Cursor instance which extends
* ListIterator. The cursor allows changes to the list concurrent
* with changes to the iterator. Note that the {@link #iterator()} method and
- * sublists do not provide this cursor behaviour.
+ * sublists do not provide this cursor behaviour.
*
* The Cursor class is provided partly for backwards compatibility
* and partly because it allows the cursor to be directly closed. Closing the
@@ -374,6 +374,19 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
doReadObject(in);
}
+ //-----------------------------------------------------------------------
+ /**
+ * Creates a list iterator for the sublist.
+ *
+ * @param subList the sublist to get an iterator for
+ * @param fromIndex the index to start from, relative to the sublist
+ */
+ protected ListIterator createSubListListIterator(LinkedSubList subList, int fromIndex) {
+ SubCursor cursor = new SubCursor(subList, fromIndex);
+ registerCursor(cursor);
+ return cursor;
+ }
+
//-----------------------------------------------------------------------
/**
* An extended ListIterator that allows concurrent changes to
@@ -384,6 +397,8 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
boolean valid = true;
/** Is the next index valid */
boolean nextIndexValid = true;
+ /** Flag to indicate if the current element was removed by another object. */
+ boolean currentRemovedByAnother = false;
/**
* Constructs a new cursor.
@@ -394,7 +409,33 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
super(parent, index);
valid = true;
}
-
+
+ /**
+ * Removes the item last returned by this iterator.
+ *
+ * There may have been subsequent alterations to the list
+ * since you obtained this item, however you can still remove it.
+ * You can even remove it if the item is no longer in the main list.
+ * However, you can't call this method on the same iterator more
+ * than once without calling next() or previous().
+ *
+ * @throws IllegalStateException if there is no item to remove
+ */
+ public void remove() {
+ // overridden, as the nodeRemoved() method updates the iterator
+ // state in the parent.removeNode() call below
+ if (current == null && currentRemovedByAnother) {
+ // quietly ignore, as the last returned node was removed
+ // by the list or some other iterator
+ // by ignoring it, we keep this iterator independent from
+ // other changes as much as possible
+ } else {
+ checkModCount();
+ parent.removeNode(getLastNodeReturned());
+ }
+ currentRemovedByAnother = false;
+ }
+
/**
* Adds an object to the list.
* The object added here will be the new 'previous' in the iterator.
@@ -402,10 +443,17 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
* @param obj the object to add
*/
public void add(Object obj) {
+ // overridden, as the nodeInserted() method updates the iterator state
super.add(obj);
- // add on iterator does not return the added element
+ // matches the (next.previous == node) clause in nodeInserted()
+ // thus next gets changed - reset it again here
next = next.next;
}
+
+ // set is not overridden, as it works ok
+ // note that we want it to throw an exception if the element being
+ // set has been removed from the real list (compare this with the
+ // remove method where we silently ignore this case)
/**
* Gets the index of the next element to be returned.
@@ -449,17 +497,21 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
// state where next() followed by previous()
next = node.next;
current = null;
+ currentRemovedByAnother = true;
} else if (node == next) {
// state where next() not followed by previous()
// and we are matching next node
next = node.next;
+ currentRemovedByAnother = false;
} else if (node == current) {
// state where next() not followed by previous()
// and we are matching current (last returned) node
current = null;
+ currentRemovedByAnother = true;
nextIndex--;
} else {
nextIndexValid = false;
+ currentRemovedByAnother = false;
}
}
@@ -502,4 +554,49 @@ public class CursorableLinkedList extends AbstractLinkedList implements Serializ
}
}
}
+
+ //-----------------------------------------------------------------------
+ /**
+ * A cursor for the sublist based on LinkedSubListIterator.
+ */
+ protected static class SubCursor extends Cursor {
+
+ /** The parent list */
+ protected final LinkedSubList sub;
+
+ /**
+ * Constructs a new cursor.
