Commons Collections example source code file (AbstractTestBag.java)

This example Commons Collections source code file (AbstractTestBag.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

a, a, arraylist, b, b, bag, bag, c, io, ioexception, iterator, list, should, should, string, util

The Commons Collections AbstractTestBag.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.bag;

import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

import org.apache.commons.collections.AbstractTestObject;
import org.apache.commons.collections.Bag;

/**
 * Abstract test class for {@link org.apache.commons.collections.Bag Bag} methods and contracts.
 * <p>
 * To use, simply extend this class, and implement
 * the {@link #makeBag} method.
 * <p>
 * If your bag fails one of these tests by design,
 * you may still use this base set of cases.  Simply override the
 * test case (method) your bag fails.
 *
 * @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Chuck Burdick
 * @author Stephen Colebourne
 */
public abstract class AbstractTestBag extends AbstractTestObject {
//  TODO: this class should really extend from TestCollection, but the bag
//  implementations currently do not conform to the Collection interface.  Once
//  those are fixed or at least a strategy is made for resolving the issue, this
//  can be changed back to extend TestCollection instead.

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

    //-----------------------------------------------------------------------
    /**
     * Return a new, empty bag to used for testing.
     * 
     * @return the bag to be tested
     */
    public abstract Bag makeBag();

    /**
     * Implements the superclass method to return the Bag.
     * 
     * @return the bag to be tested
     */
    public Object makeObject() {
        return makeBag();
    }

    //-----------------------------------------------------------------------
    public void testBagAdd() {
        Bag bag = makeBag();
        bag.add("A");
        assertTrue("Should contain 'A'", bag.contains("A"));
        assertEquals("Should have count of 1", 1, bag.getCount("A"));
        bag.add("A");
        assertTrue("Should contain 'A'", bag.contains("A"));
        assertEquals("Should have count of 2", 2, bag.getCount("A"));
        bag.add("B");
        assertTrue(bag.contains("A"));
        assertTrue(bag.contains("B"));
    }

    public void testBagEqualsSelf() {
        Bag bag = makeBag();
        assertTrue(bag.equals(bag));
        bag.add("elt");
        assertTrue(bag.equals(bag));
        bag.add("elt"); // again
        assertTrue(bag.equals(bag));
        bag.add("elt2");
        assertTrue(bag.equals(bag));
    }

    public void testRemove() {
        Bag bag = makeBag();
        bag.add("A");
        assertEquals("Should have count of 1", 1, bag.getCount("A"));
        bag.remove("A");
        assertEquals("Should have count of 0", 0, bag.getCount("A"));
        bag.add("A");
        bag.add("A");
        bag.add("A");
        bag.add("A");
        assertEquals("Should have count of 4", 4, bag.getCount("A"));
        bag.remove("A", 0);
        assertEquals("Should have count of 4", 4, bag.getCount("A"));
        bag.remove("A", 2);
        assertEquals("Should have count of 2", 2, bag.getCount("A"));
        bag.remove("A");
        assertEquals("Should have count of 0", 0, bag.getCount("A"));
    }

    public void testRemoveAll() {
        Bag bag = makeBag();
        bag.add("A", 2);
        assertEquals("Should have count of 2", 2, bag.getCount("A"));
        bag.add("B");
        bag.add("C");
        assertEquals("Should have count of 4", 4, bag.size());
        List delete = new ArrayList();
        delete.add("A");
        delete.add("B");
        bag.removeAll(delete);
        assertEquals("Should have count of 1", 1, bag.getCount("A"));
        assertEquals("Should have count of 0", 0, bag.getCount("B"));
        assertEquals("Should have count of 1", 1, bag.getCount("C"));
        assertEquals("Should have count of 2", 2, bag.size());
    }
    
    public void testContains() {
        Bag bag = makeBag();
        
        assertEquals("Bag does not have at least 1 'A'", false, bag.contains("A"));
        assertEquals("Bag does not have at least 1 'B'", false, bag.contains("B"));
        
