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Commons Collections example source code file (AbstractTestMapIterator.java)

This example Commons Collections source code file (AbstractTestMapIterator.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

abstracttestiterator, abstracttestmapiterator, illegalstateexception, illegalstateexception, iterator, key, map, map, mapiterator, mapiterator, object, object, unsupportedoperationexception, util, value

The Commons Collections AbstractTestMapIterator.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.iterators;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;

import org.apache.commons.collections.MapIterator;

/**
 * Abstract class for testing the MapIterator interface.
 * <p>
 * This class provides a framework for testing an implementation of MapIterator.
 * Concrete subclasses must provide the list iterator to be tested.
 * They must also specify certain details of how the list iterator operates by
 * overriding the supportsXxx() methods if necessary.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Stephen Colebourne
 */
public abstract class AbstractTestMapIterator extends AbstractTestIterator {

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

    //-----------------------------------------------------------------------
    /**
     * Implement this method to return a map iterator over an empty map.
     * 
     * @return an empty iterator
     */
    public abstract MapIterator makeEmptyMapIterator();

    /**
     * Implement this method to return a map iterator over a map with elements.
     * 
     * @return a full iterator
     */
    public abstract MapIterator makeFullMapIterator();

    /**
     * Implement this method to return the map which contains the same data as the
     * iterator.
     * 
     * @return a full map which can be updated
     */
    public abstract Map getMap();
    
    /**
     * Implement this method to return the confirmed map which contains the same
     * data as the iterator.
     * 
     * @return a full map which can be updated
     */
    public abstract Map getConfirmedMap();
    
    /**
     * Implements the abstract superclass method to return the list iterator.
     * 
     * @return an empty iterator
     */
    public final Iterator makeEmptyIterator() {
        return makeEmptyMapIterator();
    }

    /**
     * Implements the abstract superclass method to return the list iterator.
     * 
     * @return a full iterator
     */
    public final Iterator makeFullIterator() {
        return makeFullMapIterator();
    }

    /**
     * Whether or not we are testing an iterator that supports setValue().
     * Default is true.
     * 
     * @return true if Iterator supports set
     */
    public boolean supportsSetValue() {
        return true;
    }

    /**
     * Whether the get operation on the map structurally modifies the map,
     * such as with LRUMap. Default is false.
     * 
     * @return true if the get method structurally modifies the map
     */
    public boolean isGetStructuralModify() {
        return false;
    }
    
    /**
     * The values to be used in the add and set tests.
     * Default is two strings.
     */
    public Object[] addSetValues() {
        return new Object[] {"A", "B"};
    }

    //-----------------------------------------------------------------------
    /**
     * Test that the empty list iterator contract is correct.
     */
    public void testEmptyMapIterator() {
        if (supportsEmptyIterator() == false) {
            return;
        }

        MapIterator it = makeEmptyMapIterator();
        Map map = getMap();
        assertEquals(false, it.hasNext());
        
        // next() should throw a NoSuchElementException
        try {
            it.next();
            fail();
        } catch (NoSuchElementException ex) {}
        
        // getKey() should throw an IllegalStateException
        try {
            it.getKey();
            fail();
        } catch (IllegalStateException ex) {}
        
        // getValue() should throw an IllegalStateException
        try {
            it.getValue();
            fail();
        } catch (IllegalStateException ex) {}
        
        if (supportsSetValue() == false) {
            // setValue() should throw an UnsupportedOperationException/IllegalStateException
            try {
                it.setValue(addSetValues()[0]);
                fail();
            } catch (UnsupportedOperationException ex) {
            } catch (IllegalStateException ex) {}
        } else {
            // setValue() should throw an IllegalStateException
            try {
                it.setValue(addSetValues()[0]);
                fail();
            } catch (IllegalStateException ex) {}
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Test that the full list iterator contract is correct.
     */
    public void testFullMapIterator() {
        if (supportsFullIterator() == false) {
            return;
        }

        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        assertEquals(true, it.hasNext());
        
        assertEquals(true, it.hasNext());
        Set set = new HashSet();
        while (it.hasNext()) {
            // getKey
            Object key = it.next();
            assertSame("it.next() should equals getKey()", key, it.getKey());
            assertTrue("Key must be in map",  map.containsKey(key));
            assertTrue("Key must be unique", set.add(key));
            
