equals(multi.getKey(0))) && (key2 == null ? multi.getKey(1) == null : key2.equals(multi.getKey(1))) && (key3 == null ? multi.getKey(2) == null : key3.equals(multi.getKey(2))) && (key4 == null ? multi.getKey(3) == null : key4.equals(multi.getKey(3)))) {
it.remove();
modified = true;
}
}
return modified;
}
//-----------------------------------------------------------------------
/**
* Check to ensure that input keys are valid MultiKey objects.
*
* @param key the key to check
*/
protected void checkKey(Object key) {
if (key == null) {
throw new NullPointerException("Key must not be null");
}
}
/**
* Clones the map without cloning the keys or values.
*
* @return a shallow clone
*/
public Object clone() {
return new MultiKeyMap((AbstractHashedMap) map.clone());
}
/**
* Puts the key and value into the map, where the key must be a non-null
* MultiKey object.
*
* @param key the non-null MultiKey object
* @param value the value to store
* @return the previous value for the key
* @throws NullPointerException if the key is null
* @throws ClassCastException if the key is not a MultiKey
*/
public V put(MultiKey key, V value) {
checkKey(key);
return map.put(key, value);
}
/**
* Puts all the keys and values into this map.
* Each key must be non-null and a MultiKey object.
*
* @param mapToCopy the map to copy in.
* @throws NullPointerException if the mapToCopy or any key within is null
* @throws ClassCastException if any key is not a MultiKey
*/
public void putAll(Map, ? extends V> mapToCopy) {
for (Iterator it = mapToCopy.keySet().iterator(); it.hasNext();) {
Object key = it.next();
checkKey(key);
}
map.putAll(mapToCopy);
}
//-----------------------------------------------------------------------
public MapIterator mapIterator() {
return map.mapIterator();
}
public int size() {
return map.size();
}
public boolean isEmpty() {
return map.isEmpty();
}
public boolean containsKey(Object key) {
return map.containsKey(key);
}
public boolean containsValue(Object value) {
return map.containsValue(value);
}
public V get(Object key) {
return map.get(key);
}
public V remove(Object key) {
return map.remove(key);
}
public void clear() {
map.clear();
}
public Set keySet() {
return map.keySet();
}
public Collection values() {
return map.values();
}
public Set entrySet() {
return map.entrySet();
}
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
return map.equals(obj);
}
public int hashCode() {
return map.hashCode();
}
public String toString() {
return map.toString();
}
}
