| /* |
| * Copyright 2003-2004 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.collections.map; |
| |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.apache.commons.collections.CollectionUtils; |
| import org.apache.commons.collections.collection.CompositeCollection; |
| import org.apache.commons.collections.set.CompositeSet; |
| |
| /** |
| * Decorates a map of other maps to provide a single unified view. |
| * <p> |
| * Changes made to this map will actually be made on the decorated map. |
| * Add and remove operations require the use of a pluggable strategy. If no |
| * strategy is provided then add and remove are unsupported. |
| * <p> |
| * <strong>Note that CompositeMap is not synchronized and is not thread-safe.</strong> |
| * If you wish to use this map from multiple threads concurrently, you must use |
| * appropriate synchronization. The simplest approach is to wrap this map |
| * using {@link java.util.Collections#synchronizedMap(Map)}. This class may throw |
| * exceptions when accessed by concurrent threads without synchronization. |
| * |
| * @since Commons Collections 3.0 |
| * @version $Revision: 1.1 $ $Date: 2009/05/27 22:16:29 $ |
| * |
| * @author Brian McCallister |
| */ |
| public class CompositeMap implements Map { |
| |
| /** Array of all maps in the composite */ |
| private Map[] composite; |
| |
| /** Handle mutation operations */ |
| private MapMutator mutator; |
| |
| /** |
| * Create a new, empty, CompositeMap. |
| */ |
| public CompositeMap() { |
| this(new Map[]{}, null); |
| } |
| |
| /** |
| * Create a new CompositeMap with two composited Map instances. |
| * |
| * @param one the first Map to be composited |
| * @param two the second Map to be composited |
| * @throws IllegalArgumentException if there is a key collision |
| */ |
| public CompositeMap(Map one, Map two) { |
| this(new Map[]{one, two}, null); |
| } |
| |
| /** |
| * Create a new CompositeMap with two composited Map instances. |
| * |
| * @param one the first Map to be composited |
| * @param two the second Map to be composited |
| * @param mutator MapMutator to be used for mutation operations |
| */ |
| public CompositeMap(Map one, Map two, MapMutator mutator) { |
| this(new Map[]{one, two}, mutator); |
| } |
| |
| /** |
| * Create a new CompositeMap which composites all of the Map instances in the |
| * argument. It copies the argument array, it does not use it directly. |
| * |
| * @param composite the Maps to be composited |
| * @throws IllegalArgumentException if there is a key collision |
| */ |
| public CompositeMap(Map[] composite) { |
| this(composite, null); |
| } |
| |
| /** |
| * Create a new CompositeMap which composites all of the Map instances in the |
| * argument. It copies the argument array, it does not use it directly. |
| * |
| * @param composite Maps to be composited |
| * @param mutator MapMutator to be used for mutation operations |
| */ |
| public CompositeMap(Map[] composite, MapMutator mutator) { |
| this.mutator = mutator; |
| this.composite = new Map[0]; |
| for (int i = composite.length - 1; i >= 0; --i) { |
| this.addComposited(composite[i]); |
| } |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Specify the MapMutator to be used by mutation operations. |
| * |
| * @param mutator the MapMutator to be used for mutation delegation |
| */ |
| public void setMutator(MapMutator mutator) { |
| this.mutator = mutator; |
| } |
| |
| /** |
| * Add an additional Map to the composite. |
| * |
| * @param map the Map to be added to the composite |
| * @throws IllegalArgumentException if there is a key collision and there is no |
| * MapMutator set to handle it. |
| */ |
| public synchronized void addComposited(Map map) throws IllegalArgumentException { |
| for (int i = composite.length - 1; i >= 0; --i) { |
| Collection intersect = CollectionUtils.intersection(this.composite[i].keySet(), map.keySet()); |
| if (intersect.size() != 0) { |
| if (this.mutator == null) { |
| throw new IllegalArgumentException("Key collision adding Map to CompositeMap"); |
| } |
| else { |
| this.mutator.resolveCollision(this, this.composite[i], map, intersect); |
| } |
| } |
| } |
| Map[] temp = new Map[this.composite.length + 1]; |
| System.arraycopy(this.composite, 0, temp, 0, this.composite.length); |
| temp[temp.length - 1] = map; |
| this.composite = temp; |
| } |
| |
| /** |
| * Remove a Map from the composite. |
| * |
| * @param map the Map to be removed from the composite |
| * @return The removed Map or <code>null</code> if map is not in the composite |
| */ |
| public synchronized Map removeComposited(Map map) { |
| int size = this.composite.length; |
| for (int i = 0; i < size; ++i) { |
| if (this.composite[i].equals(map)) { |
| Map[] temp = new Map[size - 1]; |
| System.arraycopy(this.composite, 0, temp, 0, i); |
| System.arraycopy(this.composite, i + 1, temp, i, size - i - 1); |
| this.composite = temp; |
| return map; |
| } |
| } |
| return null; |
| } |
| |
| //----------------------------------------------------------------------- |
| /** |
| * Calls <code>clear()</code> on all composited Maps. |
