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[COLLECTIONS-263] Added MapUtils#populateMap(MultiMap, ...) methods. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1475949 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2013-04-25 20:38:58 +00:00
parent b591dacd5c
commit 766d9add03
3 changed files with 87 additions and 0 deletions
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4
src/changes/changes.xml
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@ -334,6 +334,10 @@
<action issue="COLLECTIONS-265" dev="bayard" type="update" due-to="David Saff">
"TreeBag" will now only accept "Comparable" objects as input when used with natural ordering.
</action>
<action issue="COLLECTIONS-263" dev="tn" type="add" due-to="John Hunsley">
Added methods "MapUtils#populateMap(MultiMap, ...)" to support also "MultiMap" instances
as input.
</action>
<action issue="COLLECTIONS-262" dev="bayard" type="fix" due-to="Lisen Mu">
Fixed javadoc for methods "firstKey()" and "lastKey()" in class "AbstractLinkedMap".
</action>

39
src/main/java/org/apache/commons/collections4/MapUtils.java
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@ -1704,6 +1704,45 @@ public class MapUtils {
}
}
/**
* Populates a MultiMap using the supplied <code>Transformer</code> to transform the collection
* values into keys, using the unaltered collection value as the value in the <code>MultiMap</code>.
*
* @param <K> the key type
* @param <V> the value type
* @param map the <code>MultiMap</code> to populate.
* @param collection the <code>Collection</code> to use as input values for the map.
* @param keyTransformer the <code>Transformer</code> used to transform the collection value into a key value
* @throws NullPointerException if the map, collection or transformer are null
*/
public static <K, V> void populateMap(final MultiMap<K, V> map, final Collection<? extends V> collection,
final Transformer<V, K> keyTransformer) {
populateMap(map, collection, keyTransformer, TransformerUtils.<V>nopTransformer());
}
/**
* Populates a MultiMap using the supplied <code>Transformer</code>s to transform the collection
* values into keys and values.
*
* @param <K> the key type
* @param <V> the value type
* @param <E> the type of object contained in the {@link Collection}
* @param map the <code>MultiMap</code> to populate.
* @param collection the <code>Collection</code> to use as input values for the map.
* @param keyTransformer the <code>Transformer</code> used to transform the collection value into a key value
* @param valueTransformer the <code>Transformer</code> used to transform the collection value into a value
* @throws NullPointerException if the map, collection or transformers are null
*/
public static <K, V, E> void populateMap(final MultiMap<K, V> map, final Collection<? extends E> collection,
final Transformer<E, K> keyTransformer,
final Transformer<E, V> valueTransformer) {
final Iterator<? extends E> iter = collection.iterator();
while (iter.hasNext()) {
final E temp = iter.next();
map.put(keyTransformer.transform(temp), valueTransformer.transform(temp));
}
}
/**
* Get the specified {@link Map} as an {@link IterableMap}.
*

44
src/test/java/org/apache/commons/collections4/MapUtilsTest.java
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@ -18,6 +18,7 @@ package org.apache.commons.collections4;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
@ -44,6 +45,7 @@ import org.apache.commons.collections4.keyvalue.DefaultKeyValue;
import org.apache.commons.collections4.keyvalue.DefaultMapEntry;
import org.apache.commons.collections4.map.HashedMap;
import org.apache.commons.collections4.map.LazyMap;
import org.apache.commons.collections4.map.MultiValueMap;
import org.apache.commons.collections4.map.PredicatedMap;
/**
@ -789,6 +791,48 @@ public class MapUtilsTest extends BulkTest {
}
}
/**
* Test class for populateMap(MultiMap).
*/
public static class X implements Comparable<X> {
int key;
String name;
public X(int key, String name) {
this.key = key;
this.name = name;
}
public int compareTo(X o) {
return key - o.key;
}
}
public void testPopulateMultiMap() {
// Setup Test Data
final List<X> list = new ArrayList<X>();
list.add(new X(1, "x1"));
list.add(new X(2, "x2"));
list.add(new X(2, "x3"));
list.add(new X(5, "x4"));
list.add(new X(5, "x5"));
// Now test key transform population
final MultiValueMap<Integer, X> map = MultiValueMap.multiValueMap(new TreeMap<Integer, Collection<X>>());
MapUtils.populateMap(map, list, new Transformer<X, Integer>() {
public Integer transform(X input) {
return input.key;
}
}, TransformerUtils.<X> nopTransformer());
assertEquals(list.size(), map.totalSize());
for (int i = 0; i < list.size(); i++) {
assertEquals(true, map.containsKey(list.get(i).key));
assertEquals(true, map.containsValue(list.get(i)));
}
}
public void testIterableMap() {
try {
MapUtils.iterableMap(null);