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 java.util.Objects.requireNonNull;
12 import com.google.common.base.VerifyException;
13 import java.lang.invoke.MethodHandles;
14 import java.lang.invoke.VarHandle;
15 import org.eclipse.jdt.annotation.NonNull;
16 import org.eclipse.jdt.annotation.Nullable;
17 import org.opendaylight.yangtools.yang.binding.DataObject;
18 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
19 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
22 * A base class for {@link DataObject}s backed by {@link DataObjectCodecContext}. While this class is public, it not
23 * part of API surface and is an implementation detail. The only reason for it being public is that it needs to be
24 * accessible by code generated at runtime.
26 * @param <T> DataObject type
28 public abstract class CodecDataObject<T extends DataObject> implements DataObject {
29 // An object representing a null value in a member field.
30 private static final @NonNull Object NULL_VALUE = new Object();
32 private static final VarHandle CACHED_HASH_CODE;
36 CACHED_HASH_CODE = MethodHandles.lookup().findVarHandle(CodecDataObject.class, "cachedHashcode",
38 } catch (NoSuchFieldException | IllegalAccessException e) {
39 throw new ExceptionInInitializerError(e);
43 private final @NonNull AbstractDataObjectCodecContext<T, ?> context;
44 private final @NonNull DataContainerNode data;
46 // Accessed via a VarHandle
47 @SuppressWarnings("unused")
48 // FIXME: consider using a primitive int-based cache (with 0 being uninit)
49 private volatile Integer cachedHashcode;
51 protected CodecDataObject(final AbstractDataObjectCodecContext<T, ?> context, final DataContainerNode data) {
52 this.data = requireNonNull(data, "Data must not be null");
53 this.context = requireNonNull(context, "Context must not be null");
57 public final int hashCode() {
58 final var cached = (Integer) CACHED_HASH_CODE.getAcquire(this);
59 return cached != null ? cached : loadHashCode();
63 public final boolean equals(final Object obj) {
64 // Indirection to keep checkstyle happy
65 return codecEquals(obj);
69 public abstract String toString();
71 protected final Object codecMember(final VarHandle handle, final String localName) {
72 final Object cached = handle.getAcquire(this);
73 return cached != null ? unmaskNull(cached) : loadMember(handle, context.getLeafChild(localName));
76 protected final Object codecMember(final VarHandle handle, final Class<? extends DataObject> bindingClass) {
77 final Object cached = handle.getAcquire(this);
78 return cached != null ? unmaskNull(cached) : loadMember(handle, context.getStreamChild(bindingClass));
81 protected final Object codecMember(final VarHandle handle, final CodecContextSupplier supplier) {
82 final Object cached = handle.getAcquire(this);
83 return cached != null ? unmaskNull(cached) : loadMember(handle, supplier.get());
86 protected final @NonNull Object codecMemberOrEmpty(final @Nullable Object value,
87 final @NonNull Class<? extends DataObject> bindingClass) {
88 return value != null ? value : emptyObject(bindingClass);
91 private @NonNull Object emptyObject(final @NonNull Class<? extends DataObject> bindingClass) {
92 final var childContext = context.getStreamChild(bindingClass);
93 if (childContext instanceof StructuralContainerCodecContext<?> structural) {
94 return structural.emptyObject();
96 throw new VerifyException("Unexpected context " + childContext);
99 protected final @NonNull Object codecKey(final VarHandle handle) {
100 final Object cached = handle.getAcquire(this);
101 return cached != null ? cached : loadKey(handle);
104 protected abstract int codecHashCode();
106 protected abstract boolean codecEquals(Object obj);
108 final @NonNull AbstractDataObjectCodecContext<T, ?> codecContext() {
112 final @NonNull DataContainerNode codecData() {
116 // Helper split out of codecMember to aid its inlining
117 private Object loadMember(final VarHandle handle, final CodecContext childCtx) {
118 final var child = data.childByArg(childCtx.getDomPathArgument());
120 // We do not want to use Optional.map() here because we do not want to invoke defaultObject() when we have
121 // normal value because defaultObject() may end up throwing an exception intentionally.
122 final Object obj = child != null ? childCtx.deserializeObject(child) : childCtx.defaultObject();
123 final Object witness = handle.compareAndExchangeRelease(this, null, maskNull(obj));
124 return witness == null ? obj : unmaskNull(witness);
127 // Helper split out of codecKey to aid its inlining
128 private @NonNull Object loadKey(final VarHandle handle) {
129 if (!(data instanceof MapEntryNode mapEntry)) {
130 throw new VerifyException("Unsupported value " + data);
132 if (!(context instanceof MapCodecContext<?, ?> listContext)) {
133 throw new VerifyException("Unexpected context " + context);
136 final Object obj = listContext.deserialize(mapEntry.name());
137 // key is known to be non-null, no need to mask it
138 final Object witness = handle.compareAndExchangeRelease(this, null, obj);
139 return witness == null ? obj : witness;
142 // Helper split out of hashCode() to aid its inlining
143 private int loadHashCode() {
144 final int result = codecHashCode();
145 final Object witness = CACHED_HASH_CODE.compareAndExchangeRelease(this, null, result);
146 return witness == null ? result : (Integer) witness;
149 private static @NonNull Object maskNull(final @Nullable Object unmasked) {
150 return unmasked == null ? NULL_VALUE : unmasked;
153 private static @Nullable Object unmaskNull(final Object masked) {
154 return masked == NULL_VALUE ? null : masked;