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Posted to commits@commons.apache.org by tn...@apache.org on 2013/05/12 18:56:26 UTC
svn commit: r1481605 -
/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java
Author: tn
Date: Sun May 12 16:56:26 2013
New Revision: 1481605
URL: http://svn.apache.org/r1481605
Log:
[COLLECTIONS-466] Replace Collection with Iterable where applicable in CollectionUtils.
Modified:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java
Modified: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java
URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java?rev=1481605&r1=1481604&r2=1481605&view=diff
==============================================================================
--- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java (original)
+++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/CollectionUtils.java Sun May 12 16:56:26 2013
@@ -43,7 +43,8 @@ import org.apache.commons.collections4.i
/**
* Provides utility methods and decorators for {@link Collection} instances.
- * Method parameters will take {@link Iterable} objects when possible.
+ * <p>
+ * NOTE: From 4.0, method parameters will take {@link Iterable} objects when possible.
*
* @since 1.0
* @version $Id$
@@ -212,11 +213,11 @@ public class CollectionUtils {
/**
* Returns a {@link Collection} containing the union of the given
- * {@link Collection}s.
+ * {@link Iterable}s.
* <p>
* The cardinality of each element in the returned {@link Collection} will
* be equal to the maximum of the cardinality of that element in the two
- * given {@link Collection}s.
+ * given {@link Iterable}s.
*
* @param a the first collection, must not be null
* @param b the second collection, must not be null
@@ -235,11 +236,11 @@ public class CollectionUtils {
/**
* Returns a {@link Collection} containing the intersection of the given
- * {@link Collection}s.
+ * {@link Iterable}s.
* <p>
* The cardinality of each element in the returned {@link Collection} will
* be equal to the minimum of the cardinality of that element in the two
- * given {@link Collection}s.
+ * given {@link Iterable}s.
*
* @param a the first collection, must not be null
* @param b the second collection, must not be null
@@ -259,7 +260,7 @@ public class CollectionUtils {
/**
* Returns a {@link Collection} containing the exclusive disjunction
- * (symmetric difference) of the given {@link Collection}s.
+ * (symmetric difference) of the given {@link Iterable}s.
* <p>
* The cardinality of each element <i>e</i> in the returned
* {@link Collection} will be equal to
@@ -432,12 +433,8 @@ public class CollectionUtils {
* Only those elements present in the collection will appear as
* keys in the map.
*
- * @param coll
- * the collection to get the cardinality map for, must not be
- * null
- * @param <O>
- * the type of object in the returned {@link Map}. This is a
- * super type of <I>.
+ * @param <O> the type of object in the returned {@link Map}. This is a super type of <I>.
+ * @param coll the collection to get the cardinality map for, must not be null
* @return the populated cardinality map
*/
public static <O> Map<O, Integer> getCardinalityMap(final Iterable<? extends O> coll) {
@@ -638,12 +635,12 @@ public class CollectionUtils {
* If the input collection or predicate is null, or no element of the collection
* matches the predicate, null is returned.
*
- * @param <T> the type of object the {@link Collection} contains
+ * @param <T> the type of object the {@link Iterable} contains
* @param collection the collection to search, may be null
* @param predicate the predicate to use, may be null
* @return the first element of the collection which matches the predicate or null if none could be found
*/
- public static <T> T find(final Collection<T> collection, final Predicate<? super T> predicate) {
+ public static <T> T find(final Iterable<T> collection, final Predicate<? super T> predicate) {
if (collection != null && predicate != null) {
for (final T item : collection) {
if (predicate.evaluate(item)) {
@@ -659,13 +656,13 @@ public class CollectionUtils {
* <p>
* If the input collection or closure is null, there is no change made.
*
- * @param <T> the type of object the {@link Collection} contains
+ * @param <T> the type of object the {@link Iterable} contains
* @param <C> the closure type
* @param collection the collection to get the input from, may be null
* @param closure the closure to perform, may be null
* @return closure
*/
- public static <T, C extends Closure<? super T>> C forAllDo(final Collection<T> collection, final C closure) {
+ public static <T, C extends Closure<? super T>> C forAllDo(final Iterable<T> collection, final C closure) {
if (collection != null && closure != null) {
for (final T element : collection) {
closure.execute(element);
@@ -700,14 +697,14 @@ public class CollectionUtils {
* <p>
* If the input collection or closure is null, there is no change made.
