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clone() fixes for TreeMap & TreeSet
- To: java-patches at gcc dot gnu dot org, classpath at gnu dot org
- Subject: clone() fixes for TreeMap & TreeSet
- From: Bryce McKinlay <bryce at albatross dot co dot nz>
- Date: Fri, 16 Feb 2001 14:55:19 +1300
Jon Zeppieri (Thanks Jon!) pointed out the clone() implementations in the new TreeMap and
TreeSet were incorrect in the presence of subclassing. I was using "new" to create the
copies instead of super.clone(), which would result in a ClassCastException when someone
called clone() on a subclass, because the type of the Object returned from clone would not
be what was expected.
This patch fixes the problem.
regards
[ bryce ]
2001-02-16 Bryce McKinlay <bryce@albatross.co.nz>
* java/util/TreeSet.java (clone): Made subclass safe, use
super.clone(), not new.
* java/util/TreeMap.java (clone): Likewise.
Index: java/util/TreeMap.java
===================================================================
RCS file: /cvs/gcc/egcs/libjava/java/util/TreeMap.java,v
retrieving revision 1.2
diff -u -r1.2 TreeMap.java
--- TreeMap.java 2001/02/14 05:32:31 1.2
+++ TreeMap.java 2001/02/16 01:40:41
@@ -178,8 +178,14 @@
public Object clone()
{
- TreeMap copy = new TreeMap();
- copy.comparator = comparator;
+ TreeMap copy = null;
+ try
+ {
+ copy = (TreeMap) super.clone();
+ }
+ catch (CloneNotSupportedException x)
+ {
+ }
copy.fabricateTree(size);
Node node = firstNode();
@@ -991,6 +997,9 @@
parent.right = node;
parent = nextparent;
}
+
+ // We use the "right" link to maintain a chain of nodes in
+ // each row until the parent->child links are established.
if (last != null)
last.right = node;
last = node;
Index: java/util/TreeSet.java
===================================================================
RCS file: /cvs/gcc/egcs/libjava/java/util/TreeSet.java,v
retrieving revision 1.2
diff -u -r1.2 TreeSet.java
--- TreeSet.java 2001/02/15 03:59:57 1.2
+++ TreeSet.java 2001/02/16 01:40:41
@@ -157,7 +157,14 @@
/** Returns a shallow copy of this Set. */
public Object clone()
{
- TreeSet copy = new TreeSet();
+ TreeSet copy = null;
+ try
+ {
+ copy = (TreeSet) super.clone();
+ }
+ catch (CloneNotSupportedException x)
+ {
+ }
copy.map = (SortedMap) ((TreeMap) map).clone();
return copy;
}