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Move cardinality method, rename frequency to countMatches. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1683914 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart 2015-06-06 14:29:12 +00:00
parent ed1d755bab
commit 80b08f8c3a
4 changed files with 115 additions and 45 deletions
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31
src/main/java/org/apache/commons/collections4/CollectionUtils.java
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@ -614,29 +614,16 @@ public class CollectionUtils {
* @param coll the {@link Iterable} to search
* @param <O> the type of object that the {@link Iterable} may contain.
* @return the the number of occurrences of obj in coll
* @throws NullPointerException if coll is null
* @deprecated since 4.1, use {@link IterableUtils#cardinality(Iterable, Object)} instead.
* Be aware that the order of parameters has changed.
*/
@Deprecated
public static <O> int cardinality(final O obj, final Iterable<? super O> coll) {
if (coll instanceof Set<?>) {
return ((Set<? super O>) coll).contains(obj) ? 1 : 0;
if (coll == null) {
throw new NullPointerException("coll must not be null.");
}
if (coll instanceof Bag<?>) {
return ((Bag<? super O>) coll).getCount(obj);
}
int count = 0;
if (obj == null) {
for (final Object element : coll) {
if (element == null) {
count++;
}
}
} else {
for (final Object element : coll) {
if (obj.equals(element)) {
count++;
}
}
}
return count;
return IterableUtils.cardinality(coll, obj);
}
/**
@ -820,11 +807,11 @@ public class CollectionUtils {
* @param input the {@link Iterable} to get the input from, may be null
* @param predicate the predicate to use, may be null
* @return the number of matches for the predicate in the collection
* @deprecated since 4.1, use {@link IterableUtils#frequency(Iterable, Predicate)} instead
* @deprecated since 4.1, use {@link IterableUtils#countMatches(Iterable, Predicate)} instead
*/
@Deprecated
public static <C> int countMatches(final Iterable<C> input, final Predicate<? super C> predicate) {
return predicate == null ? 0 : (int) IterableUtils.frequency(input, predicate);
return predicate == null ? 0 : (int) IterableUtils.countMatches(input, predicate);
}
/**

47
src/main/java/org/apache/commons/collections4/IterableUtils.java
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@ -22,6 +22,7 @@ import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.apache.commons.collections4.functors.EqualPredicate;
import org.apache.commons.collections4.iterators.LazyIteratorChain;
@ -238,14 +239,14 @@ public class IterableUtils {
*
* @param <E> the element type
* @param iterable the iterable to filter, may be null
* @param predicate the predicate used to filter elements, must not be null
* @param predicate the predicate used to filter elements, may not be null
* @return a filtered view on the specified iterable
* @throws NullPointerException if predicate is null
*/
public static <E> Iterable<E> filteredIterable(final Iterable<E> iterable,
final Predicate<? super E> predicate) {
if (predicate == null) {
throw new NullPointerException("predicate must not be null.");
throw new NullPointerException("Predicate must not be null.");
}
return new FluentIterable<E>() {
@ -274,7 +275,7 @@ public class IterableUtils {
*/
public static <E> Iterable<E> boundedIterable(final Iterable<E> iterable, final long maxSize) {
if (maxSize < 0) {
throw new IllegalArgumentException("maxSize parameter must not be negative.");
throw new IllegalArgumentException("MaxSize parameter must not be negative.");
}
return new FluentIterable<E>() {
@ -372,7 +373,7 @@ public class IterableUtils {
*/
public static <E> Iterable<E> skippingIterable(final Iterable<E> iterable, final long elementsToSkip) {
if (elementsToSkip < 0) {
throw new IllegalArgumentException("elementsToSkip parameter must not be negative.");
throw new IllegalArgumentException("ElementsToSkip parameter must not be negative.");
}
return new FluentIterable<E>() {
@ -403,7 +404,7 @@ public class IterableUtils {
public static <I, O> Iterable<O> transformedIterable(final Iterable<I> iterable,
final Transformer<? super I, ? extends O> transformer) {
if (transformer == null) {
throw new NullPointerException("transformer must not be null.");
throw new NullPointerException("Transformer must not be null.");
}
return new FluentIterable<O>() {
@ -540,13 +541,13 @@ public class IterableUtils {
/**
* Returns an empty iterator if the argument is <code>null</code>,
* or returns {@code iterable.iterator()} otherwise.
