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Commons Collections example source code file (AbstractTestMapEntry.java)

This example Commons Collections source code file (AbstractTestMapEntry.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Collections tags/keywords

abstracttestmapentry, abstracttestmapentry, hashmap, illegalargumentexception, illegalargumentexception, map, object, object, should, string, string, testcase, util

The Commons Collections AbstractTestMapEntry.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.keyvalue;

import java.util.HashMap;
import java.util.Map;

import junit.framework.TestCase;

/**
 * Abstract tests that can be extended to test any Map.Entry implementation.
 * Subclasses must implement {@link #makeMapEntry(Object, Object)} to return
 * a new Map.Entry of the type being tested. Subclasses must also implement
 * {@link #testConstructors()} to test the constructors of the Map.Entry
 * type being tested.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Neil O'Toole
 */
public abstract class AbstractTestMapEntry extends TestCase {
    
    protected final String key = "name";
    protected final String value = "duke";

    /**
     * JUnit constructor.
     * 
     * @param testName  the test name
     */
    public AbstractTestMapEntry(String testName) {
        super(testName);
    }

    //-----------------------------------------------------------------------
    /**
     * Make an instance of Map.Entry with the default (null) key and value.
     * This implementation simply calls {@link #makeMapEntry(Object, Object)}
     * with null for key and value. Subclasses can override this method if desired.
     */
    public Map.Entry makeMapEntry() {
        return makeMapEntry(null, null);
    }

    /**
     * Make an instance of Map.Entry with the specified key and value.
     * Subclasses should override this method to return a Map.Entry
     * of the type being tested.
     */
    public abstract Map.Entry makeMapEntry(Object key, Object value);

    /**
     * Makes a Map.Entry of a type that's known to work correctly.
     */
    public Map.Entry makeKnownMapEntry() {
        return makeKnownMapEntry(null, null);
    }

    /**
     * Makes a Map.Entry of a type that's known to work correctly.
     */
    public Map.Entry makeKnownMapEntry(Object key, Object value) {
        Map map = new HashMap(1);
        map.put(key, value);
        Map.Entry entry = (Map.Entry) map.entrySet().iterator().next();
        return entry;
    }

    //-----------------------------------------------------------------------
    public void testAccessorsAndMutators() {
        Map.Entry entry = makeMapEntry(key, value);

        assertTrue(entry.getKey() == key);

        entry.setValue(value);
        assertTrue(entry.getValue() == value);

        // check that null doesn't do anything funny
        entry = makeMapEntry(null, null);
        assertTrue(entry.getKey() == null);

        entry.setValue(null);
        assertTrue(entry.getValue() == null);
    }

    /**
     * Subclasses should override this method to test the
     * desired behaviour of the class with respect to
     * handling of self-references.
     *
     */

    public void testSelfReferenceHandling() {
        // test that #setValue does not permit
        //  the MapEntry to contain itself (and thus cause infinite recursion
        //  in #hashCode and #toString)

        Map.Entry entry = makeMapEntry();

        try {
            entry.setValue(entry);
            fail("Should throw an IllegalArgumentException");
        } catch (IllegalArgumentException iae) {
            // expected to happen...

            // check that the KVP's state has not changed
            assertTrue(entry.getKey() == null && entry.getValue() == null);
        }
    }

    /**
     * Subclasses should provide tests for their constructors.
     *
     */
    public abstract void testConstructors();

    public void testEqualsAndHashCode() {
        // 1. test with object data
        Map.Entry e1 = makeMapEntry(key, value);
        Map.Entry e2 = makeKnownMapEntry(key, value);

        assertTrue(e1.equals(e1));
        assertTrue(e2.equals(e1));
        assertTrue(e1.equals(e2));
        assertTrue(e1.hashCode() == e2.hashCode());

        // 2. test with nulls
        e1 = makeMapEntry();
        e2 = makeKnownMapEntry();

        assertTrue(e1.equals(e1));
        assertTrue(e2.equals(e1));
        assertTrue(e1.equals(e2));
        assertTrue(e1.hashCode() == e2.hashCode());
    }

    public void testToString() {
        Map.Entry entry = makeMapEntry(key, value);
        assertTrue(entry.toString().equals(entry.getKey() + "=" + entry.getValue()));

        // test with nulls
        entry = makeMapEntry();
        assertTrue(entry.toString().equals(entry.getKey() + "=" + entry.getValue()));
    }

}

Other Commons Collections examples (source code examples)

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