/**
* Copyright (c) Rich Hickey. All rights reserved.
* The use and distribution terms for this software are covered by the
* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
* which can be found in the file epl-v10.html at the root of this distribution.
* By using this software in any fashion, you are agreeing to be bound by
* the terms of this license.
* You must not remove this notice, or any other, from this software.
**/
/* rich Jan 1, 2009 */
package clojure.lang;
import java.util.concurrent.atomic.AtomicReference;
final public class Atom extends ARef{
final AtomicReference state;
public Atom(Object state){
this.state = new AtomicReference(state);
}
public Atom(Object state, IPersistentMap meta){
super(meta);
this.state = new AtomicReference(state);
}
public Object deref(){
return state.get();
}
public Object swap(IFn f) throws Exception{
for(; ;)
{
Object v = deref();
Object newv = f.invoke(v);
validate(newv);
if(state.compareAndSet(v, newv))
{
notifyWatches(v, newv);
return newv;
}
}
}
public Object swap(IFn f, Object arg) throws Exception{
for(; ;)
{
Object v = deref();
Object newv = f.invoke(v, arg);
validate(newv);
if(state.compareAndSet(v, newv))
{
notifyWatches(v, newv);
return newv;
}
}
}
public Object swap(IFn f, Object arg1, Object arg2) throws Exception{
for(; ;)
{
Object v = deref();
Object newv = f.invoke(v, arg1, arg2);
validate(newv);
if(state.compareAndSet(v, newv))
{
notifyWatches(v, newv);
return newv;
}
}
}
public Object swap(IFn f, Object x, Object y, ISeq args) throws Exception{
for(; ;)
{
Object v = deref();
Object newv = f.applyTo(RT.listStar(v, x, y, args));
validate(newv);
if(state.compareAndSet(v, newv))
{
notifyWatches(v, newv);
return newv;
}
}
}
public boolean compareAndSet(Object oldv, Object newv){
validate(newv);
boolean ret = state.compareAndSet(oldv, newv);
if(ret)
notifyWatches(oldv, newv);
return ret;
}
public Object reset(Object newval){
Object oldval = state.get();
validate(newval);
state.set(newval);
notifyWatches(oldval, newval);
return newval;
}
}