+ *
+ * @param index the index to start from
+ */
+ protected SubCursor(LinkedSubList sub, int index) {
+ super((CursorableLinkedList) sub.parent, index + sub.offset);
+ this.sub = sub;
+ }
+
+ public boolean hasNext() {
+ return (nextIndex() < sub.size);
+ }
+
+ public boolean hasPrevious() {
+ return (previousIndex() >= 0);
+ }
+
+ public int nextIndex() {
+ return (super.nextIndex() - sub.offset);
+ }
+
+ public void add(Object obj) {
+ super.add(obj);
+ sub.expectedModCount = parent.modCount;
+ sub.size++;
+ }
+
+ public void remove() {
+ super.remove();
+ sub.expectedModCount = parent.modCount;
+ sub.size--;
+ }
+ }
+
}
diff --git a/src/java/org/apache/commons/collections/list/TreeList.java b/src/java/org/apache/commons/collections/list/TreeList.java
index 242835267..f76b86ba1 100644
--- a/src/java/org/apache/commons/collections/list/TreeList.java
+++ b/src/java/org/apache/commons/collections/list/TreeList.java
@@ -749,23 +749,20 @@ public class TreeList extends AbstractList {
/** The parent list */
protected final TreeList parent;
/**
- * The node that will be returned by {@link #next()}. If this is equal
- * to {@link AbstractLinkedList#header} then there are no more values to return.
+ * Cache of the next node that will be returned by {@link #next()}.
*/
protected AVLNode next;
/**
- * The index of {@link #next}.
+ * The index of the next node to be returned.
*/
protected int nextIndex;
/**
- * The last node that was returned by {@link #next()} or {@link
- * #previous()}. Set to null if {@link #next()} or {@link
- * #previous()} haven't been called, or if the node has been removed
- * with {@link #remove()} or a new node added with {@link #add(Object)}.
+ * Cache of the last node that was returned by {@link #next()}
+ * or {@link #previous()}.
*/
protected AVLNode current;
/**
- * The index of {@link #current}.
+ * The index of the last node that was returned.
*/
protected int currentIndex;
/**
@@ -788,6 +785,7 @@ public class TreeList extends AbstractList {
this.expectedModCount = parent.modCount;
this.next = (parent.root == null ? null : parent.root.get(fromIndex));
this.nextIndex = fromIndex;
+ this.currentIndex = -1;
}
/**
@@ -852,13 +850,20 @@ public class TreeList extends AbstractList {
public void remove() {
checkModCount();
- if (current == null) {
+ if (currentIndex == -1) {
throw new IllegalStateException();
}
- parent.remove(currentIndex);
+ if (nextIndex == currentIndex) {
+ // remove() following previous()
+ next = next.next();
+ parent.remove(currentIndex);
+ } else {
+ // remove() following next()
+ parent.remove(currentIndex);
+ nextIndex--;
+ }
current = null;
currentIndex = -1;
- nextIndex--;
expectedModCount++;
}
diff --git a/src/test/org/apache/commons/collections/list/AbstractTestList.java b/src/test/org/apache/commons/collections/list/AbstractTestList.java
index 3c8033dd2..f272575f6 100644
--- a/src/test/org/apache/commons/collections/list/AbstractTestList.java
+++ b/src/test/org/apache/commons/collections/list/AbstractTestList.java
@@ -1,5 +1,5 @@
/*
- * Copyright 2001-2004 The Apache Software Foundation
+ * Copyright 2001-2005 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -796,10 +796,11 @@ public abstract class AbstractTestList extends AbstractTestCollection {
}
}
+ //-----------------------------------------------------------------------
/**
* Tests remove on list iterator is correct.
*/
- public void testListListIteratorPreviousRemove() {
+ public void testListListIteratorPreviousRemoveNext() {
if (isRemoveSupported() == false) return;
resetFull();
ListIterator it = getList().listIterator();
@@ -813,11 +814,91 @@ public abstract class AbstractTestList extends AbstractTestCollection {
assertSame(zero, getList().get(0));
assertSame(one, getList().get(1));
assertSame(two, getList().get(2));
- it.remove();
+
+ it.remove(); // removed element at index 1 (one)
assertSame(zero, getList().get(0));
assertSame(two, getList().get(1));
+ Object two3 = it.next(); // do next after remove
+ assertSame(two, two3);
+ assertEquals(collection.size() > 2, it.hasNext());
+ assertEquals(true, it.hasPrevious());
}
+ /**
+ * Tests remove on list iterator is correct.
