/**
* Remove the value which is associated with the given key. If the key does not exist, this method
* simply ignores the operation.
*
* @param key key whose associated value is to be removed
* @return object which was associated with the given key, or <code>null</code> if no association
* existed with given key.
*/
Object remove(Object key) throws IOException {
int hash = hashCode(key);
long child_recid = _children[hash];
if (child_recid == 0) {
// not bucket/page --> not found
return null;
} else {
HashNode node = (HashNode) _recman.fetch(child_recid, tree.SERIALIZER);
// System.out.println("HashDirectory.remove() child is : "+node);
if (node instanceof HashDirectory) {
// recurse into next directory level
HashDirectory dir = (HashDirectory) node;
dir.setPersistenceContext(_recman, child_recid);
Object existing = dir.remove(key);
if (existing != null) {
if (dir.isEmpty()) {
// delete empty directory
_recman.delete(child_recid);
_children[hash] = 0;
_recman.update(_recid, this, tree.SERIALIZER);
}
}
return existing;
} else {
// node is a bucket
HashBucket bucket = (HashBucket) node;
Object existing = bucket.removeElement(key);
if (existing != null) {
if (bucket.getElementCount() >= 1) {
_recman.update(child_recid, bucket, tree.SERIALIZER);
} else {
// delete bucket, it's empty
_recman.delete(child_recid);
_children[hash] = 0;
_recman.update(_recid, this, tree.SERIALIZER);
}
}
return existing;
}
}
}
