/* | |
* 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.Iterator; | |
import java.util.NoSuchElementException; | |
import org.apache.commons.collections.AbstractTestObject; | |
/** | |
* Abstract class for testing the Iterator interface. | |
* <p> | |
* This class provides a framework for testing an implementation of Iterator. | |
* Concrete subclasses must provide the iterator to be tested. | |
* They must also specify certain details of how the iterator operates by | |
* overriding the supportsXxx() methods if necessary. | |
* | |
* @since Commons Collections 3.0 | |
* @version $Revision: 646780 $ $Date: 2008-04-10 13:48:07 +0100 (Thu, 10 Apr 2008) $ | |
* | |
* @author Morgan Delagrange | |
* @author Stephen Colebourne | |
*/ | |
public abstract class AbstractTestIterator extends AbstractTestObject { | |
/** | |
* JUnit constructor. | |
* | |
* @param testName the test class name | |
*/ | |
public AbstractTestIterator(String testName) { | |
super(testName); | |
} | |
//----------------------------------------------------------------------- | |
/** | |
* Implement this method to return an iterator over an empty collection. | |
* | |
* @return an empty iterator | |
*/ | |
public abstract Iterator makeEmptyIterator(); | |
/** | |
* Implement this method to return an iterator over a collection with elements. | |
* | |
* @return a full iterator | |
*/ | |
public abstract Iterator makeFullIterator(); | |
/** | |
* Implements the abstract superclass method to return the full iterator. | |
* | |
* @return a full iterator | |
*/ | |
public Object makeObject() { | |
return makeFullIterator(); | |
} | |
/** | |
* Whether or not we are testing an iterator that can be empty. | |
* Default is true. | |
* | |
* @return true if Iterator can be empty | |
*/ | |
public boolean supportsEmptyIterator() { | |
return true; | |
} | |
/** | |
* Whether or not we are testing an iterator that can contain elements. | |
* Default is true. | |
* | |
* @return true if Iterator can be full | |
*/ | |
public boolean supportsFullIterator() { | |
return true; | |
} | |
/** | |
* Whether or not we are testing an iterator that supports remove(). | |
* Default is true. | |
* | |
* @return true if Iterator supports remove | |
*/ | |
public boolean supportsRemove() { | |
return true; | |
} | |
/** | |
* Allows subclasses to add complex cross verification | |
*/ | |
public void verify() { | |
// do nothing | |
} | |
//----------------------------------------------------------------------- | |
/** | |
* Test the empty iterator. | |
*/ | |
public void testEmptyIterator() { | |
if (supportsEmptyIterator() == false) { | |
return; | |
} | |
Iterator it = makeEmptyIterator(); | |
// hasNext() should return false | |
assertEquals("hasNext() should return false for empty iterators", false, it.hasNext()); | |
// next() should throw a NoSuchElementException | |
try { | |
it.next(); | |
fail("NoSuchElementException must be thrown when Iterator is exhausted"); | |
} catch (NoSuchElementException e) { | |
} | |
verify(); | |
assertNotNull(it.toString()); | |
} | |
/** | |
* Test normal iteration behaviour. | |
*/ | |
public void testFullIterator() { | |
if (supportsFullIterator() == false) { | |
return; | |
} | |
Iterator it = makeFullIterator(); | |
// hasNext() must be true (ensure makeFullIterator is correct!) | |
assertEquals("hasNext() should return true for at least one element", true, it.hasNext()); | |
// next() must not throw exception (ensure makeFullIterator is correct!) | |
try { | |
it.next(); | |
} catch (NoSuchElementException e) { | |
fail("Full iterators must have at least one element"); | |
} | |
// iterate through | |
while (it.hasNext()) { | |
it.next(); | |
verify(); | |
} | |
// next() must throw NoSuchElementException now | |
try { | |
it.next(); | |
fail("NoSuchElementException must be thrown when Iterator is exhausted"); | |
} catch (NoSuchElementException e) { | |
} | |
assertNotNull(it.toString()); | |
} | |
/** | |
* Test remove behaviour. | |
*/ | |
public void testRemove() { | |
Iterator it = makeFullIterator(); | |
if (supportsRemove() == false) { | |
// check for UnsupportedOperationException if not supported | |
try { | |
it.remove(); | |
} catch (UnsupportedOperationException ex) {} | |
return; | |
} | |
// should throw IllegalStateException before next() called | |
try { | |
it.remove(); | |
fail(); | |
} catch (IllegalStateException ex) {} | |
verify(); | |
// remove after next should be fine | |
it.next(); | |
it.remove(); | |
// should throw IllegalStateException for second remove() | |
try { | |
it.remove(); | |
fail(); | |
} catch (IllegalStateException ex) {} | |
} | |
} |