        bag.add("A");  // bag 1A
        assertEquals("Bag has at least 1 'A'", true, bag.contains("A"));
        assertEquals("Bag does not have at least 1 'B'", false, bag.contains("B"));
        
        bag.add("A");  // bag 2A
        assertEquals("Bag has at least 1 'A'", true, bag.contains("A"));
        assertEquals("Bag does not have at least 1 'B'", false, bag.contains("B"));
        
        bag.add("B");  // bag 2A,1B
        assertEquals("Bag has at least 1 'A'", true, bag.contains("A"));
        assertEquals("Bag has at least 1 'B'", true, bag.contains("B"));
    }

    public void testContainsAll() {
        Bag bag = makeBag();
        List known = new ArrayList();
        List known1A = new ArrayList();
        known1A.add("A");
        List known2A = new ArrayList();
        known2A.add("A");
        known2A.add("A");
        List known1B = new ArrayList();
        known1B.add("B");
        List known1A1B = new ArrayList();
        known1A1B.add("A");
        known1A1B.add("B");
        
        assertEquals("Bag containsAll of empty", true, bag.containsAll(known));
        assertEquals("Bag does not containsAll of 1 'A'", false, bag.containsAll(known1A));
        assertEquals("Bag does not containsAll of 2 'A'", false, bag.containsAll(known2A));
        assertEquals("Bag does not containsAll of 1 'B'", false, bag.containsAll(known1B));
        assertEquals("Bag does not containsAll of 1 'A' 1 'B'", false, bag.containsAll(known1A1B));
        
        bag.add("A");  // bag 1A
        assertEquals("Bag containsAll of empty", true, bag.containsAll(known));
        assertEquals("Bag containsAll of 1 'A'", true, bag.containsAll(known1A));
        assertEquals("Bag does not containsAll of 2 'A'", false, bag.containsAll(known2A));
        assertEquals("Bag does not containsAll of 1 'B'", false, bag.containsAll(known1B));
        assertEquals("Bag does not containsAll of 1 'A' 1 'B'", false, bag.containsAll(known1A1B));
        
        bag.add("A");  // bag 2A
        assertEquals("Bag containsAll of empty", true, bag.containsAll(known));
        assertEquals("Bag containsAll of 1 'A'", true, bag.containsAll(known1A));
        assertEquals("Bag containsAll of 2 'A'", true, bag.containsAll(known2A));
        assertEquals("Bag does not containsAll of 1 'B'", false, bag.containsAll(known1B));
        assertEquals("Bag does not containsAll of 1 'A' 1 'B'", false, bag.containsAll(known1A1B));
        
        bag.add("A");  // bag 3A
        assertEquals("Bag containsAll of empty", true, bag.containsAll(known));
        assertEquals("Bag containsAll of 1 'A'", true, bag.containsAll(known1A));
        assertEquals("Bag containsAll of 2 'A'", true, bag.containsAll(known2A));
        assertEquals("Bag does not containsAll of 1 'B'", false, bag.containsAll(known1B));
        assertEquals("Bag does not containsAll of 1 'A' 1 'B'", false, bag.containsAll(known1A1B));
        
        bag.add("B");  // bag 3A1B
        assertEquals("Bag containsAll of empty", true, bag.containsAll(known));
        assertEquals("Bag containsAll of 1 'A'", true, bag.containsAll(known1A));
        assertEquals("Bag containsAll of 2 'A'", true, bag.containsAll(known2A));
        assertEquals("Bag containsAll of 1 'B'", true, bag.containsAll(known1B));
        assertEquals("Bag containsAll of 1 'A' 1 'B'", true, bag.containsAll(known1A1B));
    }

