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Applying Dave Meikle's patch to COLLECTIONS-194 - adding a populateMap method to MapUtils 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@657293 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Henri Yandell 2008-05-17 05:29:40 +00:00
parent e6d4f46544
commit 015f5a8724
2 changed files with 71 additions and 0 deletions
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33
src/java/org/apache/commons/collections/MapUtils.java
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@ -28,6 +28,7 @@ import java.util.Properties;
import java.util.ResourceBundle;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.Collection;
import org.apache.commons.collections.map.FixedSizeMap;
import org.apache.commons.collections.map.FixedSizeSortedMap;
@ -1642,4 +1643,36 @@ public class MapUtils {
return LazySortedMap.decorate(map, transformerFactory);
}
/**
* <p>
* Populates a Map using the supplied <code>Transformer</code> to transform the collection
* values into keys, using the unaltered collection value as the value in the <code>Map</code>.
* </p>
* @param map the <code>Map</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 void populateMap(Map map, Collection collection, Transformer keyTransformer) {
populateMap(map, collection, keyTransformer, TransformerUtils.nopTransformer());
}
/**
* <p>
* Populates a Map using the supplied <code>Transformer</code>s to transform the collection
* values into keys and values.
* </p>
* @param map the <code>Map</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 void populateMap(Map map, Collection collection, Transformer keyTransformer, Transformer valueTransformer) {
Iterator iter = collection.iterator();
while (iter.hasNext()) {
Object temp = iter.next();
map.put(keyTransformer.transform(temp), valueTransformer.transform(temp));
}
}
}

38
src/test/org/apache/commons/collections/TestMapUtils.java
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@ -26,6 +26,8 @@ import java.util.Map;
import java.util.ResourceBundle;
import java.util.Set;
import java.util.TreeMap;
import java.util.List;
import java.util.ArrayList;
import junit.framework.Test;
@ -34,6 +36,7 @@ import org.apache.commons.collections.keyvalue.DefaultMapEntry;
import org.apache.commons.collections.map.LazyMap;
import org.apache.commons.collections.map.PredicatedMap;
import org.apache.commons.collections.map.TestPredicatedMap;
import org.apache.commons.collections.collection.TestTransformedCollection;
/**
* Tests for MapUtils.
@ -805,4 +808,39 @@ public class TestMapUtils extends BulkTest {
assertEquals(false, MapUtils.isNotEmpty(map));
}
public void testPopulateMap() {
// Setup Test Data
List list = new ArrayList();
list.add("1");
list.add("3");
list.add("5");
list.add("7");
list.add("2");
list.add("4");
list.add("6");
// Now test key transform population
Map map = new HashMap();
MapUtils.populateMap(map, list, TestTransformedCollection.STRING_TO_INTEGER_TRANSFORMER);
assertEquals(list.size(), map.size());
for (int i = 0; i < list.size(); i++) {
assertEquals(true, map.containsKey(new Integer((String) list.get(i))));
assertEquals(false, map.containsKey(list.get(i)));
assertEquals(true, map.containsValue(list.get(i)));
assertEquals(list.get(i), map.get(new Integer((String) list.get(i))));
}
// Now test both Key-Value transform population
map = new HashMap();
MapUtils.populateMap(map, list, TestTransformedCollection.STRING_TO_INTEGER_TRANSFORMER, TestTransformedCollection.STRING_TO_INTEGER_TRANSFORMER);
assertEquals(list.size(), map.size());
for (int i = 0; i < list.size(); i++) {
assertEquals(true, map.containsKey(new Integer((String) list.get(i))));
assertEquals(false, map.containsKey(list.get(i)));
assertEquals(true, map.containsValue(new Integer((String) list.get(i))));
assertEquals(new Integer((String) list.get(i)), map.get(new Integer((String) list.get(i))));
}
}
}