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[COLLECTIONS-361] Added CollectionUtils.filterInverse. Thanks to Jean-Noel Rouvignac for patch. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1454100 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2013-03-07 21:03:01 +00:00
parent d5d29b625f
commit 8b9a79d087
3 changed files with 47 additions and 0 deletions
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3
src/changes/changes.xml
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@ -22,6 +22,9 @@
<body>
<release version="4.0" date="TBA" description="Next release">
<action issue="COLLECTIONS-361" dev="tn" type="add" due-to="Jean-Noel Rouvignac">
Add method "CollectionUtils#filterInverse(Iterable, Predicate)".
</action>
<action issue="COLLECTIONS-372" dev="tn" type="change">
TransformingComparator now supports different types for its input/output values.
</action>

18
src/main/java/org/apache/commons/collections/CollectionUtils.java
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@ -714,6 +714,24 @@ public class CollectionUtils {
return result;
}
/**
* Filter the collection by applying a Predicate to each element. If the
* predicate returns true, remove the element.
* <p>
* This is equivalent to <pre>filter(collection, PredicateUtils.notPredicate(predicate))</pre>
* if predicate is != null.
* <p>
* If the input collection or predicate is null, there is no change made.
*
* @param <T> the type of object the {@link Iterable} contains
* @param collection the collection to get the input from, may be null
* @param predicate the predicate to use as a filter, may be null
* @return true if the collection is modified by this call, false otherwise.
*/
public static <T> boolean filterInverse(final Iterable<T> collection, final Predicate<? super T> predicate) {
return filter(collection, predicate == null ? null : PredicateUtils.notPredicate(predicate));
}
/**
* Transform the collection by applying a Transformer to each element.
* <p>

26
src/test/java/org/apache/commons/collections/CollectionUtilsTest.java
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@ -997,6 +997,32 @@ public class CollectionUtilsTest extends MockTestCase {
assertEquals(4, longs.size());
}
@Test
public void filterInverse() {
List<Integer> ints = new ArrayList<Integer>();
ints.add(1);
ints.add(2);
ints.add(3);
ints.add(3);
Iterable<Integer> iterable = ints;
assertTrue(CollectionUtils.filterInverse(iterable, EQUALS_TWO));
assertEquals(3, ints.size());
assertEquals(1, (int) ints.get(0));
assertEquals(3, (int) ints.get(1));
assertEquals(3, (int) ints.get(2));
}
@Test
public void filterInverseNullParameters() throws Exception {
List<Long> longs = Collections.nCopies(4, 10L);
assertFalse(CollectionUtils.filterInverse(longs, null));
assertEquals(4, longs.size());
assertFalse(CollectionUtils.filterInverse(null, EQUALS_TWO));
assertEquals(4, longs.size());
assertFalse(CollectionUtils.filterInverse(null, null));
assertEquals(4, longs.size());
}
@Test
public void countMatches() {
assertEquals(4, CollectionUtils.countMatches(iterableB, EQUALS_TWO));