| /* |
| * Copyright 2001-2004 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. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.axis.utils ; |
| |
| import java.util.Hashtable; |
| import java.util.Vector; |
| import java.util.Set; |
| import java.util.HashSet; |
| |
| // fixme: Is there a reason to use Hashtable rather than Map here? |
| /** |
| * This subclass of the java Hashtable allows individual |
| * entries to be "locked" so that their values cannot be |
| * overwritten or removed. |
| * |
| * Note, only the put() and remove() methods have been |
| * overridden. The clear() method still removes all |
| * entries whether they've been locked or not. |
| * |
| * @author James Snell (jasnell@us.ibm.com) |
| */ |
| public class LockableHashtable extends Hashtable { |
| |
| // fixme - we are potentialy synchronizing on /both/ the current Hashtable |
| // and also the Vector - a non-synchronizing List impl such as ArrayList |
| // may give better performance. We are doing lots of .contains on this |
| // Vector - it would probably be better to use a Set impl |
| /** |
| * Stores the keys of the locked entries |
| */ |
| Vector lockedEntries; |
| |
| /** Place to look for properties which we don't find locally. */ |
| private Hashtable parent = null; |
| |
| public LockableHashtable() { |
| super(); |
| } |
| |
| public LockableHashtable(int p1, float p2) { |
| super(p1, p2); |
| } |
| |
| public LockableHashtable(java.util.Map p1) { |
| super(p1); |
| } |
| |
| public LockableHashtable(int p1) { |
| super(p1); |
| } |
| |
| /** |
| * Set the parent Hashtable for this object |
| */ |
| public synchronized void setParent(Hashtable parent) |
| { |
| this.parent = parent; |
| } |
| |
| /** |
| * Gets the parent Hashtable for this object (if any) |
| */ |
| public synchronized Hashtable getParent() { |
| return parent; |
| } |
| |
| /** |
| * Returns the keys in this hashtable, and its parent chain |
| */ |
| public Set getAllKeys() { |
| HashSet set = new HashSet(); |
| set.addAll(super.keySet()); |
| Hashtable p = parent; |
| while (p != null) { |
| set.addAll(p.keySet()); |
| if (p instanceof LockableHashtable) { |
| p = ((LockableHashtable) p).getParent(); |
| } else { |
| p = null; |
| } |
| } |
| return set; |
| } |
| |
| /** |
| * Get an entry from this hashtable, and if we don't find anything, |
| * defer to our parent, if any. |
| */ |
| public synchronized Object get(Object key) { |
| Object ret = super.get(key); |
| if ((ret == null) && (parent != null)) { |
| ret = parent.get(key); |
| } |
| return ret; |
| } |
| /** |
| * New version of the put() method that allows for explicitly marking |
| * items added to the hashtable as locked. |
| */ |
| public synchronized Object put(Object p1, Object p2, boolean locked) { |
| if (lockedEntries != null && |
| this.containsKey(p1) && |
| lockedEntries.contains(p1)) { |
| return null; |
| } |
| if (locked) { |
| if (lockedEntries == null) { |
| lockedEntries = new Vector(); |
| } |
| lockedEntries.add(p1); |
| } |
| return super.put(p1, p2); |
| } |
| |
| /** |
| * Overrides the Hashtable.put() method to mark items as not being locked. |
| */ |
| public synchronized Object put(Object p1, Object p2) { |
| return put(p1, p2, false); |
| } |
| |
| /** |
| * Checks to see if an item is locked before it is removed. |
| */ |
| public synchronized Object remove(Object p1) { |
| if (lockedEntries != null && lockedEntries.contains(p1)) { |
| return null; |
| } |
| return super.remove(p1); |
| } |
| |
| /** |
| * Returns true if a given key is in our locked list |
| */ |
| public boolean isKeyLocked(Object key) |
| { |
| return lockedEntries != null && lockedEntries.contains(key); |
| } |
| } |