+ */
+ public void testListListIteratorPreviousRemovePrevious() {
+ if (isRemoveSupported() == false) return;
+ resetFull();
+ ListIterator it = getList().listIterator();
+ Object zero = it.next();
+ Object one = it.next();
+ Object two = it.next();
+ Object two2 = it.previous();
+ Object one2 = it.previous();
+ assertSame(one, one2);
+ assertSame(two, two2);
+ assertSame(zero, getList().get(0));
+ assertSame(one, getList().get(1));
+ assertSame(two, getList().get(2));
+
+ it.remove(); // removed element at index 1 (one)
+ assertSame(zero, getList().get(0));
+ assertSame(two, getList().get(1));
+ Object zero3 = it.previous(); // do previous after remove
+ assertSame(zero, zero3);
+ assertEquals(false, it.hasPrevious());
+ assertEquals(collection.size() > 2, it.hasNext());
+ }
+
+ /**
+ * Tests remove on list iterator is correct.
+ */
+ public void testListListIteratorNextRemoveNext() {
+ if (isRemoveSupported() == false) return;
+ resetFull();
+ ListIterator it = getList().listIterator();
+ Object zero = it.next();
+ Object one = it.next();
+ Object two = it.next();
+ assertSame(zero, getList().get(0));
+ assertSame(one, getList().get(1));
+ assertSame(two, getList().get(2));
+ Object three = getList().get(3);
+
+ it.remove(); // removed element at index 2 (two)
+ assertSame(zero, getList().get(0));
+ assertSame(one, getList().get(1));
+ Object three2 = it.next(); // do next after remove
+ assertSame(three, three2);
+ assertEquals(collection.size() > 3, it.hasNext());
+ assertEquals(true, it.hasPrevious());
+ }
+
+ /**
+ * Tests remove on list iterator is correct.
+ */
+ public void testListListIteratorNextRemovePrevious() {
+ if (isRemoveSupported() == false) return;
+ resetFull();
+ ListIterator it = getList().listIterator();
+ Object zero = it.next();
+ Object one = it.next();
+ Object two = it.next();
+ assertSame(zero, getList().get(0));
+ assertSame(one, getList().get(1));
+ assertSame(two, getList().get(2));
+
+ it.remove(); // removed element at index 2 (two)
+ assertSame(zero, getList().get(0));
+ assertSame(one, getList().get(1));
+ Object one2 = it.previous(); // do previous after remove
+ assertSame(one, one2);
+ assertEquals(true, it.hasNext());
+ assertEquals(true, it.hasPrevious());
+ }
+
+ //-----------------------------------------------------------------------
/**
* Traverses to the end of the given iterator.
*
diff --git a/src/test/org/apache/commons/collections/list/TestCursorableLinkedList.java b/src/test/org/apache/commons/collections/list/TestCursorableLinkedList.java
index b2a9f7a97..843d78e25 100644
--- a/src/test/org/apache/commons/collections/list/TestCursorableLinkedList.java
+++ b/src/test/org/apache/commons/collections/list/TestCursorableLinkedList.java
@@ -460,8 +460,17 @@ public class TestCursorableLinkedList extends TestAbstractLinkedList {
assertEquals(true, c1.nextIndexValid);
assertEquals(1, c1.nextIndex);
+ assertEquals(true, c1.currentRemovedByAnother);
assertEquals(null, c1.current);
assertEquals("C", c1.next.value);
+
+ assertEquals("[A, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
}
public void testInternalState_CursorNextRemoveIndex1ByList() {
@@ -476,8 +485,17 @@ public class TestCursorableLinkedList extends TestAbstractLinkedList {
assertEquals(true, c1.nextIndexValid);
assertEquals(1, c1.nextIndex);
+ assertEquals(false, c1.currentRemovedByAnother);
assertEquals("A", c1.current.value);
assertEquals("C", c1.next.value);
+
+ assertEquals("[A, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
}
public void testInternalState_CursorNextNextRemoveIndex1ByList() {
@@ -493,8 +511,17 @@ public class TestCursorableLinkedList extends TestAbstractLinkedList {
assertEquals(true, c1.nextIndexValid);
assertEquals(1, c1.nextIndex);
+ assertEquals(true, c1.currentRemovedByAnother);
assertEquals(null, c1.current);
assertEquals("C", c1.next.value);
+
+ assertEquals("[A, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
}
public void testInternalState_CursorNextNextNextRemoveIndex1ByList() {
@@ -511,8 +538,267 @@ public class TestCursorableLinkedList extends TestAbstractLinkedList {
assertEquals("B", list.remove(1));
assertEquals(false, c1.nextIndexValid);
+ assertEquals(false, c1.currentRemovedByAnother);
assertEquals("C", c1.current.value);
assertEquals("D", c1.next.value);
+
+ assertEquals("[A, C, D]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, D]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ //-----------------------------------------------------------------------