* or {@code iterable.iterator()} otherwise.
*
* @param <E> the element type
* @param iterable the iterable, possibly <code>null</code>
* @return an empty collection if the argument is <code>null</code>
* @return an empty iterator if the argument is <code>null</code>
*/
public static <E> Iterator<E> emptyIteratorIfNull(final Iterable<E> iterable) {
private static <E> Iterator<E> emptyIteratorIfNull(final Iterable<E> iterable) {
return iterable != null ? iterable.iterator() : IteratorUtils.<E>emptyIterator();
}
@ -635,19 +636,11 @@ public class IterableUtils {
* @return the number of matches for the predicate in the collection
* @throws NullPointerException if predicate is null
*/
public static <E> long frequency(final Iterable<E> input, final Predicate<? super E> predicate) {
public static <E> long countMatches(final Iterable<E> input, final Predicate<? super E> predicate) {
if (predicate == null) {
throw new NullPointerException("Predicate must not be null.");
}
long count = 0;
if (input != null) {
for (final E o : input) {
if (predicate.evaluate(o)) {
count++;
}
}
}
return count;
return size(filteredIterable(input, predicate));
}
/**
@ -709,6 +702,24 @@ public class IterableUtils {
return matchesAny(iterable, EqualPredicate.equalPredicate(object, equator));
}
/**
* Returns the number of occurrences of the provided object in the iterable.
*
* @param <E> the type of object that the {@link Iterable} may contain
* @param iterable the {@link Iterable} to search
* @param obj the object to find the cardinality of
* @return the the number of occurrences of obj in iterable
*/
public static <E, T extends E> int cardinality(final Iterable<E> iterable, final T obj) {
if (iterable instanceof Set<?>) {
return ((Set<E>) iterable).contains(obj) ? 1 : 0;
}
if (iterable instanceof Bag<?>) {
return ((Bag<E>) iterable).getCount(obj);
}
return size(filteredIterable(iterable, EqualPredicate.<E>equalPredicate(obj)));
}
/**
* Returns the <code>index</code>-th value in the <code>iterable</code>'s {@link Iterator}, throwing
* <code>IndexOutOfBoundsException</code> if there is no such element.

3
src/test/java/org/apache/commons/collections4/CollectionUtilsTest.java
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@ -188,6 +188,7 @@ public class CollectionUtilsTest extends MockTestCase {
}
@Test
@Deprecated
public void cardinality() {
assertEquals(1, CollectionUtils.cardinality(1, iterableA));
assertEquals(2, CollectionUtils.cardinality(2, iterableA));
@ -231,6 +232,7 @@ public class CollectionUtilsTest extends MockTestCase {
}
@Test
@Deprecated
public void cardinalityOfNull() {
final List<String> list = new ArrayList<String>();
assertEquals(0, CollectionUtils.cardinality(null, list));
@ -671,6 +673,7 @@ public class CollectionUtilsTest extends MockTestCase {
}
@Test
@Deprecated
public void forAllButLastDoCollection() {
final Closure<List<? extends Number>> testClosure = ClosureUtils.invokerClosure("clear");
final Collection<List<? extends Number>> col = new ArrayList<List<? extends Number>>();

79
src/test/java/org/apache/commons/collections4/IterableUtilsTest.java
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@ -20,10 +20,13 @@ import static org.apache.commons.collections4.functors.EqualPredicate.*;
import static org.junit.Assert.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.apache.commons.collections4.bag.HashBag;
import org.junit.Assert;
@ -197,6 +200,72 @@ public class IterableUtilsTest {
} // this is what we want
}
@Test
public void cardinality() {
// null iterable test
assertEquals(0, IterableUtils.cardinality(null, 1));
assertEquals(1, IterableUtils.cardinality(iterableA, 1));
assertEquals(2, IterableUtils.cardinality(iterableA, 2));
assertEquals(3, IterableUtils.cardinality(iterableA, 3));
assertEquals(4, IterableUtils.cardinality(iterableA, 4));
assertEquals(0, IterableUtils.cardinality(iterableA, 5));
assertEquals(0, IterableUtils.cardinality(iterableB, 1L));
assertEquals(4, IterableUtils.cardinality(iterableB, 2L));
assertEquals(3, IterableUtils.cardinality(iterableB, 3L));
assertEquals(2, IterableUtils.cardinality(iterableB, 4L));
assertEquals(1, IterableUtils.cardinality(iterableB, 5L));
// Ensure that generic bounds accept valid parameters, but return
// expected results
// e.g. no longs in the "int" Iterable<Number>, and vice versa.
