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Generified LazyMap 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/branches/collections_jdk5_branch@571381 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Kestle 2007-08-31 05:13:56 +00:00
parent 683959a471
commit b2939e2c47
5 changed files with 133 additions and 94 deletions
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4
src/java/org/apache/commons/collections/FactoryUtils.java
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@ -64,10 +64,10 @@ public class FactoryUtils {
* This could be useful during testing as a placeholder.
*
* @see org.apache.commons.collections.functors.ConstantFactory
*
* @param <T> the "type" of null object the factory should return.
* @return the factory
*/
public static Factory nullFactory() {
public static <T> Factory<T> nullFactory() {
return ConstantFactory.NULL_INSTANCE;
}

68
src/java/org/apache/commons/collections/map/LazyMap.java
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@ -62,15 +62,15 @@ import org.apache.commons.collections.functors.FactoryTransformer;
* @author Stephen Colebourne
* @author Paul Jack
*/
public class LazyMap
extends AbstractMapDecorator
implements Map, Serializable {
public class LazyMap<K,V>
extends AbstractMapDecorator<K,V>
implements Map<K,V>, Serializable {
/** Serialization version */
private static final long serialVersionUID = 7990956402564206740L;
/** 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.
@ -78,9 +78,11 @@ public class LazyMap
* @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, Factory)} instead.
*/
public static Map decorate(Map map, Factory factory) {
return new LazyMap(map, factory);
@Deprecated
public static <K,V> Map<K,V> decorate(Map<K,V> map, Factory<? extends V> factory) {
return getLazyMap(map, factory);
}
/**
@ -90,10 +92,34 @@ public class LazyMap
* @param factory the factory to use, must not be null
* @throws IllegalArgumentException if map or factory is null
*/
public static Map decorate(Map map, Transformer factory) {
return new LazyMap(map, factory);
public static <K, V> LazyMap<K, V> getLazyMap(Map<K, V> map, Factory< ? extends V> 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);
}
//-----------------------------------------------------------------------
/**
* Constructor that wraps (not copies).
@ -102,7 +128,7 @@ public class LazyMap
* @param factory the factory to use, must not be 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);
if (factory == null) {
throw new IllegalArgumentException("Factory must not be null");
@ -117,7 +143,7 @@ public class LazyMap
* @param factory the factory to use, must not be 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);
if (factory == null) {
throw new IllegalArgumentException("Factory must not be null");
@ -146,22 +172,36 @@ public class LazyMap
* @throws ClassNotFoundException
* @since Commons Collections 3.1
*/
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
@SuppressWarnings("unchecked")
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
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
if (map.containsKey(key) == false) {
Object value = factory.transform(key);
map.put(key, value);
K castKey = cast(key);
V value = factory.transform(castKey);
map.put(castKey, value);
return value;
}
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
// existing map entries - you can't do a map-style get on them.
}

2
src/test/org/apache/commons/collections/map/AbstractTestMap.java
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@ -397,7 +397,7 @@ public abstract class AbstractTestMap extends AbstractTestObject {
*
* @return the map to be tested
*/
public abstract Map makeEmptyMap();
public abstract <K,V> Map<K,V> makeEmptyMap();
/**
* Return a new, populated map. The mappings in the map should match the

83
src/test/org/apache/commons/collections/map/TestAll.java
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@ -16,9 +16,11 @@
*/
package org.apache.commons.collections.map;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.junit.runner.RunWith;
import org.junit.runners.Suite;
import org.junit.runners.Suite.SuiteClasses;
/**
* Entry point for tests.
@ -27,51 +29,38 @@ import junit.framework.TestSuite;
* @version $Revision$ $Date$
*
* @author Stephen Colebourne
* @author Stephen Kestle
*/
@RunWith(Suite.class)
@SuiteClasses({
TestCaseInsensitiveMap.class,
TestCompositeMap.class,
TestDefaultedMap.class,
TestFlat3Map.class,
TestHashedMap.class,
TestIdentityMap.class,
TestLinkedMap.class,
TestLRUMap.class,
TestMultiKeyMap.class,
TestReferenceMap.class,
TestReferenceIdentityMap.class,
TestStaticBucketMap.class,
TestSingletonMap.class,
TestFixedSizeMap.class,
TestFixedSizeSortedMap.class,
TestLazyMap.class,
TestLazySortedMap.class,
TestListOrderedMap.class,
TestListOrderedMap2.class,
TestMultiValueMap.class,
TestPredicatedMap.class,
TestPredicatedSortedMap.class,
TestTransformedMap.class,
TestTransformedSortedMap.class,
TestUnmodifiableMap.class,
TestUnmodifiableOrderedMap.class,
TestUnmodifiableSortedMap.class
})
public class TestAll extends TestCase {
public TestAll(String testName) {
super(testName);
}
public static void main(String args[]) {
String[] testCaseName = { TestAll.class.getName() };
junit.textui.TestRunner.main(testCaseName);
}
public static Test suite() {
TestSuite suite = new TestSuite();
suite.addTest(TestCaseInsensitiveMap.suite());
suite.addTest(TestCompositeMap.suite());
suite.addTest(TestDefaultedMap.suite());
suite.addTest(TestFlat3Map.suite());
suite.addTest(TestHashedMap.suite());
suite.addTest(TestIdentityMap.suite());
suite.addTest(TestLinkedMap.suite());
suite.addTest(TestLRUMap.suite());
suite.addTest(TestMultiKeyMap.suite());
suite.addTest(TestReferenceMap.suite());
suite.addTest(TestReferenceIdentityMap.suite());
suite.addTest(TestStaticBucketMap.suite());
suite.addTest(TestSingletonMap.suite());
suite.addTest(TestFixedSizeMap.suite());
suite.addTest(TestFixedSizeSortedMap.suite());
suite.addTest(TestLazyMap.suite());
suite.addTest(TestLazySortedMap.suite());
suite.addTest(TestListOrderedMap.suite());
suite.addTest(TestListOrderedMap2.suite());
suite.addTest(TestMultiValueMap.suite());
suite.addTest(TestPredicatedMap.suite());
suite.addTest(TestPredicatedSortedMap.suite());
suite.addTest(TestTransformedMap.suite());
suite.addTest(TestTransformedSortedMap.suite());
suite.addTest(TestUnmodifiableMap.suite());
suite.addTest(TestUnmodifiableOrderedMap.suite());
suite.addTest(TestUnmodifiableSortedMap.suite());
return suite;
}
}