    public void testSize() {
        Bag bag = makeBag();
        assertEquals("Should have 0 total items", 0, bag.size());
        bag.add("A");
        assertEquals("Should have 1 total items", 1, bag.size());
        bag.add("A");
        assertEquals("Should have 2 total items", 2, bag.size());
        bag.add("A");
        assertEquals("Should have 3 total items", 3, bag.size());
        bag.add("B");
        assertEquals("Should have 4 total items", 4, bag.size());
        bag.add("B");
        assertEquals("Should have 5 total items", 5, bag.size());
        bag.remove("A", 2);
        assertEquals("Should have 1 'A'", 1, bag.getCount("A"));
        assertEquals("Should have 3 total items", 3, bag.size());
        bag.remove("B");
        assertEquals("Should have 1 total item", 1, bag.size());
    }
    
    public void testRetainAll() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        List retains = new ArrayList();
        retains.add("B");
        retains.add("C");
        bag.retainAll(retains);
        assertEquals("Should have 2 total items", 2, bag.size());
    }

    public void testIterator() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        assertEquals("Bag should have 3 items", 3, bag.size());
        Iterator i = bag.iterator();
    
        boolean foundA = false;
        while (i.hasNext()) {
            String element = (String) i.next();
            // ignore the first A, remove the second via Iterator.remove()
            if (element.equals("A")) {
                if (foundA == false) {
                    foundA = true;
                } else {
                    i.remove();
                }
            }
        }
    
        assertTrue("Bag should still contain 'A'", bag.contains("A"));
        assertEquals("Bag should have 2 items", 2, bag.size());
        assertEquals("Bag should have 1 'A'", 1, bag.getCount("A"));
    }

    public void testIteratorFail() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        Iterator it = bag.iterator();
        it.next();
        bag.remove("A");
        try {
            it.next();
            fail("Should throw ConcurrentModificationException");
        } catch (ConcurrentModificationException e) {
            // expected
        }
    }
    
    public void testIteratorFailNoMore() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        Iterator it = bag.iterator();
        it.next();
        it.next();
        it.next();
        try {
            it.next();
            fail("Should throw NoSuchElementException");
        } catch (NoSuchElementException ex) {
            // expected
        }
    }
    
    public void testIteratorFailDoubleRemove() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        Iterator it = bag.iterator();
        it.next();
        it.next();
        assertEquals(3, bag.size());
        it.remove();
        assertEquals(2, bag.size());
        try {
            it.remove();
            fail("Should throw IllegalStateException");
        } catch (IllegalStateException ex) {
            // expected
        }
        assertEquals(2, bag.size());
        it.next();
        it.remove();
        assertEquals(1, bag.size());
    }
    
    public void testIteratorRemoveProtectsInvariants() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        assertEquals(2, bag.size());
        Iterator it = bag.iterator();
        assertEquals("A", it.next());
        assertEquals(true, it.hasNext());
        it.remove();
        assertEquals(1, bag.size());
        assertEquals(true, it.hasNext());
        assertEquals("A", it.next());
        assertEquals(false, it.hasNext());
        it.remove();
        assertEquals(0, bag.size());
        assertEquals(false, it.hasNext());
        
        Iterator it2 = bag.iterator();
        assertEquals(false, it2.hasNext());
    }
    
    public void testToArray() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        Object[] array = bag.toArray();
        int a = 0, b = 0, c = 0;
        for (int i = 0; i < array.length; i++) {
            a += (array[i].equals("A") ? 1 : 0);
            b += (array[i].equals("B") ? 1 : 0);
            c += (array[i].equals("C") ? 1 : 0);
        }
        assertEquals(2, a);
        assertEquals(2, b);
        assertEquals(1, c);
    }

    public void testToArrayPopulate() {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        String[] array = (String[]) bag.toArray(new String[0]);
        int a = 0, b = 0, c = 0;
        for (int i = 0; i < array.length; i++) {
            a += (array[i].equals("A") ? 1 : 0);
            b += (array[i].equals("B") ? 1 : 0);
            c += (array[i].equals("C") ? 1 : 0);
        }
        assertEquals(2, a);
        assertEquals(2, b);
        assertEquals(1, c);
    }

