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
This commit is contained in:
Henri Yandell 2009-09-15 05:56:06 +00:00
parent 027b776f7e
commit 7701366040
1 changed files with 51 additions and 13 deletions

View File

@ -62,15 +62,13 @@ import org.apache.commons.collections.functors.FactoryTransformer;
* @author Stephen Colebourne * @author Stephen Colebourne
* @author Paul Jack * @author Paul Jack
*/ */
public class LazyMap public class LazyMap<K, V> extends AbstractMapDecorator<K, V> implements Map<K, V>, Serializable {
extends AbstractMapDecorator
implements Map, Serializable {
/** Serialization version */ /** Serialization version */
private static final long serialVersionUID = 7990956402564206740L; private static final long serialVersionUID = 7990956402564206740L;
/** The factory to use to construct elements */ /** The factory to use to construct elements */
protected final Transformer factory; protected final Transformer<? super K, ? extends V> factory;
/** /**
* Factory method to create a lazily instantiated map. * Factory method to create a lazily instantiated map.
@ -78,9 +76,11 @@ public class LazyMap
* @param map the map to decorate, must not be null * @param map the map to decorate, must not be null
* @param factory the factory to use, must not be null * @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null * @throws IllegalArgumentException if map or factory is null
* @deprecated use {@link #getLazyMap(Map, Factory)} instead.
*/ */
public static Map decorate(Map map, Factory factory) { @Deprecated
return new LazyMap(map, factory); public static <K,V> Map<K,V> decorate(Map<K,V> map, Factory<? extends V> factory) {
return getLazyMap(map, factory);
} }
/** /**
@ -90,8 +90,32 @@ public class LazyMap
* @param factory the factory to use, must not be null * @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null * @throws IllegalArgumentException if map or factory is null
*/ */
public static Map decorate(Map map, Transformer factory) { public static <K, V> LazyMap<K, V> getLazyMap(Map<K, V> map, Factory< ? extends V> factory) {
return new LazyMap(map, factory); return new LazyMap<K,V>(map, factory);
}
/**
* Factory method to create a lazily instantiated map.
*
* @param map the map to decorate, must not be null
* @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null
* @deprecated use {@link #getLazyMap(Map, Transformer)} instead.
*/
@Deprecated
public static <K,V> Map<K,V> decorate(Map<K,V> map, Transformer<? super K, ? extends V> factory) {
return getLazyMap(map, factory);
}
/**
* Factory method to create a lazily instantiated map.
*
* @param map the map to decorate, must not be null
* @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null
*/
public static <V, K> LazyMap<K, V> getLazyMap(Map<K, V> map, Transformer<? super K, ? extends V> factory) {
return new LazyMap<K,V>(map, factory);
} }
//----------------------------------------------------------------------- //-----------------------------------------------------------------------
@ -102,7 +126,7 @@ public class LazyMap
* @param factory the factory to use, must not be null * @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null * @throws IllegalArgumentException if map or factory is null
*/ */
protected LazyMap(Map map, Factory factory) { protected LazyMap(Map<K,V> map, Factory<? extends V> factory) {
super(map); super(map);
if (factory == null) { if (factory == null) {
throw new IllegalArgumentException("Factory must not be null"); throw new IllegalArgumentException("Factory must not be null");
@ -117,7 +141,7 @@ public class LazyMap
* @param factory the factory to use, must not be null * @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null * @throws IllegalArgumentException if map or factory is null
*/ */
protected LazyMap(Map map, Transformer factory) { protected LazyMap(Map<K,V> map, Transformer<? super K, ? extends V> factory) {
super(map); super(map);
if (factory == null) { if (factory == null) {
throw new IllegalArgumentException("Factory must not be null"); throw new IllegalArgumentException("Factory must not be null");
@ -146,22 +170,36 @@ public class LazyMap
* @throws ClassNotFoundException * @throws ClassNotFoundException
* @since Commons Collections 3.1 * @since Commons Collections 3.1
*/ */
@SuppressWarnings("unchecked")
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject(); in.defaultReadObject();
map = (Map) in.readObject(); map = (Map) in.readObject();
} }
//----------------------------------------------------------------------- //-----------------------------------------------------------------------
public Object get(Object key) { @Override
public V get(Object key) {
// create value for key if key is not currently in the map // create value for key if key is not currently in the map
if (map.containsKey(key) == false) { if (map.containsKey(key) == false) {
Object value = factory.transform(key); K castKey = cast(key);
map.put(key, value); V value = factory.transform(castKey);
map.put(castKey, value);
return value; return value;
} }
return map.get(key); return map.get(key);
} }
/**
* Method just to cast {@link Object}s to K where necessary. This is done to ensure that the SuppressWarnings does not
* cover other stuff that it shouldn't
* @param key .
* @return the cast key.
*/
@SuppressWarnings("unchecked")
private K cast(Object key) {
return (K) key;
}
// no need to wrap keySet, entrySet or values as they are views of // no need to wrap keySet, entrySet or values as they are views of
// existing map entries - you can't do a map-style get on them. // existing map entries - you can't do a map-style get on them.
} }