Commons Collections example source code file (TestLoopingIterator.java)

This example Commons Collections source code file (TestLoopingIterator.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

arraylist, exception, exception, list, list, loopingiterator, loopingiterator, nosuchelementexception, nullpointerexception, string, string, test, testcase, testloopingiterator, util

The Commons Collections TestLoopingIterator.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.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.NoSuchElementException;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Tests the LoopingIterator class.
 * 
 * @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Jonathan Carlson
 * @author Stephen Colebourne
 */
public class TestLoopingIterator extends TestCase {

    public TestLoopingIterator(String testName) {
        super(testName);
    }

    public static Test suite() {
        return new TestSuite(TestLoopingIterator.class);
    }

    /**
     * Tests constructor exception.
     */
    public void testConstructorEx() throws Exception {
        try {
            new LoopingIterator(null);
            fail();
        } catch (NullPointerException ex) {
        }
    }
    
    /**
     * Tests whether an empty looping iterator works as designed.
     * @throws Exception  If something unexpected occurs.
     */
    public void testLooping0() throws Exception {
        List list = new ArrayList();
        LoopingIterator loop = new LoopingIterator(list);
        assertTrue("hasNext should return false", loop.hasNext() == false);

        try {
            loop.next();
            fail("NoSuchElementException was not thrown during next() call.");
        } catch (NoSuchElementException ex) {
        }
    }

    /**
     * Tests whether a populated looping iterator works as designed.
     * @throws Exception  If something unexpected occurs.
     */
    public void testLooping1() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a" }));
        LoopingIterator loop = new LoopingIterator(list);

        assertTrue("1st hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

        assertTrue("2nd hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

        assertTrue("3rd hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

    }

    /**
     * Tests whether a populated looping iterator works as designed.
     * @throws Exception  If something unexpected occurs.
     */
    public void testLooping2() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a", "b" }));
        LoopingIterator loop = new LoopingIterator(list);

        assertTrue("1st hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

        assertTrue("2nd hasNext should return true", loop.hasNext());
        assertEquals("b", loop.next());

        assertTrue("3rd hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

    }

    /**
     * Tests whether a populated looping iterator works as designed.
     * @throws Exception  If something unexpected occurs.
     */
    public void testLooping3() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a", "b", "c" }));
        LoopingIterator loop = new LoopingIterator(list);

        assertTrue("1st hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

        assertTrue("2nd hasNext should return true", loop.hasNext());
        assertEquals("b", loop.next());

        assertTrue("3rd hasNext should return true", loop.hasNext());
        assertEquals("c", loop.next());

        assertTrue("4th hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());

    }

    /**
     * Tests the remove() method on a LoopingIterator wrapped ArrayList.
     * @throws Exception  If something unexpected occurs.
     */
    public void testRemoving1() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a", "b", "c" }));
        LoopingIterator loop = new LoopingIterator(list);
        assertEquals("list should have 3 elements.", 3, list.size());

        assertTrue("1st hasNext should return true", loop.hasNext());
        assertEquals("a", loop.next());
        loop.remove();  // removes a
        assertEquals("list should have 2 elements.", 2, list.size());

        assertTrue("2nd hasNext should return true", loop.hasNext());
        assertEquals("b", loop.next());
        loop.remove();  // removes b
        assertEquals("list should have 1 elements.", 1, list.size());

        assertTrue("3rd hasNext should return true", loop.hasNext());
        assertEquals("c", loop.next());
        loop.remove();  // removes c
        assertEquals("list should have 0 elements.", 0, list.size());

        assertTrue("4th hasNext should return false", loop.hasNext() == false);
        try {
            loop.next();
            fail("Expected NoSuchElementException to be thrown.");
        } catch (NoSuchElementException ex) {
        }
    }

    /**
     * Tests the reset() method on a LoopingIterator wrapped ArrayList.
     * @throws Exception  If something unexpected occurs.
     */
    public void testReset() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a", "b", "c" }));
        LoopingIterator loop = new LoopingIterator(list);

        assertEquals("a", loop.next());
        assertEquals("b", loop.next());
        loop.reset();
        assertEquals("a", loop.next());
        loop.reset();
        assertEquals("a", loop.next());
        assertEquals("b", loop.next());
        assertEquals("c", loop.next());
        loop.reset();
        assertEquals("a", loop.next());
        assertEquals("b", loop.next());
        assertEquals("c", loop.next());
    }
    
    /**
     * Tests the size() method on a LoopingIterator wrapped ArrayList.
     * @throws Exception  If something unexpected occurs.
     */
    public void testSize() throws Exception {
        List list = new ArrayList(Arrays.asList(new String[] { "a", "b", "c" }));
        LoopingIterator loop = new LoopingIterator(list);

        assertEquals(3, loop.size());
        loop.next();
        loop.next();
        assertEquals(3, loop.size());
        loop.reset();
        assertEquals(3, loop.size());
        loop.next();
        loop.remove();
        assertEquals(2, loop.size());
    }

}