+ public void testInternalState_CursorNextNextPreviousRemoveByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+ assertEquals("B", c1.previous());
+
+ c1.remove();
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals(false, c1.currentRemovedByAnother);
+ assertEquals(null, c1.current);
+ assertEquals("C", c1.next.value);
+
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ public void testInternalState_CursorNextNextRemoveByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+
+ c1.remove();
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals(false, c1.currentRemovedByAnother);
+ assertEquals(null, c1.current);
+ assertEquals("C", c1.next.value);
+
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ //-----------------------------------------------------------------------
+ public void testInternalState_CursorNextNextPreviousAddIndex1ByList() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+ assertEquals("B", c1.previous());
+
+ list.add(1, "Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals("B", c1.current.value);
+ assertEquals("Z", c1.next.value);
+
+ assertEquals("[A, Z, B, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, Z, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ public void testInternalState_CursorNextAddIndex1ByList() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+
+ list.add(1, "Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals("A", c1.current.value);
+ assertEquals("Z", c1.next.value);
+
+ assertEquals("[A, Z, B, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[Z, B, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ public void testInternalState_CursorNextNextAddIndex1ByList() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+
+ list.add(1, "Z");
+
+ assertEquals(false, c1.nextIndexValid);
+ assertEquals("B", c1.current.value);
+ assertEquals("C", c1.next.value);
+
+ assertEquals("[A, Z, B, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, Z, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ //-----------------------------------------------------------------------
+ public void testInternalState_CursorNextNextPreviousAddByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+ assertEquals("B", c1.previous());
+
+ c1.add("Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(2, c1.nextIndex);
+ assertEquals(null, c1.current);
+ assertEquals("B", c1.next.value);
+
+ assertEquals("[A, Z, B, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ public void testInternalState_CursorNextNextAddByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+
+ c1.add("Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(3, c1.nextIndex);
+ assertEquals(false, c1.currentRemovedByAnother);
+ assertEquals(null, c1.current);
+ assertEquals("C", c1.next.value);
+
+ assertEquals("[A, B, Z, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ //-----------------------------------------------------------------------
+ public void testInternalState_CursorNextNextRemoveByListSetByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+
+ list.remove(1);
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals(null, c1.current);
+ assertEquals("C", c1.next.value);
+ assertEquals("[A, C]", list.toString());
+
+ try {
+ c1.set("Z");
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ //-----------------------------------------------------------------------
+ public void testInternalState_CursorNextNextPreviousSetByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+ assertEquals("B", c1.previous());
+
+ c1.set("Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(1, c1.nextIndex);
+ assertEquals("Z", c1.current.value);
+ assertEquals("Z", c1.next.value);
+
+ assertEquals("[A, Z, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
+ }
+
+ public void testInternalState_CursorNextNextSetByIterator() {
+ list.add("A");
+ list.add("B");
+ list.add("C");
+
+ CursorableLinkedList.Cursor c1 = list.cursor();
+ assertEquals("A", c1.next());
+ assertEquals("B", c1.next());
+
+ c1.set("Z");
+
+ assertEquals(true, c1.nextIndexValid);
+ assertEquals(2, c1.nextIndex);
+ assertEquals("Z", c1.current.value);
+ assertEquals("C", c1.next.value);
+
+ assertEquals("[A, Z, C]", list.toString());
+ c1.remove(); // works ok
+ assertEquals("[A, C]", list.toString());
+ try {
+ c1.remove();
+ fail();
+ } catch (IllegalStateException ex) {}
}
//-----------------------------------------------------------------------