*
- * @param <T> the type of object the {@link Collection} contains
+ * @param <T> the type of object the {@link Iterable} contains
* @param <C> the closure type
* @param collection the collection to get the input from, may be null
* @param closure the closure to perform, may be null
* @return the last element in the collection, or null if either collection or closure is null
* @since 4.0
*/
- public static <T, C extends Closure<? super T>> T forAllButLastDo(final Collection<T> collection,
+ public static <T, C extends Closure<? super T>> T forAllButLastDo(final Iterable<T> collection,
final C closure) {
return collection != null && closure != null ? forAllButLastDo(collection.iterator(), closure) : null;
}
@@ -794,7 +791,7 @@ public class CollectionUtils {
* may reduce in size due to calling this method.
*
* @param <C> the type of object the {@link Collection} contains
- * @param collection the {@link Iterable} to get the input from, may be null
+ * @param collection the {@link Collection} to get the input from, may be null
* @param transformer the transformer to perform, may be null
*/
public static <C> void transform(final Collection<C> collection,
@@ -865,15 +862,17 @@ public class CollectionUtils {
* <p>
* A <code>null</code> predicate matches no elements.
*
- * @param <O> the type of object the {@link Collection} contains
+ * @param <O> the type of object the {@link Iterable} contains
* @param inputCollection the collection to get the input from, may not be null
* @param predicate the predicate to use, may be null
* @return the elements matching the predicate (new list)
* @throws NullPointerException if the input collection is null
*/
- public static <O> Collection<O> select(final Collection<? extends O> inputCollection,
+ public static <O> Collection<O> select(final Iterable<? extends O> inputCollection,
final Predicate<? super O> predicate) {
- return select(inputCollection, predicate, new ArrayList<O>(inputCollection.size()));
+ final Collection<O> answer = inputCollection instanceof Collection<?> ?
+ new ArrayList<O>(((Collection<?>) inputCollection).size()) : new ArrayList<O>();
+ return select(inputCollection, predicate, answer);
}
/**
@@ -883,7 +882,7 @@ public class CollectionUtils {
* If the input collection or predicate is null, there is no change to the
* output collection.
*
- * @param <O> the type of object the {@link Collection} contains
+ * @param <O> the type of object the {@link Iterable} contains
* @param <R> the type of the output {@link Collection}
* @param inputCollection the collection to get the input from, may be null
* @param predicate the predicate to use, may be null
@@ -891,7 +890,7 @@ public class CollectionUtils {
* and predicate or not null
* @return the outputCollection
*/
- public static <O, R extends Collection<? super O>> R select(final Collection<? extends O> inputCollection,
+ public static <O, R extends Collection<? super O>> R select(final Iterable<? extends O> inputCollection,
final Predicate<? super O> predicate, final R outputCollection) {
if (inputCollection != null && predicate != null) {
@@ -911,15 +910,17 @@ public class CollectionUtils {
* If the input predicate is <code>null</code>, the result is an empty
* list.
*
- * @param <O> the type of object the {@link Collection} contains
+ * @param <O> the type of object the {@link Iterable} contains
* @param inputCollection the collection to get the input from, may not be null
* @param predicate the predicate to use, may be null
* @return the elements <b>not</b> matching the predicate (new list)
* @throws NullPointerException if the input collection is null
*/
- public static <O> Collection<O> selectRejected(final Collection<? extends O> inputCollection,
+ public static <O> Collection<O> selectRejected(final Iterable<? extends O> inputCollection,
final Predicate<? super O> predicate) {
- return selectRejected(inputCollection, predicate, new ArrayList<O>(inputCollection.size()));
+ final Collection<O> answer = inputCollection instanceof Collection<?> ?
+ new ArrayList<O>(((Collection<?>) inputCollection).size()) : new ArrayList<O>();
+ return selectRejected(inputCollection, predicate, answer);
}
/**
@@ -929,7 +930,7 @@ public class CollectionUtils {
* If the input predicate is <code>null</code>, no elements are added to
* <code>outputCollection</code>.
*
- * @param <O> the type of object the {@link Collection} contains
+ * @param <O> the type of object the {@link Iterable} contains
* @param <R> the type of the output {@link Collection}
* @param inputCollection the collection to get the input from, may be null
* @param predicate the predicate to use, may be null
@@ -937,7 +938,7 @@ public class CollectionUtils {
* and predicate or not null
* @return outputCollection
*/
- public static <O, R extends Collection<? super O>> R selectRejected(final Collection<? extends O> inputCollection,
+ public static <O, R extends Collection<? super O>> R selectRejected(final Iterable<? extends O> inputCollection,
final Predicate<? super O> predicate, final R outputCollection) {
if (inputCollection != null && predicate != null) {
@@ -956,18 +957,18 @@ public class CollectionUtils {
* <p>
* If the input transformer is null, the result is an empty list.