| * |
| * @throws UnsupportedOperationException if any of the composited Maps do not support clear() |
| */ |
| public void clear() { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| this.composite[i].clear(); |
| } |
| } |
| |
| /** |
| * Returns <tt>true</tt> if this map contains a mapping for the specified |
| * key. More formally, returns <tt>true</tt> if and only if |
| * this map contains at a mapping for a key <tt>k</tt> such that |
| * <tt>(key==null ? k==null : key.equals(k))</tt>. (There can be |
| * at most one such mapping.) |
| * |
| * @param key key whose presence in this map is to be tested. |
| * @return <tt>true</tt> if this map contains a mapping for the specified |
| * key. |
| * |
| * @throws ClassCastException if the key is of an inappropriate type for |
| * this map (optional). |
| * @throws NullPointerException if the key is <tt>null</tt> and this map |
| * does not not permit <tt>null</tt> keys (optional). |
| */ |
| public boolean containsKey(Object key) { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| if (this.composite[i].containsKey(key)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Returns <tt>true</tt> if this map maps one or more keys to the |
| * specified value. More formally, returns <tt>true</tt> if and only if |
| * this map contains at least one mapping to a value <tt>v</tt> such that |
| * <tt>(value==null ? v==null : value.equals(v))</tt>. This operation |
| * will probably require time linear in the map size for most |
| * implementations of the <tt>Map</tt> interface. |
| * |
| * @param value value whose presence in this map is to be tested. |
| * @return <tt>true</tt> if this map maps one or more keys to the |
| * specified value. |
| * @throws ClassCastException if the value is of an inappropriate type for |
| * this map (optional). |
| * @throws NullPointerException if the value is <tt>null</tt> and this map |
| * does not not permit <tt>null</tt> values (optional). |
| */ |
| public boolean containsValue(Object value) { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| if (this.composite[i].containsValue(value)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Returns a set view of the mappings contained in this map. Each element |
| * in the returned set is a <code>Map.Entry</code>. The set is backed by the |
| * map, so changes to the map are reflected in the set, and vice-versa. |
| * If the map is modified while an iteration over the set is in progress, |
| * the results of the iteration are undefined. The set supports element |
| * removal, which removes the corresponding mapping from the map, via the |
| * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, <tt>removeAll</tt>, |
| * <tt>retainAll</tt> and <tt>clear</tt> operations. It does not support |
| * the <tt>add</tt> or <tt>addAll</tt> operations. |
| * <p> |
| * This implementation returns a <code>CompositeSet</code> which |
| * composites the entry sets from all of the composited maps. |
| * |
| * @see CompositeSet |
| * @return a set view of the mappings contained in this map. |
| */ |
| public Set entrySet() { |
| CompositeSet entries = new CompositeSet(); |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| entries.addComposited(this.composite[i].entrySet()); |
| } |
| return entries; |
| } |
| |
| /** |
| * Returns the value to which this map maps the specified key. Returns |
| * <tt>null</tt> if the map contains no mapping for this key. A return |
| * value of <tt>null</tt> does not <i>necessarily</i> indicate that the |
| * map contains no mapping for the key; it's also possible that the map |
| * explicitly maps the key to <tt>null</tt>. The <tt>containsKey</tt> |
| * operation may be used to distinguish these two cases. |
| * |
| * <p>More formally, if this map contains a mapping from a key |
| * <tt>k</tt> to a value <tt>v</tt> such that <tt>(key==null ? k==null : |
| * key.equals(k))</tt>, then this method returns <tt>v</tt>; otherwise |
| * it returns <tt>null</tt>. (There can be at most one such mapping.) |
| * |
| * @param key key whose associated value is to be returned. |
| * @return the value to which this map maps the specified key, or |
| * <tt>null</tt> if the map contains no mapping for this key. |
| * |
| * @throws ClassCastException if the key is of an inappropriate type for |
| * this map (optional). |
| * @throws NullPointerException key is <tt>null</tt> and this map does not |
| * not permit <tt>null</tt> keys (optional). |
| * |
| * @see #containsKey(Object) |
| */ |
| public Object get(Object key) { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| if (this.composite[i].containsKey(key)) { |
| return this.composite[i].get(key); |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Returns <tt>true</tt> if this map contains no key-value mappings. |
| * |
| * @return <tt>true</tt> if this map contains no key-value mappings. |
| */ |
| public boolean isEmpty() { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| if (!this.composite[i].isEmpty()) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * Returns a set view of the keys contained in this map. The set is |
