PeekableIteratorTests.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.test.utility.iterators;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;

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

import org.eclipse.persistence.tools.workbench.utility.iterators.PeekableIterator;

public class PeekableIteratorTests extends TestCase {

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

    public PeekableIteratorTests(String name) {
        super(name);
    }

    public void testUnsupportedOperationException() {
        boolean exCaught = false;
        for (Iterator stream = this.buildPeekableIterator(); stream.hasNext(); ) {
            String string = (String) stream.next();
            if (string.equals("three")) {
                try {
                    stream.remove();
                } catch (UnsupportedOperationException ex) {
                    exCaught = true;
                }
            }
        }
        assertTrue("UnsupportedOperationException not thrown", exCaught);
    }

    public void testNoSuchElementException() {
        boolean exCaught = false;
        Iterator stream = this.buildPeekableIterator();
        String string = null;
        while (stream.hasNext()) {
            string = (String) stream.next();
        }
        try {
            string = (String) stream.next();
        } catch (NoSuchElementException ex) {
            exCaught = true;
        }
        assertTrue("NoSuchElementException not thrown: " + string, exCaught);
    }

    public void testHasNext() {
        int i = 0;
        for (Iterator stream = this.buildPeekableIterator(); stream.hasNext(); ) {
            stream.next();
            i++;
        }
        assertEquals(6, i);
    }

    public void testNext() {
        Iterator stream = this.buildPeekableIterator();
        assertEquals("zero", stream.next());
        assertEquals("one", stream.next());
        assertEquals("two", stream.next());
        assertEquals("three", stream.next());
        assertEquals("four", stream.next());
        assertEquals("five", stream.next());
    }

    public void testPeek() {
        Object next = null;
        for (PeekableIterator stream = this.buildPeekableIterator(); stream.hasNext(); ) {
            Object peek = stream.peek();
            assertTrue("peek and next are prematurely identical", peek != next);
            next = stream.next();
            assertTrue("peek and next are not identical", peek == next);
        }
    }

    private PeekableIterator buildPeekableIterator() {
        return this.buildPeekableIterator(this.buildNestedIterator());
    }

    private PeekableIterator buildPeekableIterator(Iterator nestedIterator) {
        return new PeekableIterator(nestedIterator);
    }

    private Iterator buildNestedIterator() {
        Collection c = new ArrayList();
        c.add("zero");
        c.add("one");
        c.add("two");
        c.add("three");
        c.add("four");
        c.add("five");
        return c.iterator();
    }

}