74
src/test/org/apache/commons/collections/map/TestLazyMap.java
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@ -16,14 +16,15 @@
*/
package org.apache.commons.collections.map;
import static org.apache.commons.collections.map.LazyMap.getLazyMap;
import java.util.HashMap;
import java.util.Map;
import junit.framework.Test;
import junit.framework.TestSuite;
import org.apache.commons.collections.Factory;
import org.apache.commons.collections.FactoryUtils;
import org.apache.commons.collections.Transformer;
import org.junit.Test;
/**
* Extension of {@link TestMap} for exercising the
@ -36,55 +37,64 @@ import org.apache.commons.collections.FactoryUtils;
*/
public class TestLazyMap extends AbstractTestMap {
protected static final Factory oneFactory = FactoryUtils.constantFactory("One");
protected static final Factory nullFactory = FactoryUtils.nullFactory();
private static final Factory<Integer> oneFactory = FactoryUtils.constantFactory(1);
private static final Factory<Object> nullFactory = FactoryUtils.nullFactory();
public TestLazyMap(String testName) {
super(testName);
}
public static Test suite() {
return new TestSuite(TestLazyMap.class);
}
public static void main(String args[]) {
String[] testCaseName = { TestLazyMap.class.getName()};
junit.textui.TestRunner.main(testCaseName);
}
//-----------------------------------------------------------------------
protected Map decorateMap(Map map, Factory factory) {
return LazyMap.decorate(map, factory);
}
public Map makeEmptyMap() {
return decorateMap(new HashMap(), nullFactory);
}
protected Map makeTestMap(Factory factory) {
return decorateMap(new HashMap(), factory);
@Override
public <K,V> Map<K,V> makeEmptyMap() {
return getLazyMap(new HashMap<K,V>(), FactoryUtils.<V>nullFactory());
}
//-----------------------------------------------------------------------
@Override
public void testMapGet() {
Map map = makeTestMap(oneFactory);
assertEquals(0, map.size());
String s1 = (String) map.get("Five");
assertEquals("One", s1);
assertEquals(1, map.size());
String s2 = (String) map.get(new String(new char[] {'F','i','v','e'}));
assertEquals("One", s2);
assertEquals(1, map.size());
assertSame(s1, s2);
//TODO eliminate need for this via superclass - see svn history.
}
map = makeTestMap(nullFactory);
@Test
public void mapGetWithFactory() {
Map<Integer, Number> map = getLazyMap(new HashMap<Integer,Number>(), oneFactory);
assertEquals(0, map.size());
Number i1 = map.get("Five");
assertEquals(1, i1);
assertEquals(1, map.size());
Number i2 = map.get(new String(new char[] {'F','i','v','e'}));
assertEquals(1, i2);
assertEquals(1, map.size());
assertSame(i1, i2);
map = getLazyMap(new HashMap<Integer,Number>(), FactoryUtils.<Long>nullFactory());
Object o = map.get("Five");
assertEquals(null,o);
assertEquals(1, map.size());
}
public String getCompatibilityVersion() {
@Test
public void mapGetWithTransformer() {
Transformer<Number, Integer> intConverter = new Transformer<Number, Integer>(){
public Integer transform(Number input) {
return input.intValue();
}
};
Map<Long, Number> map = getLazyMap(new HashMap<Long,Number>(), intConverter );
assertEquals(0, map.size());
Number i1 = map.get(123L);
assertEquals(123, i1);
assertEquals(1, map.size());
}
@Override
public String getCompatibilityVersion() {
return "3.1";
}