From d64a2d9941c36a7bc2a7959ea10ab8363192ac14 Mon Sep 17 00:00:00 2001 From: Adam Cozzette Date: Wed, 29 Jun 2016 15:23:27 -0700 Subject: Integrated internal changes from Google This includes all internal changes from around May 20 to now. --- .../com/google/protobuf/SingleFieldBuilderV3.java | 241 +++++++++++++++++++++ 1 file changed, 241 insertions(+) create mode 100644 java/core/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java (limited to 'java/core/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java') diff --git a/java/core/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java new file mode 100644 index 00000000..fb1f76a7 --- /dev/null +++ b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilderV3.java @@ -0,0 +1,241 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +package com.google.protobuf; + +/** + * {@code SingleFieldBuilderV3} implements a structure that a protocol + * message uses to hold a single field of another protocol message. It supports + * the classical use case of setting an immutable {@link Message} as the value + * of the field and is highly optimized around this. + *
+ * It also supports the additional use case of setting a {@link Message.Builder} + * as the field and deferring conversion of that {@code Builder} + * to an immutable {@code Message}. In this way, it's possible to maintain + * a tree of {@code Builder}'s that acts as a fully read/write data + * structure. + *
+ * Logically, one can think of a tree of builders as converting the entire tree + * to messages when build is called on the root or when any method is called + * that desires a Message instead of a Builder. In terms of the implementation, + * the {@code SingleFieldBuilderV3} and {@code RepeatedFieldBuilderV3} + * classes cache messages that were created so that messages only need to be + * created when some change occurred in its builder or a builder for one of its + * descendants. + * + * @param the type of message for the field + * @param the type of builder for the field + * @param the common interface for the message and the builder + * + * @author jonp@google.com (Jon Perlow) + */ +public class SingleFieldBuilderV3 + + implements AbstractMessage.BuilderParent { + + // Parent to send changes to. + private AbstractMessage.BuilderParent parent; + + // Invariant: one of builder or message fields must be non-null. + + // If set, this is the case where we are backed by a builder. In this case, + // message field represents a cached message for the builder (or null if + // there is no cached message). + private BType builder; + + // If builder is non-null, this represents a cached message from the builder. + // If builder is null, this is the authoritative message for the field. + private MType message; + + // Indicates that we've built a message and so we are now obligated + // to dispatch dirty invalidations. See AbstractMessage.BuilderListener. + private boolean isClean; + + public SingleFieldBuilderV3( + MType message, + AbstractMessage.BuilderParent parent, + boolean isClean) { + if (message == null) { + throw new NullPointerException(); + } + this.message = message; + this.parent = parent; + this.isClean = isClean; + } + + public void dispose() { + // Null out parent so we stop sending it invalidations. + parent = null; + } + + /** + * Get the message for the field. If the message is currently stored + * as a {@code Builder}, it is converted to a {@code Message} by + * calling {@link Message.Builder#buildPartial} on it. If no message has + * been set, returns the default instance of the message. + * + * @return the message for the field + */ + @SuppressWarnings("unchecked") + public MType getMessage() { + if (message == null) { + // If message is null, the invariant is that we must be have a builder. + message = (MType) builder.buildPartial(); + } + return message; + } + + /** + * Builds the message and returns it. + * + * @return the message + */ + public MType build() { + // Now that build has been called, we are required to dispatch + // invalidations. + isClean = true; + return getMessage(); + } + + /** + * Gets a builder for the field. If no builder has been created yet, a + * builder is created on demand by calling {@link Message#toBuilder}. + * + * @return The builder for the field + */ + @SuppressWarnings("unchecked") + public BType getBuilder() { + if (builder == null) { + // builder.mergeFrom() on a fresh builder + // does not create any sub-objects with independent clean/dirty states, + // therefore setting the builder itself to clean without actually calling + // build() cannot break any invariants. + builder = (BType) message.newBuilderForType(this); + builder.mergeFrom(message); // no-op if message is the default message + builder.markClean(); + } + return builder; + } + + /** + * Gets the base class interface for the field. This may either be a builder + * or a message. It will return whatever is more efficient. + * + * @return the message or builder for the field as the base class interface + */ + @SuppressWarnings("unchecked") + public IType getMessageOrBuilder() { + if (builder != null) { + return (IType) builder; + } else { + return (IType) message; + } + } + + /** + * Sets a message for the field replacing any existing value. + * + * @param message the message to set + * @return the builder + */ + public SingleFieldBuilderV3 setMessage( + MType message) { + if (message == null) { + throw new NullPointerException(); + } + this.message = message; + if (builder != null) { + builder.dispose(); + builder = null; + } + onChanged(); + return this; + } + + /** + * Merges the field from another field. + * + * @param value the value to merge from + * @return the builder + */ + public SingleFieldBuilderV3 mergeFrom( + MType value) { + if (builder == null && message == message.getDefaultInstanceForType()) { + message = value; + } else { + getBuilder().mergeFrom(value); + } + onChanged(); + return this; + } + + /** + * Clears the value of the field. + * + * @return the builder + */ + @SuppressWarnings("unchecked") + public SingleFieldBuilderV3 clear() { + message = (MType) (message != null ? + message.getDefaultInstanceForType() : + builder.getDefaultInstanceForType()); + if (builder != null) { + builder.dispose(); + builder = null; + } + onChanged(); + return this; + } + + /** + * Called when a the builder or one of its nested children has changed + * and any parent should be notified of its invalidation. + */ + private void onChanged() { + // If builder is null, this is the case where onChanged is being called + // from setMessage or clear. + if (builder != null) { + message = null; + } + if (isClean && parent != null) { + parent.markDirty(); + + // Don't keep dispatching invalidations until build is called again. + isClean = false; + } + } + + @Override + public void markDirty() { + onChanged(); + } +} -- cgit v1.2.3