Iterable<Number> iterableIntAsNumber = Arrays.<Number>asList(1, 2, 3, 4, 5);
Iterable<Number> iterableLongAsNumber = Arrays.<Number>asList(1L, 2L, 3L, 4L, 5L);
assertEquals(0, IterableUtils.cardinality(iterableIntAsNumber, 2L));
assertEquals(0, IterableUtils.cardinality(iterableLongAsNumber, 2));
final Set<String> set = new HashSet<String>();
set.add("A");
set.add("C");
set.add("E");
set.add("E");
assertEquals(1, IterableUtils.cardinality(set, "A"));
assertEquals(0, IterableUtils.cardinality(set, "B"));
assertEquals(1, IterableUtils.cardinality(set, "C"));
assertEquals(0, IterableUtils.cardinality(set, "D"));
assertEquals(1, IterableUtils.cardinality(set, "E"));
final Bag<String> bag = new HashBag<String>();
bag.add("A", 3);
bag.add("C");
bag.add("E");
bag.add("E");
assertEquals(3, IterableUtils.cardinality(bag, "A"));
assertEquals(0, IterableUtils.cardinality(bag, "B"));
assertEquals(1, IterableUtils.cardinality(bag, "C"));
assertEquals(0, IterableUtils.cardinality(bag, "D"));
assertEquals(2, IterableUtils.cardinality(bag, "E"));
}
@Test
public void cardinalityOfNull() {
final List<String> list = new ArrayList<String>();
assertEquals(0, IterableUtils.cardinality(list, null));
list.add("A");
assertEquals(0, IterableUtils.cardinality(list, null));
list.add(null);
assertEquals(1, IterableUtils.cardinality(list, null));
list.add("B");
assertEquals(1, IterableUtils.cardinality(list, null));
list.add(null);
assertEquals(2, IterableUtils.cardinality(list, null));
list.add("B");
assertEquals(2, IterableUtils.cardinality(list, null));
list.add(null);
assertEquals(3, IterableUtils.cardinality(list, null));
}
@Test
public void find() {
Predicate<Number> testPredicate = equalPredicate((Number) 4);
@ -215,19 +284,19 @@ public class IterableUtilsTest {
}
@Test
public void frequency() {
assertEquals(4, IterableUtils.frequency(iterableB, EQUALS_TWO));
assertEquals(0, IterableUtils.frequency(null, EQUALS_TWO));
public void countMatches() {
assertEquals(4, IterableUtils.countMatches(iterableB, EQUALS_TWO));
assertEquals(0, IterableUtils.countMatches(null, EQUALS_TWO));
try {
assertEquals(0, IterableUtils.frequency(iterableA, null));
assertEquals(0, IterableUtils.countMatches(iterableA, null));
fail("predicate must not be null");
} catch (NullPointerException ex) {
// expected
}
try {
assertEquals(0, IterableUtils.frequency(null, null));
assertEquals(0, IterableUtils.countMatches(null, null));
fail("predicate must not be null");
} catch (NullPointerException ex) {
// expected