/*
|
* CDDL HEADER START
|
*
|
* The contents of this file are subject to the terms of the
|
* Common Development and Distribution License, Version 1.0 only
|
* (the "License"). You may not use this file except in compliance
|
* with the License.
|
*
|
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
|
* or http://forgerock.org/license/CDDLv1.0.html.
|
* See the License for the specific language governing permissions
|
* and limitations under the License.
|
*
|
* When distributing Covered Code, include this CDDL HEADER in each
|
* file and include the License file at legal-notices/CDDLv1_0.txt.
|
* If applicable, add the following below this CDDL HEADER, with the
|
* fields enclosed by brackets "[]" replaced with your own identifying
|
* information:
|
* Portions Copyright [yyyy] [name of copyright owner]
|
*
|
* CDDL HEADER END
|
*
|
*
|
* Copyright 2009-2010 Sun Microsystems, Inc.
|
*/
|
|
package com.forgerock.opendj.util;
|
|
import java.util.Iterator;
|
|
import org.forgerock.opendj.ldap.Function;
|
|
/**
|
* Utility methods for manipulating {@link Iterable}s.
|
*/
|
public final class Iterables {
|
private static final class ArrayIterable<M> implements Iterable<M> {
|
|
private final M[] a;
|
|
// Constructed via factory methods.
|
private ArrayIterable(final M[] a) {
|
this.a = a;
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<M> iterator() {
|
return Iterators.arrayIterator(a);
|
}
|
|
}
|
|
private static final class EmptyIterable<M> implements Iterable<M> {
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<M> iterator() {
|
return Iterators.emptyIterator();
|
}
|
|
}
|
|
private static final class FilteredIterable<M, P> implements Iterable<M> {
|
|
private final Iterable<M> iterable;
|
private final P parameter;
|
private final Predicate<? super M, P> predicate;
|
|
// Constructed via factory methods.
|
private FilteredIterable(final Iterable<M> iterable,
|
final Predicate<? super M, P> predicate, final P p) {
|
this.iterable = iterable;
|
this.predicate = predicate;
|
this.parameter = p;
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<M> iterator() {
|
return Iterators.filteredIterator(iterable.iterator(), predicate, parameter);
|
}
|
|
}
|
|
private static final class SingletonIterable<M> implements Iterable<M> {
|
|
private final M value;
|
|
// Constructed via factory methods.
|
private SingletonIterable(final M value) {
|
this.value = value;
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<M> iterator() {
|
return Iterators.singletonIterator(value);
|
}
|
|
}
|
|
private static final class TransformedIterable<M, N, P> implements Iterable<N> {
|
|
private final Function<? super M, ? extends N, P> function;
|
private final Iterable<M> iterable;
|
private final P parameter;
|
|
// Constructed via factory methods.
|
private TransformedIterable(final Iterable<M> iterable,
|
final Function<? super M, ? extends N, P> function, final P p) {
|
this.iterable = iterable;
|
this.function = function;
|
this.parameter = p;
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<N> iterator() {
|
return Iterators.transformedIterator(iterable.iterator(), function, parameter);
|
}
|
|
}
|
|
private static final class UnmodifiableIterable<M> implements Iterable<M> {
|
|
private final Iterable<M> iterable;
|
|
// Constructed via factory methods.
|
private UnmodifiableIterable(final Iterable<M> iterable) {
|
this.iterable = iterable;
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
public Iterator<M> iterator() {
|
return Iterators.unmodifiableIterator(iterable.iterator());
|
}
|
|
}
|
|
private static final Iterable<Object> EMPTY_ITERABLE = new EmptyIterable<Object>();
|
|
/**
|
* Returns an iterable containing the elements of {@code a}. The returned
|
* iterable's iterator does not support element removal via the
|
* {@code remove()} method.
|
*
|
* @param <M>
|
* The type of elements contained in {@code a}.
|
* @param a
|
* The array of elements.
|
* @return An iterable containing the elements of {@code a}.
|
*/
|
public static <M> Iterable<M> arrayIterable(final M[] a) {
|
return new ArrayIterable<M>(a);
|
}
|
|
/**
|
* Returns an immutable empty iterable.
|
*
|
* @param <M>
|
* The required type of the empty iterable.
|
* @return An immutable empty iterable.
|
*/
|
@SuppressWarnings("unchecked")
|
public static <M> Iterable<M> emptyIterable() {
|
return (Iterable<M>) EMPTY_ITERABLE;
|
}
|
|
/**
|
* Returns a filtered view of {@code iterable} containing only those
|
* elements which match {@code predicate}. The returned iterable's iterator
|
* supports element removal via the {@code remove()} method subject to any
|
* constraints imposed by {@code iterable}.
