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fixing bug in FilterListIterator, adding test for it 

javadoc fixes to FilterListIterator


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@130599 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Rodney Waldhoff 2002-02-26 17:28:55 +00:00
parent 95fbcee471
commit 224a627029
2 changed files with 157 additions and 51 deletions
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91
src/java/org/apache/commons/collections/FilterListIterator.java
View File

@ -1,7 +1,7 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/Attic/FilterListIterator.java,v 1.1 2002/02/25 23:53:20 rwaldhoff Exp $
* $Revision: 1.1 $
* $Date: 2002/02/25 23:53:20 $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/Attic/FilterListIterator.java,v 1.2 2002/02/26 17:28:55 rwaldhoff Exp $
* $Revision: 1.2 $
* $Date: 2002/02/26 17:28:55 $
*
* ====================================================================
*
@ -64,19 +64,21 @@ import java.util.ListIterator;
import java.util.NoSuchElementException;
/**
* A proxy {@link ListIterator ListIterator} which takes a {@link Predicate Predicate} instance to filter
* out objects from an underlying {@link Iterator Iterator} instance.
* Only objects for which the
* specified <code>Predicate</code> evaluates to <code>true</code> are
* returned.
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @author Jan Sorensen
* A proxy {@link ListIterator ListIterator} which
* takes a {@link Predicate Predicate} instance to filter
* out objects from an underlying <code>ListIterator</code>
* instance. Only objects for which the specified
* <code>Predicate</code> evaluates to <code>true</code> are
* returned by the iterator.
*
* @version $Revision: 1.2 $ $Date: 2002/02/26 17:28:55 $
* @author Rodney Waldhoff
*/
public class FilterListIterator extends ProxyListIterator {
// Constructors
//-------------------------------------------------------------------------
public FilterListIterator() {
}
@ -89,9 +91,14 @@ public class FilterListIterator extends ProxyListIterator {
this.predicate = predicate;
}
public FilterListIterator(Predicate predicate) {
this.predicate = predicate;
}
// ListIterator interface
//-------------------------------------------------------------------------
/** Not supported. */
public void add(Object o) {
throw new UnsupportedOperationException("FilterListIterator.add(Object) is not supported.");
}
@ -118,9 +125,10 @@ public class FilterListIterator extends ProxyListIterator {
throw new NoSuchElementException();
}
}
nextObjectSet = false;
nextIndex++;
return nextObject;
Object temp = nextObject;
clearNextObject();
return temp;
}
public int nextIndex() {
@ -133,19 +141,22 @@ public class FilterListIterator extends ProxyListIterator {
throw new NoSuchElementException();
}
}
previousObjectSet = false;
nextIndex--;
return previousObject;
Object temp = previousObject;
clearPreviousObject();
return temp;
}
public int previousIndex() {
return (nextIndex-1);
}
/** Not supported. */
public void remove() {
throw new UnsupportedOperationException("FilterListIterator.remove() is not supported.");
}
/** Not supported. */
public void set(Object o) {
throw new UnsupportedOperationException("FilterListIterator.set(Object) is not supported.");
}
@ -168,14 +179,29 @@ public class FilterListIterator extends ProxyListIterator {
this.predicate = predicate;
}
/**
* Set {@link #nextObject} to the next object. If there
* are no more objects then return <code>false</code>.
* Otherwise, return <code>true</code>.
*/
// Private Methods
//-------------------------------------------------------------------------
private void clearNextObject() {
nextObject = null;
nextObjectSet = false;
}
private boolean setNextObject() {
ListIterator iterator = getListIterator();
Predicate predicate = getPredicate();
// if previousObjectSet,
// then we've walked back one step in the
// underlying list (due to a hasPrevious() call)
// so skip ahead one matching object
if(previousObjectSet) {
clearPreviousObject();
if(!setNextObject()) {
return false;
}
}
while(iterator.hasNext()) {
Object object = iterator.next();
if(predicate.evaluate(object)) {
@ -187,14 +213,26 @@ public class FilterListIterator extends ProxyListIterator {
return false;
}
/**
* Set {@link #nextObject} to the next object. If there
* are no more objects then return <code>false</code>.
* Otherwise, return <code>true</code>.
*/
private void clearPreviousObject() {
previousObject = null;
previousObjectSet = false;
}
private boolean setPreviousObject() {
ListIterator iterator = getListIterator();
Predicate predicate = getPredicate();
// if nextObjectSet,
// then we've walked back one step in the
// underlying list (due to a hasNext() call)
// so skip ahead one matching object
if(nextObjectSet) {
clearNextObject();
if(!setPreviousObject()) {
return false;
}
}
while(iterator.hasPrevious()) {
Object object = iterator.previous();
if(predicate.evaluate(object)) {
@ -224,7 +262,6 @@ public class FilterListIterator extends ProxyListIterator {
*/
private boolean nextObjectSet = false;
/**
* The value of the previous (matching) object, when
* {@link #previousObjectSet} is true.

