Merging from -r468106:814127 of collections_jdk5_branch - namely where this code was generified; mostly in r738956.
Also see the following revisions: ------------------------------------------------------------------------ r571381 | skestle | 2007-08-30 22:13:56 -0700 (Thu, 30 Aug 2007) | 1 line Generified LazyMap ------------------------------------------------------------------------ git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@815078 13f79535-47bb-0310-9956-ffa450edef68
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@ -62,15 +62,13 @@ import org.apache.commons.collections.functors.FactoryTransformer;
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* @author Stephen Colebourne
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* @author Paul Jack
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*/
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public class LazyMap
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extends AbstractMapDecorator
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implements Map, Serializable {
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public class LazyMap<K, V> extends AbstractMapDecorator<K, V> implements Map<K, V>, Serializable {
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/** Serialization version */
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private static final long serialVersionUID = 7990956402564206740L;
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/** The factory to use to construct elements */
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protected final Transformer factory;
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protected final Transformer<? super K, ? extends V> factory;
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/**
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* Factory method to create a lazily instantiated map.
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@ -78,9 +76,11 @@ public class LazyMap
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* @param map the map to decorate, must not be null
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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* @deprecated use {@link #getLazyMap(Map, Factory)} instead.
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*/
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public static Map decorate(Map map, Factory factory) {
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return new LazyMap(map, factory);
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@Deprecated
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public static <K,V> Map<K,V> decorate(Map<K,V> map, Factory<? extends V> factory) {
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return getLazyMap(map, factory);
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}
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/**
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@ -90,8 +90,32 @@ public class LazyMap
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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*/
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public static Map decorate(Map map, Transformer factory) {
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return new LazyMap(map, factory);
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public static <K, V> LazyMap<K, V> getLazyMap(Map<K, V> map, Factory< ? extends V> factory) {
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return new LazyMap<K,V>(map, factory);
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}
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/**
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* Factory method to create a lazily instantiated map.
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*
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* @param map the map to decorate, must not be null
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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* @deprecated use {@link #getLazyMap(Map, Transformer)} instead.
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*/
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@Deprecated
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public static <K,V> Map<K,V> decorate(Map<K,V> map, Transformer<? super K, ? extends V> factory) {
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return getLazyMap(map, factory);
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}
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/**
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* Factory method to create a lazily instantiated map.
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*
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* @param map the map to decorate, must not be null
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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*/
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public static <V, K> LazyMap<K, V> getLazyMap(Map<K, V> map, Transformer<? super K, ? extends V> factory) {
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return new LazyMap<K,V>(map, factory);
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}
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//-----------------------------------------------------------------------
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@ -102,7 +126,7 @@ public class LazyMap
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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*/
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protected LazyMap(Map map, Factory factory) {
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protected LazyMap(Map<K,V> map, Factory<? extends V> factory) {
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super(map);
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if (factory == null) {
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throw new IllegalArgumentException("Factory must not be null");
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@ -117,7 +141,7 @@ public class LazyMap
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* @param factory the factory to use, must not be null
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* @throws IllegalArgumentException if map or factory is null
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*/
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protected LazyMap(Map map, Transformer factory) {
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protected LazyMap(Map<K,V> map, Transformer<? super K, ? extends V> factory) {
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super(map);
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if (factory == null) {
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throw new IllegalArgumentException("Factory must not be null");
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@ -146,22 +170,36 @@ public class LazyMap
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* @throws ClassNotFoundException
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* @since Commons Collections 3.1
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*/
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@SuppressWarnings("unchecked")
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private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
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in.defaultReadObject();
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map = (Map) in.readObject();
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}
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//-----------------------------------------------------------------------
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public Object get(Object key) {
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@Override
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public V get(Object key) {
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// create value for key if key is not currently in the map
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if (map.containsKey(key) == false) {
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Object value = factory.transform(key);
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map.put(key, value);
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K castKey = cast(key);
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V value = factory.transform(castKey);
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map.put(castKey, value);
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return value;
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}
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return map.get(key);
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}
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/**
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* Method just to cast {@link Object}s to K where necessary. This is done to ensure that the SuppressWarnings does not
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* cover other stuff that it shouldn't
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* @param key .
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* @return the cast key.
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*/
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@SuppressWarnings("unchecked")
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private K cast(Object key) {
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return (K) key;
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}
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// no need to wrap keySet, entrySet or values as they are views of
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// existing map entries - you can't do a map-style get on them.
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}
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