/*
* 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.ListIterator;
import java.util.NoSuchElementException;
import junit.framework.Test;
import junit.framework.TestSuite;
import junit.textui.TestRunner;
import org.apache.commons.collections.ResettableListIterator;
/**
* Tests the ReverseListIterator.
*
* @version $Revision: $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $
*/
public class TestReverseListIterator extends AbstractTestListIterator {
protected String[] testArray = { "One", "Two", "Three", "Four" };
public static void main(String args[]) {
String[] testCaseName = { TestReverseListIterator.class.getName() };
TestRunner.main(testCaseName);
}
public static Test suite() {
return new TestSuite(TestReverseListIterator.class);
}
public TestReverseListIterator(String testName) {
super(testName);
}
public ListIterator makeEmptyListIterator() {
List list = new ArrayList();
return new ReverseListIterator(list);
}
public ListIterator makeFullListIterator() {
List list = new ArrayList(Arrays.asList(testArray));
return new ReverseListIterator(list);
}
// overrides
//-----------------------------------------------------------------------
public void testEmptyListIteratorIsIndeedEmpty() {
ListIterator it = makeEmptyListIterator();
assertEquals(false, it.hasNext());
assertEquals(-1, it.nextIndex()); // reversed index
assertEquals(false, it.hasPrevious());
assertEquals(0, it.previousIndex()); // reversed index
// next() should throw a NoSuchElementException
try {
it.next();
fail("NoSuchElementException must be thrown from empty ListIterator");
} catch (NoSuchElementException e) {
}
// previous() should throw a NoSuchElementException
try {
it.previous();
fail("NoSuchElementException must be thrown from empty ListIterator");
} catch (NoSuchElementException e) {
}
}
public void testWalkForwardAndBack() {
ArrayList list = new ArrayList();
ListIterator it = makeFullListIterator();
while (it.hasNext()) {
list.add(it.next());
}
// check state at end
assertEquals(false, it.hasNext());
assertEquals(true, it.hasPrevious());
// this had to be commented out, as there is a bug in the JDK before JDK1.5
// where calling previous at the start of an iterator would push the cursor
// back to an invalid negative value
// try {
// it.next();
// fail("NoSuchElementException must be thrown from next at end of ListIterator");
// } catch (NoSuchElementException e) {
// }
// loop back through comparing
for (int i = list.size() - 1; i >= 0; i--) {
assertEquals("" + i, list.size() - i - 2, it.nextIndex()); // reversed index
assertEquals(list.size() - i - 1, it.previousIndex()); // reversed index
Object obj = list.get(i);
assertEquals(obj, it.previous());
}
// check state at start
assertEquals(true, it.hasNext());
assertEquals(false, it.hasPrevious());
try {
it.previous();
fail("NoSuchElementException must be thrown from previous at start of ListIterator");
} catch (NoSuchElementException e) {
}
}
//-----------------------------------------------------------------------
public void testReverse() {
ListIterator it = makeFullListIterator();
assertEquals(true, it.hasNext());
assertEquals(3, it.nextIndex());
assertEquals(false, it.hasPrevious());
assertEquals(4, it.previousIndex());
assertEquals("Four", it.next());
assertEquals(2, it.nextIndex());
assertEquals(true, it.hasNext());
assertEquals(3, it.previousIndex());
assertEquals(true, it.hasPrevious());
assertEquals("Three", it.next());
assertEquals(true, it.hasNext());
assertEquals(1, it.nextIndex());
assertEquals(true, it.hasPrevious());
assertEquals(2, it.previousIndex());
assertEquals("Two", it.next());
assertEquals(true, it.hasNext());
assertEquals(0, it.nextIndex());
assertEquals(true, it.hasPrevious());
assertEquals(1, it.previousIndex());
assertEquals("One", it.next());
assertEquals(false, it.hasNext());
assertEquals(-1, it.nextIndex());
assertEquals(true, it.hasPrevious());
assertEquals(0, it.previousIndex());
assertEquals("One", it.previous());
assertEquals("Two", it.previous());
assertEquals("Three", it.previous());
assertEquals("Four", it.previous());
}
public void testReset() {
ResettableListIterator it = (ResettableListIterator) makeFullListIterator();
assertEquals("Four", it.next());
it.reset();
assertEquals("Four", it.next());
it.next();
it.next();
it.reset();
assertEquals("Four", it.next());
}
}