*/
package org.opendaylight.yangtools.concepts;
-import java.util.concurrent.atomic.AtomicBoolean;
+import com.google.common.base.MoreObjects;
+import com.google.common.base.MoreObjects.ToStringHelper;
+import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
/**
- * Utility registration handle. It is a convenience for register-style method
- * which can return an AutoCloseable realized by a subclass of this class.
- * Invoking the close() method triggers unregistration of the state the method
- * installed.
+ * Utility registration handle. It is a convenience for register-style method which can return an AutoCloseable realized
+ * by a subclass of this class. Invoking the close() method triggers unregistration of the state the method installed.
*/
-public abstract class AbstractRegistration implements AutoCloseable {
- private AtomicBoolean closed = new AtomicBoolean();
-
+public abstract class AbstractRegistration implements Registration {
+ private static final AtomicIntegerFieldUpdater<AbstractRegistration> CLOSED_UPDATER =
+ AtomicIntegerFieldUpdater.newUpdater(AbstractRegistration.class, "closed");
+ private volatile int closed = 0;
+
/**
- * Remove the state referenced by this registration. This method is
- * guaranteed to be called at most once. The referenced state must be
- * retained until this method is invoked.
+ * Remove the state referenced by this registration. This method is guaranteed to be called at most once.
+ * Referenced state must be retained until this method is invoked.
*/
protected abstract void removeRegistration();
+ /**
+ * Query the state of this registration. Returns true if it was closed.
+ *
+ * @return true if the registration was closed, false otherwise.
+ */
+ public final boolean isClosed() {
+ return closed != 0;
+ }
+
@Override
public final void close() {
- if (closed.compareAndSet(false, true)) {
+ if (CLOSED_UPDATER.compareAndSet(this, 0, 1)) {
removeRegistration();
}
}
+
+ @Override
+ public final String toString() {
+ return addToStringAttributes(MoreObjects.toStringHelper(this).omitNullValues()).toString();
+ }
+
+ protected ToStringHelper addToStringAttributes(final ToStringHelper toStringHelper) {
+ return toStringHelper.add("closed", closed);
+ }
}