import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
import java.util.Optional;
-import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.yangtools.yang.binding.DataObject;
* @param <T> DataObject type
*/
public abstract class CodecDataObject<T extends DataObject> implements DataObject {
+ // An object representing a null value in a member field.
private static final @NonNull Object NULL_VALUE = new Object();
+ private static final VarHandle CACHED_HASH_CODE;
+
+ static {
+ try {
+ CACHED_HASH_CODE = MethodHandles.lookup().findVarHandle(CodecDataObject.class, "cachedHashcode",
+ Integer.class);
+ } catch (NoSuchFieldException | IllegalAccessException e) {
+ throw new ExceptionInInitializerError(e);
+ }
+ }
+
+ private final @NonNull DataObjectCodecContext<T, ?> context;
@SuppressWarnings("rawtypes")
private final @NonNull NormalizedNodeContainer data;
- private volatile Integer cachedHashcode = null;
+ // Accessed via a VarHandle
+ @SuppressWarnings("unused")
+ // FIXME: consider using a primitive int-based cache (with 0 being uninit)
+ private volatile Integer cachedHashcode;
- protected CodecDataObject(final NormalizedNodeContainer<?, ?, ?> data) {
+ protected CodecDataObject(final DataObjectCodecContext<T, ?> context, final NormalizedNodeContainer<?, ?, ?> data) {
this.data = requireNonNull(data, "Data must not be null");
+ this.context = requireNonNull(context, "Context must not be null");
}
@Override
public final int hashCode() {
- final Integer cached = cachedHashcode;
- if (cached != null) {
- return cached;
- }
-
- final int result = codecAugmentedHashCode();
- cachedHashcode = result;
- return result;
+ final Integer cached = (Integer) CACHED_HASH_CODE.getAcquire(this);
+ return cached != null ? cached : loadHashCode();
}
@Override
+ @SuppressFBWarnings(value = "EQ_UNUSUAL", justification = "State is examined indirectly enough to confuse SpotBugs")
public final boolean equals(final Object obj) {
if (obj == this) {
return true;
}
@SuppressWarnings("unchecked")
final T other = (T) iface.cast(obj);
- if (other instanceof CodecDataObject) {
- return data.equals(((CodecDataObject<?>) obj).data);
- }
+ // Note: we do not want to compare NormalizedNode data here, as we may be looking at different instantiations
+ // of the same grouping -- in which case normalized node will not compare as equal.
return codecAugmentedEquals(other);
}
.toString();
}
- // TODO: consider switching to VarHandles for Java 9+, as that would disconnect us from the need to use a volatile
- // field and use acquire/release mechanics -- see http://gee.cs.oswego.edu/dl/html/j9mm.html for details.
- protected final Object codecMember(final AtomicReferenceFieldUpdater<CodecDataObject<?>, Object> updater,
- final NodeContextSupplier supplier) {
- final Object cached = updater.get(this);
- return cached != null ? unmaskNull(cached) : loadMember(updater, supplier);
+ protected final Object codecMember(final VarHandle handle, final String localName) {
+ final Object cached = handle.getAcquire(this);
+ return cached != null ? unmaskNull(cached) : loadMember(handle, context.getLeafChild(localName));
}
- protected final Object codecMember(final AtomicReferenceFieldUpdater<CodecDataObject<?>, Object> updater,
- final IdentifiableItemCodec codec) {
- final Object cached = updater.get(this);
- return cached != null ? unmaskNull(cached) : loadKey(updater, codec);
+ protected final Object codecMember(final VarHandle handle, final Class<? extends DataObject> bindingClass) {
+ final Object cached = handle.getAcquire(this);
+ return cached != null ? unmaskNull(cached) : loadMember(handle, context.streamChild(bindingClass));
+ }
+
+ protected final Object codecMember(final VarHandle handle, final NodeContextSupplier supplier) {
+ final Object cached = handle.getAcquire(this);
+ return cached != null ? unmaskNull(cached) : loadMember(handle, supplier.get());
+ }
+
+ protected final Object codecKey(final VarHandle handle) {
+ final Object cached = handle.getAcquire(this);
+ return cached != null ? cached : loadKey(handle);
}
protected abstract int codecHashCode();
protected abstract ToStringHelper codecFillToString(ToStringHelper helper);
+ final @NonNull DataObjectCodecContext<T, ?> codecContext() {
+ return context;
+ }
+
@SuppressWarnings("rawtypes")
final @NonNull NormalizedNodeContainer codecData() {
return data;
return codecFillToString(helper);
}
- // Helpers split out of codecMember to aid its inlining
- private Object loadMember(final AtomicReferenceFieldUpdater<CodecDataObject<?>, Object> updater,
- final NodeContextSupplier supplier) {
- final NodeCodecContext context = supplier.get();
-
+ // Helper split out of codecMember to aid its inlining
+ private Object loadMember(final VarHandle handle, final NodeCodecContext childCtx) {
@SuppressWarnings("unchecked")
- final Optional<NormalizedNode<?, ?>> child = data.getChild(context.getDomPathArgument());
+ final Optional<NormalizedNode<?, ?>> child = data.getChild(childCtx.getDomPathArgument());
// We do not want to use Optional.map() here because we do not want to invoke defaultObject() when we have
// normal value because defaultObject() may end up throwing an exception intentionally.
- return updateCache(updater, child.isPresent() ? context.deserializeObject(child.get())
- : context.defaultObject());
+ final Object obj = child.isPresent() ? childCtx.deserializeObject(child.get()) : childCtx.defaultObject();
+ final Object witness = handle.compareAndExchangeRelease(this, null, maskNull(obj));
+ return witness == null ? obj : unmaskNull(witness);
}
- // Helpers split out of codecMember to aid its inlining
- private Object loadKey(final AtomicReferenceFieldUpdater<CodecDataObject<?>, Object> updater,
- final IdentifiableItemCodec codec) {
+ // Helper split out of codecKey to aid its inlining
+ private Object loadKey(final VarHandle handle) {
verify(data instanceof MapEntryNode, "Unsupported value %s", data);
- return updateCache(updater, codec.deserialize(((MapEntryNode) data).getIdentifier()).getKey());
+ verify(context instanceof KeyedListNodeCodecContext, "Unexpected context %s", context);
+ final Object obj = ((KeyedListNodeCodecContext<?>) context).deserialize(((MapEntryNode) data).getIdentifier());
+ // key is known to be non-null, no need to mask it
+ final Object witness = handle.compareAndExchangeRelease(this, null, obj);
+ return witness == null ? obj : witness;
}
- private Object updateCache(final AtomicReferenceFieldUpdater<CodecDataObject<?>, Object> updater,
- final Object obj) {
- return updater.compareAndSet(this, null, maskNull(obj)) ? obj : unmaskNull(updater.get(this));
+ // Helper split out of hashCode() to aid its inlining
+ private int loadHashCode() {
+ final int result = codecAugmentedHashCode();
+ final Object witness = CACHED_HASH_CODE.compareAndExchangeRelease(this, null, Integer.valueOf(result));
+ return witness == null ? result : (Integer) witness;
}
private static @NonNull Object maskNull(final @Nullable Object unmasked) {
Code Review / mdsal.git / blobdiff