    //-----------------------------------------------------------------------
    public void testEquals() {
        Bag bag = makeBag();
        Bag bag2 = makeBag();
        assertEquals(true, bag.equals(bag2));
        bag.add("A");
        assertEquals(false, bag.equals(bag2));
        bag2.add("A");
        assertEquals(true, bag.equals(bag2));
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        bag2.add("A");
        bag2.add("B");
        bag2.add("B");
        bag2.add("C");
        assertEquals(true, bag.equals(bag2));
    }

    public void testEqualsHashBag() {
        Bag bag = makeBag();
        Bag bag2 = new HashBag();
        assertEquals(true, bag.equals(bag2));
        bag.add("A");
        assertEquals(false, bag.equals(bag2));
        bag2.add("A");
        assertEquals(true, bag.equals(bag2));
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        bag2.add("A");
        bag2.add("B");
        bag2.add("B");
        bag2.add("C");
        assertEquals(true, bag.equals(bag2));
    }

    public void testHashCode() {
        Bag bag = makeBag();
        Bag bag2 = makeBag();
        assertEquals(0, bag.hashCode());
        assertEquals(0, bag2.hashCode());
        assertEquals(bag.hashCode(), bag2.hashCode());
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        bag2.add("A");
        bag2.add("A");
        bag2.add("B");
        bag2.add("B");
        bag2.add("C");
        assertEquals(bag.hashCode(), bag2.hashCode());
        
        int total = 0;
        total += ("A".hashCode() ^ 2);
        total += ("B".hashCode() ^ 2);
        total += ("C".hashCode() ^ 1);
        assertEquals(total, bag.hashCode());
        assertEquals(total, bag2.hashCode());
    }

    //-----------------------------------------------------------------------
    public void testEmptyBagSerialization() throws IOException, ClassNotFoundException {
        Bag bag = makeBag();
        if (!(bag instanceof Serializable && isTestSerialization())) return;
        
        byte[] objekt = writeExternalFormToBytes((Serializable) bag);
        Bag bag2 = (Bag) readExternalFormFromBytes(objekt);

        assertEquals("Bag should be empty",0, bag.size());
        assertEquals("Bag should be empty",0, bag2.size());
    }

    public void testFullBagSerialization() throws IOException, ClassNotFoundException {
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        int size = bag.size();
        if (!(bag instanceof Serializable && isTestSerialization())) return;
        
        byte[] objekt = writeExternalFormToBytes((Serializable) bag);
        Bag bag2 = (Bag) readExternalFormFromBytes(objekt);

        assertEquals("Bag should be same size", size, bag.size());
        assertEquals("Bag should be same size", size, bag2.size());
    }

    /**
     * Compare the current serialized form of the Bag
     * against the canonical version in CVS.
     */
    public void testEmptyBagCompatibility() throws IOException, ClassNotFoundException {
        // test to make sure the canonical form has been preserved
        Bag bag = makeBag();
        if(bag instanceof Serializable && !skipSerializedCanonicalTests() && isTestSerialization()) {
            Bag bag2 = (Bag) readExternalFormFromDisk(getCanonicalEmptyCollectionName(bag));
            assertTrue("Bag is empty",bag2.size()  == 0);
            assertEquals(bag, bag2);
        }
    }

    /**
     * Compare the current serialized form of the Bag
     * against the canonical version in CVS.
     */
    public void testFullBagCompatibility() throws IOException, ClassNotFoundException {
        // test to make sure the canonical form has been preserved
        Bag bag = makeBag();
        bag.add("A");
        bag.add("A");
        bag.add("B");
        bag.add("B");
        bag.add("C");
        if(bag instanceof Serializable && !skipSerializedCanonicalTests() && isTestSerialization()) {
            Bag bag2 = (Bag) readExternalFormFromDisk(getCanonicalFullCollectionName(bag));
            assertEquals("Bag is the right size",bag.size(), bag2.size());
            assertEquals(bag, bag2);
        }
    }
}