2 * Copyright (c) 2019 PANTHEON.tech, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.mdsal.binding.dom.codec.impl;
10 import static com.google.common.base.Verify.verify;
11 import static java.util.Objects.requireNonNull;
13 import java.lang.invoke.MethodHandles;
14 import java.lang.invoke.VarHandle;
15 import java.util.Optional;
16 import org.eclipse.jdt.annotation.NonNull;
17 import org.eclipse.jdt.annotation.Nullable;
18 import org.opendaylight.yangtools.yang.binding.DataObject;
19 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
20 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
21 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNodeContainer;
24 * A base class for {@link DataObject}s backed by {@link DataObjectCodecContext}. While this class is public, it not
25 * part of API surface and is an implementation detail. The only reason for it being public is that it needs to be
26 * accessible by code generated at runtime.
28 * @param <T> DataObject type
30 public abstract class CodecDataObject<T extends DataObject> implements DataObject {
31 // An object representing a null value in a member field.
32 private static final @NonNull Object NULL_VALUE = new Object();
34 private static final VarHandle CACHED_HASH_CODE;
38 CACHED_HASH_CODE = MethodHandles.lookup().findVarHandle(CodecDataObject.class, "cachedHashcode",
40 } catch (NoSuchFieldException | IllegalAccessException e) {
41 throw new ExceptionInInitializerError(e);
45 private final @NonNull DataObjectCodecContext<T, ?> context;
46 @SuppressWarnings("rawtypes")
47 private final @NonNull NormalizedNodeContainer data;
49 // Accessed via a VarHandle
50 @SuppressWarnings("unused")
51 // FIXME: consider using a primitive int-based cache (with 0 being uninit)
52 private volatile Integer cachedHashcode;
54 protected CodecDataObject(final DataObjectCodecContext<T, ?> context, final NormalizedNodeContainer<?, ?, ?> data) {
55 this.data = requireNonNull(data, "Data must not be null");
56 this.context = requireNonNull(context, "Context must not be null");
60 public final int hashCode() {
61 final Integer cached = (Integer) CACHED_HASH_CODE.getAcquire(this);
62 return cached != null ? cached : loadHashCode();
66 public final boolean equals(final Object obj) {
67 // Indirection to keep checkstyle happy
68 return codecEquals(obj);
72 public abstract String toString();
74 protected final Object codecMember(final VarHandle handle, final String localName) {
75 final Object cached = handle.getAcquire(this);
76 return cached != null ? unmaskNull(cached) : loadMember(handle, context.getLeafChild(localName));
79 protected final Object codecMember(final VarHandle handle, final Class<? extends DataObject> bindingClass) {
80 final Object cached = handle.getAcquire(this);
81 return cached != null ? unmaskNull(cached) : loadMember(handle, context.streamChild(bindingClass));
84 protected final Object codecMember(final VarHandle handle, final NodeContextSupplier supplier) {
85 final Object cached = handle.getAcquire(this);
86 return cached != null ? unmaskNull(cached) : loadMember(handle, supplier.get());
89 protected final @NonNull Object codecKey(final VarHandle handle) {
90 final Object cached = handle.getAcquire(this);
91 return cached != null ? cached : loadKey(handle);
94 protected abstract int codecHashCode();
96 protected abstract boolean codecEquals(Object obj);
98 final @NonNull DataObjectCodecContext<T, ?> codecContext() {
102 @SuppressWarnings("rawtypes")
103 final @NonNull NormalizedNodeContainer codecData() {
107 // Helper split out of codecMember to aid its inlining
108 private Object loadMember(final VarHandle handle, final NodeCodecContext childCtx) {
109 @SuppressWarnings("unchecked")
110 final Optional<NormalizedNode<?, ?>> child = data.getChild(childCtx.getDomPathArgument());
112 // We do not want to use Optional.map() here because we do not want to invoke defaultObject() when we have
113 // normal value because defaultObject() may end up throwing an exception intentionally.
114 final Object obj = child.isPresent() ? childCtx.deserializeObject(child.get()) : childCtx.defaultObject();
115 final Object witness = handle.compareAndExchangeRelease(this, null, maskNull(obj));
116 return witness == null ? obj : unmaskNull(witness);
119 // Helper split out of codecKey to aid its inlining
120 private @NonNull Object loadKey(final VarHandle handle) {
121 verify(data instanceof MapEntryNode, "Unsupported value %s", data);
122 verify(context instanceof KeyedListNodeCodecContext, "Unexpected context %s", context);
123 final Object obj = ((KeyedListNodeCodecContext<?, ?>) context)
124 .deserialize(((MapEntryNode) data).getIdentifier());
125 // key is known to be non-null, no need to mask it
126 final Object witness = handle.compareAndExchangeRelease(this, null, obj);
127 return witness == null ? obj : witness;
130 // Helper split out of hashCode() to aid its inlining
131 private int loadHashCode() {
132 final int result = codecHashCode();
133 final Object witness = CACHED_HASH_CODE.compareAndExchangeRelease(this, null, Integer.valueOf(result));
134 return witness == null ? result : (Integer) witness;
137 private static @NonNull Object maskNull(final @Nullable Object unmasked) {
138 return unmasked == null ? NULL_VALUE : unmasked;
141 private static @Nullable Object unmaskNull(final Object masked) {
142 return masked == NULL_VALUE ? null : masked;