| * backed by the map, so changes to the map are reflected in the set, and |
| * vice-versa. If the map is modified while an iteration over the set is |
| * in progress, the results of the iteration are undefined. The set |
| * supports element removal, which removes the corresponding mapping from |
| * the map, via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, |
| * <tt>removeAll</tt> <tt>retainAll</tt>, and <tt>clear</tt> operations. |
| * It does not support the add or <tt>addAll</tt> operations. |
| * <p> |
| * This implementation returns a <code>CompositeSet</code> which |
| * composites the key sets from all of the composited maps. |
| * |
| * @return a set view of the keys contained in this map. |
| */ |
| public Set keySet() { |
| CompositeSet keys = new CompositeSet(); |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| keys.addComposited(this.composite[i].keySet()); |
| } |
| return keys; |
| } |
| |
| /** |
| * Associates the specified value with the specified key in this map |
| * (optional operation). If the map previously contained a mapping for |
| * this key, the old value is replaced by the specified value. (A map |
| * <tt>m</tt> is said to contain a mapping for a key <tt>k</tt> if and only |
| * if {@link #containsKey(Object) m.containsKey(k)} would return |
| * <tt>true</tt>.)) |
| * |
| * @param key key with which the specified value is to be associated. |
| * @param value value to be associated with the specified key. |
| * @return previous value associated with specified key, or <tt>null</tt> |
| * if there was no mapping for key. A <tt>null</tt> return can |
| * also indicate that the map previously associated <tt>null</tt> |
| * with the specified key, if the implementation supports |
| * <tt>null</tt> values. |
| * |
| * @throws UnsupportedOperationException if no MapMutator has been specified |
| * @throws ClassCastException if the class of the specified key or value |
| * prevents it from being stored in this map. |
| * @throws IllegalArgumentException if some aspect of this key or value |
| * prevents it from being stored in this map. |
| * @throws NullPointerException this map does not permit <tt>null</tt> |
| * keys or values, and the specified key or value is |
| * <tt>null</tt>. |
| */ |
| public Object put(Object key, Object value) { |
| if (this.mutator == null) { |
| throw new UnsupportedOperationException("No mutator specified"); |
| } |
| return this.mutator.put(this, this.composite, key, value); |
| } |
| |
| /** |
| * Copies all of the mappings from the specified map to this map |
| * (optional operation). The effect of this call is equivalent to that |
| * of calling {@link #put(Object,Object) put(k, v)} on this map once |
| * for each mapping from key <tt>k</tt> to value <tt>v</tt> in the |
| * specified map. The behavior of this operation is unspecified if the |
| * specified map is modified while the operation is in progress. |
| * |
| * @param map Mappings to be stored in this map. |
| * |
| * @throws UnsupportedOperationException if the <tt>putAll</tt> method is |
| * not supported by this map. |
| * |
| * @throws ClassCastException if the class of a key or value in the |
| * specified map prevents it from being stored in this map. |
| * |
| * @throws IllegalArgumentException some aspect of a key or value in the |
| * specified map prevents it from being stored in this map. |
| * @throws NullPointerException the specified map is <tt>null</tt>, or if |
| * this map does not permit <tt>null</tt> keys or values, and the |
| * specified map contains <tt>null</tt> keys or values. |
| */ |
| public void putAll(Map map) { |
| if (this.mutator == null) { |
| throw new UnsupportedOperationException("No mutator specified"); |
| } |
| this.mutator.putAll(this, this.composite, map); |
| } |
| |
| /** |
| * Removes the mapping for this key from this map if it is present |
| * (optional operation). More formally, if this map contains a mapping |
| * from key <tt>k</tt> to value <tt>v</tt> such that |
| * <code>(key==null ? k==null : key.equals(k))</code>, that mapping |
| * is removed. (The map can contain at most one such mapping.) |
| * |
| * <p>Returns the value to which the map previously associated the key, or |
| * <tt>null</tt> if the map contained no mapping for this key. (A |
| * <tt>null</tt> return can also indicate that the map previously |
| * associated <tt>null</tt> with the specified key if the implementation |
| * supports <tt>null</tt> values.) The map will not contain a mapping for |
| * the specified key once the call returns. |
| * |
| * @param key key whose mapping is to be removed from the map. |
| * @return previous value associated with specified key, or <tt>null</tt> |
| * if there was no mapping for key. |
| * |
| * @throws ClassCastException if the key is of an inappropriate type for |
| * the composited map (optional). |
| * @throws NullPointerException if the key is <tt>null</tt> and the composited map |
| * does not not permit <tt>null</tt> keys (optional). |
