user/test/org/apache/commons/collections/TestComparator.java

/*
 * Copyright 1999-2004 The Apache Software Foundation
 *
 * Licensed 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;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;


public abstract class TestComparator extends TestObject {
 

    public abstract Comparator makeComparator();
    public abstract List getComparableObjectsOrdered();

    public Object makeObject() {
        return makeComparator();
    }

    /**
     * There were no Comparators in version 1.x.
     * 
     * @return 2
     */
    public int getCompatibilityVersion() {
        return 2;
    }

    public void reverseObjects(List list) {
        Collections.reverse(list);
    }

     

    /**
     * Sort object according to the given Comparator.
     * 
     * @param list       List to sort
     * @param comparator sorting comparator
     */
    public void sortObjects(List list, Comparator comparator) {

        Collections.sort(list,comparator);

    }

    public boolean supportsEmptyCollections() {
        return false;
    }

    public boolean supportsFullCollections() {
        return false;
    }

    public void testEmptyListSort() {
        List list = new ArrayList();
        sortObjects(list,makeComparator());

        List list2 = new ArrayList();
        
        assertTrue("Comparator cannot sort empty lists",
                   list2.equals(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));

    }

     
    

    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() {
        Comparator comparator = null;

        
        // 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:" + randomList,
                   orderedList.equals(randomList));
    }

}