|
*
|
* @param <M>
|
* The type of elements contained in {@code iterable}.
|
* @param <P>
|
* The type of the additional parameter to the predicate's
|
* {@code matches} method. Use {@link java.lang.Void} for
|
* predicates that do not need an additional parameter.
|
* @param iterable
|
* The iterable to be filtered.
|
* @param predicate
|
* The predicate.
|
* @param p
|
* A predicate specified parameter.
|
* @return A filtered view of {@code iterable} containing only those
|
* elements which match {@code predicate}.
|
*/
|
public static <M, P> Iterable<M> filteredIterable(final Iterable<M> iterable,
|
final Predicate<? super M, P> predicate, final P p) {
|
return new FilteredIterable<M, P>(iterable, predicate, p);
|
}
|
|
/**
|
* Returns a filtered view of {@code iterable} containing only those
|
* elements which match {@code predicate}. The returned iterable's iterator
|
* supports element removal via the {@code remove()} method subject to any
|
* constraints imposed by {@code iterable}.
|
*
|
* @param <M>
|
* The type of elements contained in {@code iterable}.
|
* @param iterable
|
* The iterable to be filtered.
|
* @param predicate
|
* The predicate.
|
* @return A filtered view of {@code iterable} containing only those
|
* elements which match {@code predicate}.
|
*/
|
public static <M> Iterable<M> filteredIterable(final Iterable<M> iterable,
|
final Predicate<? super M, Void> predicate) {
|
return new FilteredIterable<M, Void>(iterable, predicate, null);
|
}
|
|
/**
|
* Returns an iterable containing the single element {@code value}. The
|
* returned iterable's iterator does not support element removal via the
|
* {@code remove()} method.
|
*
|
* @param <M>
|
* The type of the single element {@code value}.
|
* @param value
|
* The single element.
|
* @return An iterable containing the single element {@code value}.
|
*/
|
public static <M> Iterable<M> singletonIterable(final M value) {
|
return new SingletonIterable<M>(value);
|
}
|
|
/**
|
* Returns a view of {@code iterable} whose values have been mapped to
|
* elements of type {@code N} using {@code function}. The returned
|
* iterable's iterator supports element removal via the {@code remove()}
|
* method subject to any constraints imposed by {@code iterable}.
|
*
|
* @param <M>
|
* The type of elements contained in {@code iterable}.
|
* @param <N>
|
* The type of elements contained in the returned iterable.
|
* @param <P>
|
* The type of the additional parameter to the function's
|
* {@code apply} method. Use {@link java.lang.Void} for functions
|
* that do not need an additional parameter.
|
* @param iterable
|
* The iterable to be transformed.
|
* @param function
|
* The function.
|
* @param p
|
* A predicate specified parameter.
|
* @return A view of {@code iterable} whose values have been mapped to
|
* elements of type {@code N} using {@code function}.
|
*/
|
public static <M, N, P> Iterable<N> transformedIterable(final Iterable<M> iterable,
|
final Function<? super M, ? extends N, P> function, final P p) {
|
return new TransformedIterable<M, N, P>(iterable, function, p);
|
}
|
|
/**
|
* Returns a view of {@code iterable} whose values have been mapped to
|
* elements of type {@code N} using {@code function}. The returned
|
* iterable's iterator supports element removal via the {@code remove()}
|
* method subject to any constraints imposed by {@code iterable}.
|
*
|
* @param <M>
|
* The type of elements contained in {@code iterable}.
|
* @param <N>
|
* The type of elements contained in the returned iterable.
|
* @param iterable
|
* The iterable to be transformed.
|
* @param function
|
* The function.
|
* @return A view of {@code iterable} whose values have been mapped to
|
* elements of type {@code N} using {@code function}.
|
*/
|
public static <M, N> Iterable<N> transformedIterable(final Iterable<M> iterable,
|
final Function<? super M, ? extends N, Void> function) {
|
return new TransformedIterable<M, N, Void>(iterable, function, null);
|
}
|
|
/**
|
* Returns a read-only view of {@code iterable} whose iterator does not
|
* support element removal via the {@code remove()}. Attempts to use the
|
* {@code remove()} method will result in a
|
* {@code UnsupportedOperationException}.
|
*
|
* @param <M>
|
* The type of elements contained in {@code iterable}.
|
* @param iterable
|
* The iterable to be made read-only.
|
* @return A read-only view of {@code iterable} whose iterator does not
|
* support element removal via the {@code remove()}.
|
*/
|
public static <M> Iterable<M> unmodifiableIterable(final Iterable<M> iterable) {
|
return new UnmodifiableIterable<M>(iterable);
|
}
|
|
// Prevent instantiation
|
private Iterables() {
|
// Do nothing.
|
}
|
|
}
|
