ChainIteratorTests.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.AbstractCollection;
import java.util.AbstractList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Vector;

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

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

public class ChainIteratorTests extends TestCase {
    private final static Class[] VECTOR_HIERARCHY =
        {Vector.class, AbstractList.class, AbstractCollection.class, Object.class};

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

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

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

    public void testInnerHasNext() {
        int i = 0;
        for (Iterator stream = this.buildInnerIterator(); stream.hasNext(); ) {
            stream.next();
            i++;
        }
        assertEquals(VECTOR_HIERARCHY.length, i);
    }

    public void testNext() {
        int i = 0;
        for (Iterator stream = this.buildIterator(); stream.hasNext(); i++) {
            assertEquals("bogus link", VECTOR_HIERARCHY[i], stream.next());
        }
    }

    public void testInnerNext() {
        int i = 0;
        for (Iterator stream = this.buildInnerIterator(); stream.hasNext(); i++) {
            assertEquals("bogus link", VECTOR_HIERARCHY[i], stream.next());
        }
    }

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

    public void testUnsupportedOperationException() {
        boolean exCaught = false;
        for (Iterator stream = this.buildIterator(); stream.hasNext(); ) {
            if (stream.next() == AbstractCollection.class) {
                try {
                    stream.remove();
                } catch (UnsupportedOperationException ex) {
                    exCaught = true;
                }
            }
        }
        assertTrue("UnsupportedOperationException not thrown", exCaught);
    }

    private Iterator buildIterator() {
        return this.buildChainIterator(Vector.class, this.buildLinker());
    }

    private Iterator buildInnerIterator() {
        return this.buildInnerChainIterator(Vector.class);
    }

    private Iterator buildChainIterator(Class startLink, ChainIterator.Linker linker) {
        return new ChainIterator(startLink, linker);
    }

    private ChainIterator.Linker buildLinker() {
        // chain up the class's hierarchy
        return new ChainIterator.Linker() {
            public Object nextLink(Object currentLink) {
                return ((Class) currentLink).getSuperclass();
            }
        };
    }

    private Iterator buildInnerChainIterator(Class startLink) {
        // chain up the class's hierarchy
        return new ChainIterator(startLink) {
            protected Object nextLink(Object currentLink) {
                return ((Class) currentLink).getSuperclass();
            }
        };
    }

}