Howdy, This behavior seems a little bit brittle to me. I'd rather have a remove() method that is always consistent. Its function should not depend on order of operations like where hasNext() has been called or not. Unless I'm missing something here?
Yoav Shapira Millennium ChemInformatics >-----Original Message----- >From: Ralph Wagner [mailto:[EMAIL PROTECTED]] >Sent: Thursday, January 30, 2003 3:28 AM >To: [EMAIL PROTECTED] >Subject: [Collections][PATCH] Enable remove in FilterIterator > >> At the moment the commons.collections.iterators.FilterIterator does not >implement the "remove" method. >> The comment says: >> * Always throws UnsupportedOperationException as this class >> * does look-ahead with its internal iterator. >> >> This is only a problem if the "hasNext" method was already called, for >the >other cases the remove operation could be implemented. >> >> Ralph > >Index: FilterIterator.java >=================================================================== >RCS file: /home/cvspublic/jakarta- >commons/collections/src/java/org/apache/commons/collections/iterators/F ilte >rIterator.java,v >retrieving revision 1.2 >diff -u -r1.2 FilterIterator.java >--- FilterIterator.java 2003/01/15 21:45:23 1.2 >+++ FilterIterator.java 2003/01/30 07:04:53 >@@ -69,10 +69,11 @@ > * returned. > * > * @since Commons Collections 1.0 >- * @version $Revision: 1.1.1.1 $ $Date: 2003/01/29 13:40:37 $ >+ * @version $Revision: 1.2 $ $Date: 2003/01/15 21:45:23 $ > * > * @author <a href="mailto:[EMAIL PROTECTED]";>James Strachan</a> > * @author Jan Sorensen >+ * @author Ralph Wagner > */ > public class FilterIterator extends ProxyIterator { > >@@ -150,13 +151,20 @@ > } > > /** >- * Always throws UnsupportedOperationException as this class >- * does look-ahead with its internal iterator. >- * >- * @throws UnsupportedOperationException always >+ * Removes from the underlying collection of the base iterator the >last >+ * element returned by this iterator. >+ * This method can only be called, >+ * if <code>next()</code> was called, but not after >+ * <code>hasNext()</code>, because the <code>hasNext()</code> call >+ * changes the base iterator. >+ * @throws IllegalStateException if <code>hasNext()</code> has already >+ * been called. > */ > public void remove() { >- throw new UnsupportedOperationException(); >+ if (nextObjectSet){ >+ throw new IllegalStateException(); >+ } >+ getIterator().remove(); > } > > >Index: TestFilterIterator.java >=================================================================== >RCS file: /home/cvspublic/jakarta- >commons/collections/src/test/org/apache/commons/collections/iterators/T estF >ilterIterator.java,v >retrieving revision 1.4 >diff -u -r1.4 TestFilterIterator.java >--- TestFilterIterator.java 2002/12/13 12:03:06 1.4 >+++ TestFilterIterator.java 2003/01/30 08:00:33 >@@ -65,13 +65,17 @@ > > import junit.framework.TestSuite; > import junit.framework.Test; >+import java.util.ArrayList; >+import java.util.Arrays; > import java.util.Iterator; >+import java.util.List; > import java.util.NoSuchElementException; > import org.apache.commons.collections.Predicate; > > /** > * > * @author Jan Sorensen >+ * @author Ralph Wagner > */ > public class TestFilterIterator extends TestIterator { > >@@ -81,6 +85,7 @@ > } > > private String[] array; >+ private List list; > private FilterIterator iterator; > /** > * Set up instance variables required by this test case. >@@ -121,7 +126,9 @@ > * @return > */ > public Iterator makeFullIterator() { >- return makePassThroughFilter(new ArrayIterator(array)); >+ array = new String[] { "a", "b", "c" }; >+ list = new ArrayList(Arrays.asList(array)); >+ return makePassThroughFilter(list.iterator()); > } > > public Object makeObject() { >@@ -129,7 +136,7 @@ > } > > public boolean supportsRemove() { >- return false; >+ return true; > } > > >@@ -184,10 +191,20 @@ > assertTrue(i == elements.length - 1 ? !iterator.hasNext() : >iterator.hasNext()); > } > verifyNoMoreElements(); >+ >+ // test removal >+ initIterator(); >+ iterator.setPredicate(pred); >+ if (iterator.hasNext()){ >+ Object last = iterator.next(); >+ iterator.remove(); >+ assertTrue("Base of FilterIterator still contains removed >element.", >+ !list.contains(last)); >+ } > } > > private void initIterator() { >- iterator = makePassThroughFilter(new ArrayIterator(array)); >+ iterator = (FilterIterator) makeFullIterator(); > } > > /** > >_______________________________________________________________________ ____ >___ >Schon wieder Viren-Alarm? Bei WEB.DE FreeMail ist das kein Problem, >hier ist der Virencheck inklusive! >http://freemail.web.de/features/?mc=021158 > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
