diff options
Diffstat (limited to 'java/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java')
| -rw-r--r-- | java/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java | 696 |
1 files changed, 696 insertions, 0 deletions
diff --git a/java/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java b/java/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java new file mode 100644 index 0000000..22760d3 --- /dev/null +++ b/java/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java @@ -0,0 +1,696 @@ +// 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; + +import java.util.AbstractList; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.List; + +/** + * {@code RepeatedFieldBuilder} implements a structure that a protocol + * message uses to hold a repeated field of other protocol messages. It supports + * the classical use case of adding immutable {@link Message}'s to the + * repeated field and is highly optimized around this (no extra memory + * allocations and sharing of immutable arrays). + * <br> + * It also supports the additional use case of adding a {@link Message.Builder} + * to the repeated 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. + * <br> + * 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 SingleFieldBuilder} and {@code RepeatedFieldBuilder} + * classes cache messages that were created so that messages only need to be + * created when some change occured in its builder or a builder for one of its + * descendants. + * + * @param <MType> the type of message for the field + * @param <BType> the type of builder for the field + * @param <IType> the common interface for the message and the builder + * + * @author jonp@google.com (Jon Perlow) + */ +public class RepeatedFieldBuilder + <MType extends GeneratedMessage, + BType extends GeneratedMessage.Builder, + IType extends MessageOrBuilder> + implements GeneratedMessage.BuilderParent { + + // Parent to send changes to. + private GeneratedMessage.BuilderParent parent; + + // List of messages. Never null. It may be immutable, in which case + // isMessagesListImmutable will be true. See note below. + private List<MType> messages; + + // Whether messages is an mutable array that can be modified. + private boolean isMessagesListMutable; + + // List of builders. May be null, in which case, no nested builders were + // created. If not null, entries represent the builder for that index. + private List<SingleFieldBuilder<MType, BType, IType>> builders; + + // Here are the invariants for messages and builders: + // 1. messages is never null and its count corresponds to the number of items + // in the repeated field. + // 2. If builders is non-null, messages and builders MUST always + // contain the same number of items. + // 3. Entries in either array can be null, but for any index, there MUST be + // either a Message in messages or a builder in builders. + // 4. If the builder at an index is non-null, the builder is + // authoritative. This is the case where a Builder was set on the index. + // Any message in the messages array MUST be ignored. + // t. If the builder at an index is null, the message in the messages + // list is authoritative. This is the case where a Message (not a Builder) + // was set directly for an index. + + // Indicates that we've built a message and so we are now obligated + // to dispatch dirty invalidations. See GeneratedMessage.BuilderListener. + private boolean isClean; + + // A view of this builder that exposes a List interface of messages. This is + // initialized on demand. This is fully backed by this object and all changes + // are reflected in it. Access to any item converts it to a message if it + // was a builder. + private MessageExternalList<MType, BType, IType> externalMessageList; + + // A view of this builder that exposes a List interface of builders. This is + // initialized on demand. This is fully backed by this object and all changes + // are reflected in it. Access to any item converts it to a builder if it + // was a message. + private BuilderExternalList<MType, BType, IType> externalBuilderList; + + // A view of this builder that exposes a List interface of the interface + // implemented by messages and builders. This is initialized on demand. This + // is fully backed by this object and all changes are reflected in it. + // Access to any item returns either a builder or message depending on + // what is most efficient. + private MessageOrBuilderExternalList<MType, BType, IType> + externalMessageOrBuilderList; + + /** + * Constructs a new builder with an empty list of messages. + * + * @param messages the current list of messages + * @param isMessagesListMutable Whether the messages list is mutable + * @param parent a listener to notify of changes + * @param isClean whether the builder is initially