com.sun.hk2.component.SingletonInhabitant Maven / Gradle / Ivy
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package com.sun.hk2.component;
import org.jvnet.hk2.component.Creator;
import org.jvnet.hk2.component.Singleton;
import org.jvnet.hk2.component.Inhabitant;
import org.jvnet.hk2.tracing.TracingThreadLocal;
import org.jvnet.hk2.tracing.TracingUtilities;
/**
* Specialized implementation of {@link ScopedInhabitant} for {@link Singleton}.
* @author Kohsuke Kawaguchi
*/
public class SingletonInhabitant extends AbstractCreatorInhabitantImpl {
private volatile T object;
public SingletonInhabitant(Creator creator) {
super(creator);
}
@SuppressWarnings("unchecked")
public T get(Inhabitant onBehalfOf) {
if(object==null) {
synchronized(this) {
if(object==null) {
try {
if (TracingUtilities.isEnabled())
TracingThreadLocal.get().push(this);
object = creator.get(onBehalfOf);
} finally {
if (TracingUtilities.isEnabled())
TracingThreadLocal.get().pop();
}
}
}
}
return object;
}
public void release() {
if (object!=null) {
synchronized (this) {
dispose(object);
object=null;
}
}
}
public boolean isInstantiated() {
return object!=null;
}
}