| * @throws UnsupportedOperationException if the <tt>remove</tt> method is |
| * not supported by the composited map containing the key |
| */ |
| public Object remove(Object key) { |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| if (this.composite[i].containsKey(key)) { |
| return this.composite[i].remove(key); |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Returns the number of key-value mappings in this map. If the |
| * map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns |
| * <tt>Integer.MAX_VALUE</tt>. |
| * |
| * @return the number of key-value mappings in this map. |
| */ |
| public int size() { |
| int size = 0; |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| size += this.composite[i].size(); |
| } |
| return size; |
| } |
| |
| /** |
| * Returns a collection view of the values contained in this map. The |
| * collection is backed by the map, so changes to the map are reflected in |
| * the collection, and vice-versa. If the map is modified while an |
| * iteration over the collection is in progress, the results of the |
| * iteration are undefined. The collection supports element removal, |
| * which removes the corresponding mapping from the map, via the |
| * <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>, |
| * <tt>removeAll</tt>, <tt>retainAll</tt> and <tt>clear</tt> operations. |
| * It does not support the add or <tt>addAll</tt> operations. |
| * |
| * @return a collection view of the values contained in this map. |
| */ |
| public Collection values() { |
| CompositeCollection keys = new CompositeCollection(); |
| for (int i = this.composite.length - 1; i >= 0; --i) { |
| keys.addComposited(this.composite[i].values()); |
| } |
| return keys; |
| } |
| |
| /** |
| * Checks if this Map equals another as per the Map specification. |
| * |
| * @param obj the object to compare to |
| * @return true if the maps are equal |
| */ |
| public boolean equals(Object obj) { |
| if (obj instanceof Map) { |
| Map map = (Map) obj; |
| return (this.entrySet().equals(map.entrySet())); |
| } |
| return false; |
| } |
| |
| /** |
| * Gets a hash code for the Map as per the Map specification. |
| */ |
| public int hashCode() { |
| int code = 0; |
| for (Iterator i = this.entrySet().iterator(); i.hasNext();) { |
| code += i.next().hashCode(); |
| } |
| return code; |
| } |
| |
| /** |
| * This interface allows definition for all of the indeterminate |
| * mutators in a CompositeMap, as well as providing a hook for |
| * callbacks on key collisions. |
| */ |
| public static interface MapMutator { |
| /** |
| * Called when adding a new Composited Map results in a |
| * key collision. |
| * |
| * @param composite the CompositeMap with the collision |
| * @param existing the Map already in the composite which contains the |
| * offending key |
| * @param added the Map being added |
| * @param intersect the intersection of the keysets of the existing and added maps |
| */ |
| public void resolveCollision( |
| CompositeMap composite, Map existing, Map added, Collection intersect); |
| |
| /** |
| * Called when the CompositeMap.put() method is invoked. |
| * |
| * @param map the CompositeMap which is being modified |
| * @param composited array of Maps in the CompositeMap being modified |
| * @param key key with which the specified value is to be associated. |
| * @param value value to be associated with the specified key. |
| * @return previous value associated with specified key, or <tt>null</tt> |
| * if there was no mapping for key. A <tt>null</tt> return can |
| * also indicate that the map previously associated <tt>null</tt> |
| * with the specified key, if the implementation supports |
| * <tt>null</tt> values. |
| * |
| * @throws UnsupportedOperationException if not defined |
| * @throws ClassCastException if the class of the specified key or value |
| * prevents it from being stored in this map. |
| * @throws IllegalArgumentException if some aspect of this key or value |
| * prevents it from being stored in this map. |
| * @throws NullPointerException this map does not permit <tt>null</tt> |
| * keys or values, and the specified key or value is |
| * <tt>null</tt>. |
| */ |
| public Object put(CompositeMap map, Map[] composited, Object key, Object value); |
| |
| /** |
| * Called when the CompositeMap.putAll() method is invoked. |
| * |
| * @param map the CompositeMap which is being modified |
| * @param composited array of Maps in the CompositeMap being modified |
| * @param mapToAdd Mappings to be stored in this CompositeMap |
| * |
| * @throws UnsupportedOperationException if not defined |
| * @throws ClassCastException if the class of the specified key or value |
| * prevents it from being stored in this map. |
| * @throws IllegalArgumentException if some aspect of this key or value |
| * prevents it from being stored in this map. |
| * @throws NullPointerException this map does not permit <tt>null</tt> |
| * keys or values, and the specified key or value is |
| * <tt>null</tt>. |
| */ |
| public void putAll(CompositeMap map, Map[] composited, Map mapToAdd); |
| } |
| } |
