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Commons Collections example source code file (AbstractTestComparator.java)
The Commons Collections AbstractTestComparator.java source code/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.collections.comparators; import java.io.FileNotFoundException; import java.io.IOException; import java.io.Serializable; import java.util.Collections; import java.util.Comparator; import java.util.LinkedList; import java.util.List; import org.apache.commons.collections.AbstractTestObject; /** * Abstract test class for testing the Comparator interface. * <p> * Concrete subclasses declare the comparator to be tested. * They also declare certain aspects of the tests. * * @author Stephen Colebourne */ public abstract class AbstractTestComparator extends AbstractTestObject { /** * JUnit constructor. * * @param testName the test class name */ public AbstractTestComparator(String testName) { super(testName); } //----------------------------------------------------------------------- /** * Implement this method to return the comparator to test. * * @return the comparator to test */ public abstract Comparator makeComparator(); /** * Implement this method to return a list of sorted objects. * * @return sorted objects */ public abstract List getComparableObjectsOrdered(); //----------------------------------------------------------------------- /** * Implements the abstract superclass method to return the comparator. * * @return a full iterator */ public Object makeObject() { return makeComparator(); } /** * Overrides superclass to block tests. */ public boolean supportsEmptyCollections() { return false; } /** * Overrides superclass to block tests. */ public boolean supportsFullCollections() { return false; } /** * Overrides superclass to set the compatability to version 2 * as there were no Comparators in version 1.x. */ public String getCompatibilityVersion() { return "2"; } //----------------------------------------------------------------------- /** * Reverse the list. */ protected void reverseObjects(List list) { Collections.reverse(list); } /** * Randomize the list. */ protected void randomizeObjects(List list) { Collections.shuffle(list); } /** * Sort the list. */ protected void sortObjects(List list, Comparator comparator) { Collections.sort(list,comparator); } //----------------------------------------------------------------------- /** * Test sorting an empty list */ public void testEmptyListSort() { List list = new LinkedList(); sortObjects(list, makeComparator()); List list2 = new LinkedList(); assertTrue("Comparator cannot sort empty lists", list2.equals(list)); } /** * Test sorting a reversed list. */ public void testReverseListSort() { Comparator comparator = makeComparator(); List randomList = getComparableObjectsOrdered(); reverseObjects(randomList); sortObjects(randomList,comparator); List orderedList = getComparableObjectsOrdered(); assertTrue("Comparator did not reorder the List correctly", orderedList.equals(randomList)); } /** * Test sorting a random list. */ public void testRandomListSort() { Comparator comparator = makeComparator(); List randomList = getComparableObjectsOrdered(); randomizeObjects(randomList); sortObjects(randomList,comparator); List orderedList = getComparableObjectsOrdered(); /* debug Iterator i = randomList.iterator(); while (i.hasNext()) { System.out.println(i.next()); } */ assertTrue("Comparator did not reorder the List correctly", orderedList.equals(randomList)); } /** * Nearly all Comparators should be Serializable. */ public void testComparatorIsSerializable() { Comparator comparator = makeComparator(); assertTrue("This comparator should be Serializable.", comparator instanceof Serializable); } public String getCanonicalComparatorName(Object object) { StringBuffer retval = new StringBuffer(); retval.append("data/test/"); String colName = object.getClass().getName(); colName = colName.substring(colName.lastIndexOf(".")+1,colName.length()); retval.append(colName); retval.append(".version"); retval.append(getCompatibilityVersion()); retval.append(".obj"); return retval.toString(); } /** * Compare the current serialized form of the Comparator * against the canonical version in CVS. */ public void testComparatorCompatibility() throws IOException, ClassNotFoundException { if(!skipSerializedCanonicalTests()) { Comparator comparator = null; // test to make sure the canonical form has been preserved try { comparator = (Comparator) readExternalFormFromDisk(getCanonicalComparatorName(makeComparator())); } catch (FileNotFoundException exception) { boolean autoCreateSerialized = false; if(autoCreateSerialized) { comparator = makeComparator(); String fileName = getCanonicalComparatorName(comparator); writeExternalFormToDisk((Serializable) comparator, fileName); fail("Serialized form could not be found. A serialized version " + "has now been written (and should be added to CVS): " + fileName); } else { fail("The Serialized form could be located to test serialization " + "compatibility: " + exception.getMessage()); } } // make sure the canonical form produces the ordering we currently // expect List randomList = getComparableObjectsOrdered(); reverseObjects(randomList); sortObjects(randomList,comparator); List orderedList = getComparableObjectsOrdered(); assertTrue("Comparator did not reorder the List correctly", orderedList.equals(randomList)); } } } Other Commons Collections examples (source code examples)Here is a short list of links related to this Commons Collections AbstractTestComparator.java source code file: |
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