*
- * @param inputCollection the collection to get the input from, may not be null
- * @param transformer the transformer to use, may be null
* @param <I> the type of object in the input collection
* @param <O> the type of object in the output collection
+ * @param inputCollection the collection to get the input from, may not be null
+ * @param transformer the transformer to use, may be null
* @return the transformed result (new list)
* @throws NullPointerException if the input collection is null
*/
public static <I, O> Collection<O> collect(final Iterable<I> inputCollection,
final Transformer<? super I, ? extends O> transformer) {
- final ArrayList<O> answer = new ArrayList<O>();
- collect(inputCollection, transformer, answer);
- return answer;
+ final Collection<O> answer = inputCollection instanceof Collection<?> ?
+ new ArrayList<O>(((Collection<?>) inputCollection).size()) : new ArrayList<O>();
+ return collect(inputCollection, transformer, answer);
}
/**
@@ -985,9 +986,7 @@ public class CollectionUtils {
*/
public static <I, O> Collection<O> collect(final Iterator<I> inputIterator,
final Transformer<? super I, ? extends O> transformer) {
- final ArrayList<O> answer = new ArrayList<O>();
- collect(inputIterator, transformer, answer);
- return answer;
+ return collect(inputIterator, transformer, new ArrayList<O>());
}
/**
@@ -997,13 +996,13 @@ public class CollectionUtils {
* If the input collection or transformer is null, there is no change to the
* output collection.
*
+ * @param <I> the type of object in the input collection
+ * @param <O> the type of object in the output collection
+ * @param <R> the output type of the transformer - this extends O.
* @param inputCollection the collection to get the input from, may be null
* @param transformer the transformer to use, may be null
* @param outputCollection the collection to output into, may not be null if the inputCollection
* and transformer are not null
- * @param <I> the type of object in the input collection
- * @param <O> the type of object in the output collection
- * @param <R> the output type of the transformer - this extends O.
* @return the outputCollection with the transformed input added
* @throws NullPointerException if the output collection is null and both, inputCollection and
* transformer are not null
@@ -1499,8 +1498,8 @@ public class CollectionUtils {
* @throws IllegalArgumentException if either collection is null
* @since 4.0
*/
- public static <O extends Comparable<? super O>> List<O> collate(Collection<? extends O> a,
- Collection<? extends O> b) {
+ public static <O extends Comparable<? super O>> List<O> collate(Iterable<? extends O> a,
+ Iterable<? extends O> b) {
return collate(a, b, ComparatorUtils.<O>naturalComparator(), true);
}
@@ -1520,8 +1519,8 @@ public class CollectionUtils {
* @throws IllegalArgumentException if either collection is null
* @since 4.0
*/
- public static <O extends Comparable<? super O>> List<O> collate(final Collection<? extends O> a,
- final Collection<? extends O> b,
+ public static <O extends Comparable<? super O>> List<O> collate(final Iterable<? extends O> a,
+ final Iterable<? extends O> b,
final boolean includeDuplicates) {
return collate(a, b, ComparatorUtils.<O>naturalComparator(), includeDuplicates);
}
@@ -1540,7 +1539,7 @@ public class CollectionUtils {
* @throws IllegalArgumentException if either collection or the comparator is null
* @since 4.0
*/
- public static <O> List<O> collate(final Collection<? extends O> a, final Collection<? extends O> b,
+ public static <O> List<O> collate(final Iterable<? extends O> a, final Iterable<? extends O> b,
final Comparator<? super O> c) {
return collate(a, b, c, true);
}
@@ -1561,7 +1560,7 @@ public class CollectionUtils {
* @throws IllegalArgumentException if either collection or the comparator is null
* @since 4.0
*/
- public static <O> List<O> collate(final Collection<? extends O> a, final Collection<? extends O> b,
+ public static <O> List<O> collate(final Iterable<? extends O> a, final Iterable<? extends O> b,
final Comparator<? super O> c, final boolean includeDuplicates) {
if (a == null || b == null) {
@@ -1571,7 +1570,10 @@ public class CollectionUtils {
throw new IllegalArgumentException("The comparator must not be null");
}
- final int totalSize = Math.max(1, a.size() + b.size());
+ // if both Iterables are a Collection, we can estimate the size
+ final int totalSize = a instanceof Collection<?> && b instanceof Collection<?> ?
+ Math.max(1, ((Collection<?>) a).size() + ((Collection<?>) b).size()) : 10;
+
final Iterator<O> iterator = new CollatingIterator<O>(c, a.iterator(), b.iterator());
if (includeDuplicates) {
return IteratorUtils.toList(iterator, totalSize);