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Slight optimizations to putAll() and flush() and added a comment

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as to why the algorithm in flush() even properly flushes in LRU order.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1144 6335cc39-0255-0410-8fd6-9bcaacd3b74c
This commit is contained in:
ray
2003-06-05 18:02:24 +00:00
parent 95fa0e517d
commit 3c8108a010
1 changed files with 29 additions and 22 deletions
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projects/samskivert/src/java/com/samskivert/util/LRUHashMap.java
+29 -22
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@@ -1,5 +1,5 @@
//
// $Id: LRUHashMap.java,v 1.5 2003/04/27 07:37:32 mdb Exp $
// $Id: LRUHashMap.java,v 1.6 2003/06/05 18:02:24 ray Exp $
package com.samskivert.util;
@@ -172,9 +172,7 @@ public class LRUHashMap implements Map
// updated our computed "size"
_size += _sizer.computeSize(value);
if (result != null) {
_size -= _sizer.computeSize(result);
}
entryRemoved(result);
// System.out.println("Added " + value + ": " + _size);
// flush if needed
@@ -193,37 +191,46 @@ public class LRUHashMap implements Map
return;
}
// if we've exceeded our size, remove things until we're back
// under the required size; but don't freak out if we have one
// *really* big item
// int removed = 0;
while (_size > _maxSize && size() > 1) {
Object key = keySet().iterator().next();
remove(key);
// removed += _sizer.computeSize(remove(key));
// If we've exceeded our size, remove things until we're back
// under the required size.
if (_size > _maxSize) {
// This works because the entrySet iterator of a LinkedHashMap
// returns the entries in LRU order
Iterator iter = entrySet().iterator();
// don't remove the last entry, even if it's too big, because
// a cache with nothing in it sucks
for (int ii=size(); (ii > 1) && (_size > _maxSize); ii--) {
Map.Entry entry = (Map.Entry) iter.next();
entryRemoved(entry.getValue());
iter.remove();
}
}
}
/**
* Adjust our size to reflect the removal of the specified entry.
*/
protected void entryRemoved (Object entry)
{
if (entry != null) {
_size -= _sizer.computeSize(entry);
}
// if (removed > 0) {
// System.out.println("Removed " + removed + ": " + _size);
// }
}
// documentation inherited from interface
public Object remove (Object key)
{
Object removed = _delegate.remove(key);
if (removed != null) {
_size -= _sizer.computeSize(removed);
}
entryRemoved(removed);
return removed;
}
// documentation inherited from interface
public void putAll (Map t)
{
Iterator i = t.keySet().iterator();
while (i.hasNext()) {
Object key = i.next();
put(key, t.get(key));
for (Iterator iter = t.entrySet().iterator(); iter.hasNext(); ) {
Map.Entry entry = (Map.Entry) iter.next();
put(entry.getKey(), entry.getValue());
}
}