            // getValue
            Object value = it.getValue();
            if (isGetStructuralModify() == false) {
                assertSame("Value must be mapped to key", map.get(key), value);
            }
            assertTrue("Value must be in map",  map.containsValue(value));

            verify();
        }
    }
    
    //-----------------------------------------------------------------------
    public void testMapIteratorSet() {
        if (supportsFullIterator() == false) {
            return;
        }

        Object newValue = addSetValues()[0];
        Object newValue2 = (addSetValues().length == 1 ? addSetValues()[0] : addSetValues()[1]);
        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        Map confirmed = getConfirmedMap();
        assertEquals(true, it.hasNext());
        Object key = it.next();
        Object value = it.getValue();
        
        if (supportsSetValue() == false) {
            try {
                it.setValue(newValue);
                fail();
            } catch (UnsupportedOperationException ex) {}
            return;
        }
        Object old = it.setValue(newValue);
        confirmed.put(key, newValue);
        assertSame("Key must not change after setValue", key, it.getKey());
        assertSame("Value must be changed after setValue", newValue, it.getValue());
        assertSame("setValue must return old value", value, old);
        assertEquals("Map must contain key", true, map.containsKey(key));
        // test against confirmed, as map may contain value twice
        assertEquals("Map must not contain old value", 
            confirmed.containsValue(old), map.containsValue(old));
        assertEquals("Map must contain new value", true, map.containsValue(newValue));
        verify();
        
        it.setValue(newValue);  // same value - should be OK
        confirmed.put(key, newValue);
        assertSame("Key must not change after setValue", key, it.getKey());
        assertSame("Value must be changed after setValue", newValue, it.getValue());
        verify();
        
        it.setValue(newValue2);  // new value
        confirmed.put(key, newValue2);
        assertSame("Key must not change after setValue", key, it.getKey());
        assertSame("Value must be changed after setValue", newValue2, it.getValue());
        verify();
    }

    //-----------------------------------------------------------------------
    public void testRemove() { // override
        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        Map confirmed = getConfirmedMap();
        assertEquals(true, it.hasNext());
        Object key = it.next();
        
        if (supportsRemove() == false) {
            try {
                it.remove();
                fail();
            } catch (UnsupportedOperationException ex) {
            }
            return;
        }
        
        it.remove();
        confirmed.remove(key);
        assertEquals(false, map.containsKey(key));
        verify();
        
        try {
            it.remove();  // second remove fails
        } catch (IllegalStateException ex) {
        }
        verify();
    }

    //-----------------------------------------------------------------------
    public void testMapIteratorSetRemoveSet() {
        if (supportsSetValue() == false || supportsRemove() == false) {
            return;
        }
        Object newValue = addSetValues()[0];
        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        Map confirmed = getConfirmedMap();
        
        assertEquals(true, it.hasNext());
        Object key = it.next();
        
        it.setValue(newValue);
        it.remove();
        confirmed.remove(key);
        verify();
        
        try {
            it.setValue(newValue);
            fail();
        } catch (IllegalStateException ex) {}
        verify();
    }

    //-----------------------------------------------------------------------
    public void testMapIteratorRemoveGetKey() {
        if (supportsRemove() == false) {
            return;
        }
        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        Map confirmed = getConfirmedMap();
        
        assertEquals(true, it.hasNext());
        Object key = it.next();
        
        it.remove();
        confirmed.remove(key);
        verify();
        
        try {
            it.getKey();
            fail();
        } catch (IllegalStateException ex) {}
        verify();
    }

    //-----------------------------------------------------------------------
    public void testMapIteratorRemoveGetValue() {
        if (supportsRemove() == false) {
            return;
        }
        MapIterator it = makeFullMapIterator();
        Map map = getMap();
        Map confirmed = getConfirmedMap();
        
        assertEquals(true, it.hasNext());
        Object key = it.next();
        
        it.remove();
        confirmed.remove(key);
        verify();
        
        try {
            it.getValue();
            fail();
        } catch (IllegalStateException ex) {}
        verify();
    }

}

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