Making ComparatorChain implement Iterable. Including test and package private copy of Collections' UnmodifiableIterator
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1167673 13f79535-47bb-0310-9956-ffa450edef68
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@ -43,7 +43,7 @@
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* @since Commons Collections 2.0
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* @since Commons Collections 2.0
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* @version $Revision$ $Date$
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* @version $Revision$ $Date$
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*/
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*/
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public class ComparatorChain<E> implements Comparator<E>, Serializable {
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public class ComparatorChain<E> implements Comparator<E>, Serializable, Iterable {
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/** The list of comparators in the chain. */
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/** The list of comparators in the chain. */
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protected List<Comparator<E>> comparatorChain = null;
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protected List<Comparator<E>> comparatorChain = null;
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@ -107,6 +107,16 @@ public int compare(E o1, E o2) {
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return 0;
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return 0;
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}
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}
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//-----------------------------------------------------------------------
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/**
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* Iterate through the chained comparators.
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*
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* @return Unmodifiable iterator over the chained comparators
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*/
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public Iterator<Comparator<E>> iterator() {
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return new UnmodifiableIterator(comparatorChain.iterator());
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}
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//-----------------------------------------------------------------------
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//-----------------------------------------------------------------------
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/**
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/**
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* Implement a hash code for this comparator that is consistent with
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* Implement a hash code for this comparator that is consistent with
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@ -0,0 +1,61 @@
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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.lang3.compare;
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import java.util.Iterator;
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/**
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* Decorates an iterator such that it cannot be modified.
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* <p>
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* Attempts to modify it will result in an UnsupportedOperationException.
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*
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* @since Commons Collections 3.0
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* @version $Revision: 1148801 $ $Date: 2011-07-20 07:44:46 -0700 (Wed, 20 Jul 2011) $
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*/
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final class UnmodifiableIterator<E> implements Iterator<E> {
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/** The iterator being decorated */
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private final Iterator<E> iterator;
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//-----------------------------------------------------------------------
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/**
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* Constructor.
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*
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* @param iterator the iterator to decorate
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*/
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public UnmodifiableIterator(Iterator<E> iterator) {
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super();
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if (iterator == null) {
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throw new IllegalArgumentException("Iterator must not be null");
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}
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this.iterator = iterator;
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}
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//-----------------------------------------------------------------------
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public boolean hasNext() {
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return iterator.hasNext();
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}
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public E next() {
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return iterator.next();
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}
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public void remove() {
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throw new UnsupportedOperationException("remove() is not supported");
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}
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}
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@ -20,6 +20,7 @@
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import static org.junit.Assert.*;
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import static org.junit.Assert.*;
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import java.util.Comparator;
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import java.util.Comparator;
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import java.util.Iterator;
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import org.junit.Before;
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import org.junit.Before;
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import org.junit.Test;
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import org.junit.Test;
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@ -51,4 +52,20 @@ public int compare(String o1, String o2) {
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assertTrue("Comparison failed", cc.compare( "ABC-123", "ABC-123" ) == 0 );
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assertTrue("Comparison failed", cc.compare( "ABC-123", "ABC-123" ) == 0 );
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}
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}
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@Test
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public void testIterate() {
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Comparator c1 = ComparableComparator.INSTANCE;
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Comparator c2 = new ComparableComparator();
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Comparator c3 = new NullComparator();
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Comparator c4 = new ReverseComparator();
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Iterable cc = new ComparatorChain(c1, c2, c3, c4);
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Iterator itr = cc.iterator();
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assertEquals( "Iteration failed", c1, itr.next() );
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assertEquals( "Iteration failed", c2, itr.next() );
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assertEquals( "Iteration failed", c3, itr.next() );
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assertEquals( "Iteration failed", c4, itr.next() );
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assertFalse( "Iteration failed", itr.hasNext() );
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}
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}
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}
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