117
src/test/org/apache/commons/collections/TestFilterListIterator.java
View File

@ -1,7 +1,7 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/Attic/TestFilterListIterator.java,v 1.1 2002/02/25 23:53:20 rwaldhoff Exp $
* $Revision: 1.1 $
* $Date: 2002/02/25 23:53:20 $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/Attic/TestFilterListIterator.java,v 1.2 2002/02/26 17:28:55 rwaldhoff Exp $
* $Revision: 1.2 $
* $Date: 2002/02/26 17:28:55 $
*
* ====================================================================
*
@ -70,7 +70,7 @@ import java.util.ListIterator;
import java.util.Random;
/**
* @version $Revision: 1.1 $ $Date: 2002/02/25 23:53:20 $
* @version $Revision: 1.2 $ $Date: 2002/02/26 17:28:55 $
* @author Rodney Waldhoff
*/
public class TestFilterListIterator extends TestCase {
@ -112,6 +112,7 @@ public class TestFilterListIterator extends TestCase {
list.add(new Integer(i));
if(i%2 == 0) { evens.add(new Integer(i)); }
if(i%2 == 1) { odds.add(new Integer(i)); }
if(i%3 == 0) { threes.add(new Integer(i)); }
if(i%4 == 0) { fours.add(new Integer(i)); }
if(i%6 == 0) { sixes.add(new Integer(i)); }
}
@ -238,7 +239,7 @@ public class TestFilterListIterator extends TestCase {
FilterListIterator filtered = new FilterListIterator(list.listIterator(),truePred);
walkLists(list,filtered);
}
public void testFalsePredicate() {
FilterListIterator filtered = new FilterListIterator(list.listIterator(),falsePred);
walkLists(new ArrayList(),filtered);
@ -280,26 +281,98 @@ public class TestFilterListIterator extends TestCase {
walkLists(sixes,filtered);
}
public void testNestedSixes3() {
FilterListIterator filtered = new FilterListIterator(
new FilterListIterator(list.listIterator(),threePred),
evenPred
);
walkLists(sixes,new FilterListIterator(filtered,truePred));
}
public void testNextChangesPrevious() {
{
FilterListIterator filtered = new FilterListIterator(list.listIterator(),threePred);
nextNextPrevious(threes.listIterator(),filtered);
}
{
FilterListIterator filtered = new FilterListIterator(list.listIterator(),truePred);
nextNextPrevious(list.listIterator(),filtered);
}
}
public void testPreviousChangesNext() {
{
FilterListIterator filtered = new FilterListIterator(list.listIterator(),threePred);
ListIterator expected = threes.listIterator();
walkForward(expected,filtered);
previousPreviousNext(expected,filtered);
}
{
FilterListIterator filtered = new FilterListIterator(list.listIterator(),truePred);
ListIterator expected = list.listIterator();
walkForward(expected,filtered);
previousPreviousNext(expected,filtered);
}
}
// Utilities
private void walkForward(ListIterator expected, ListIterator testing) {
while(expected.hasNext()) {
assertEquals(expected.nextIndex(),testing.nextIndex());
assertEquals(expected.previousIndex(),testing.previousIndex());
assertTrue(testing.hasNext());
assertEquals(expected.next(),testing.next());
}
}
private void walkBackward(ListIterator expected, ListIterator testing) {
while(expected.hasPrevious()) {
assertEquals(expected.nextIndex(),testing.nextIndex());
assertEquals(expected.previousIndex(),testing.previousIndex());
assertTrue(testing.hasPrevious());
assertEquals(expected.previous(),testing.previous());
}
}
private void nextNextPrevious(ListIterator expected, ListIterator testing) {
// calls to next() should change the value returned by previous()
// even after previous() has been set by a call to hasPrevious()
assertEquals(expected.next(),testing.next());
assertEquals(expected.hasPrevious(),testing.hasPrevious());
Object expecteda = expected.next();
Object testinga = testing.next();
assertEquals(expecteda,testinga);
Object expectedb = expected.previous();
Object testingb = testing.previous();
assertEquals(expecteda,expectedb);
assertEquals(testinga,testingb);
}
private void previousPreviousNext(ListIterator expected, ListIterator testing) {
// calls to previous() should change the value returned by next()
// even after next() has been set by a call to hasNext()
assertEquals(expected.previous(),testing.previous());
assertEquals(expected.hasNext(),testing.hasNext());
Object expecteda = expected.previous();
Object testinga = testing.previous();
assertEquals(expecteda,testinga);
Object expectedb = expected.next();
Object testingb = testing.next();
assertEquals(expecteda,testingb);
assertEquals(expecteda,expectedb);
assertEquals(testinga,testingb);
}
private void walkLists(List list, ListIterator testing) {
ListIterator expected = list.listIterator();
// walk all the way forward
while(expected.hasNext()) {
assertEquals(expected.nextIndex(),testing.nextIndex());
assertEquals(expected.previousIndex(),testing.previousIndex());
assertTrue("a",testing.hasNext());
assertEquals("b",expected.next(),testing.next());
}
walkForward(expected,testing);
// walk all the way back
while(expected.hasPrevious()) {
assertEquals(expected.nextIndex(),testing.nextIndex());
assertEquals(expected.previousIndex(),testing.previousIndex());
assertTrue("c",testing.hasPrevious());
assertEquals("d",expected.previous(),testing.previous());
}
walkBackward(expected,testing);
// forward,back,foward
while(expected.hasNext()) {
@ -313,13 +386,9 @@ public class TestFilterListIterator extends TestCase {
assertEquals(expected.next(),testing.next());
}
// walk all the way back
while(expected.hasPrevious()) {
assertEquals(expected.nextIndex(),testing.nextIndex());
assertEquals(expected.previousIndex(),testing.previousIndex());
assertTrue(testing.hasPrevious());
assertEquals(expected.previous(),testing.previous());
}
walkBackward(expected,testing);
for(int i=0;i<list.size();i++) {
// walk forward i