marked clean + */ + public RepeatedFieldBuilder( + List<MType> messages, + boolean isMessagesListMutable, + GeneratedMessage.BuilderParent parent, + boolean isClean) { + this.messages = messages; + this.isMessagesListMutable = isMessagesListMutable; + this.parent = parent; + this.isClean = isClean; + } + + public void dispose() { + // Null out parent so we stop sending it invalidations. + parent = null; + } + + /** + * Ensures that the list of messages is mutable so it can be updated. If it's + * immutable, a copy is made. + */ + private void ensureMutableMessageList() { + if (!isMessagesListMutable) { + messages = new ArrayList<MType>(messages); + isMessagesListMutable = true; + } + } + + /** + * Ensures that the list of builders is not null. If it's null, the list is + * created and initialized to be the same size as the messages list with + * null entries. + */ + private void ensureBuilders() { + if (this.builders == null) { + this.builders = + new ArrayList<SingleFieldBuilder<MType, BType, IType>>( + messages.size()); + for (int i = 0; i < messages.size(); i++) { + builders.add(null); + } + } + } + + /** + * Gets the count of items in the list. + * + * @return the count of items in the list. + */ + public int getCount() { + return messages.size(); + } + + /** + * Gets whether the list is empty. + * + * @return whether the list is empty + */ + public boolean isEmpty() { + return messages.isEmpty(); + } + + /** + * Get the message at the specified index. 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. + * + * @param index the index of the message to get + * @return the message for the specified index + */ + public MType getMessage(int index) { + return getMessage(index, false); + } + + /** + * Get the message at the specified index. 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. + * + * @param index the index of the message to get + * @param forBuild this is being called for build so we want to make sure + * we SingleFieldBuilder.build to send dirty invalidations + * @return the message for the specified index + */ + private MType getMessage(int index, boolean forBuild) { + if (this.builders == null) { + // We don't have any builders -- return the current Message. + // This is the case where no builder was created, so we MUST have a + // Message. + return messages.get(index); + } + + SingleFieldBuilder<MType, BType, IType> builder = builders.get(index); + if (builder == null) { + // We don't have a builder -- return the current message. + // This is the case where no builder was created for the entry at index, + // so we MUST have a message. + return messages.get(index); + + } else { + return forBuild ? builder.build() : builder.getMessage(); + } + } + + /** + * Gets a builder for the specified index. If no builder has been created for + * that index, a builder is created on demand by calling + * {@link Message#toBuilder}. + * + * @param index the index of the message to get + * @return The builder for that index + */ + public BType getBuilder(int index) { + ensureBuilders(); + SingleFieldBuilder<MType, BType, IType> builder = builders.get(index); + if (builder == null) { + MType message = messages.get(index); + builder = new SingleFieldBuilder<MType, BType, IType>( + message, this, isClean); + builders.set(index, builder); + } + return builder.getBuilder(); + } + + /** + * Gets the base class interface for the specified index. This may either be + * a builder or a message. It will return whatever is more efficient. + * + * @param index the index of the message to get + * @return the message or builder for the index as the base class interface + */ + @SuppressWarnings("unchecked") + public IType getMessageOrBuilder(int index) { + if (this.builders == null) { + // We don't have any builders -- return the current Message. + // This is the case where no builder was created, so we MUST have a + // Message. + return (IType) messages.get(index); + } + + SingleFieldBuilder<MType, BType, IType> builder = builders.get(index); + if (builder == null) { + // We don't have a builder -- return the current message. + // This is the case where no builder was created for the entry at index, + // so we MUST have a message. + return (IType) messages.get(index); + + } else { + return builder.getMessageOrBuilder(); + } + } + + /** + * Sets a message at the specified index replacing the existing item at + * that index. + * + * @param index the index to set. + * @param message the message to set + * @return the builder + */ + public RepeatedFieldBuilder<MType, BType, IType> setMessage( + int index, MType message) { + if (message == null) { + throw new NullPointerException(); + } + ensureMutableMessageList(); + messages.set(index, message); + if (builders != null) { + SingleFieldBuilder<MType, BType, IType> entry = + builders.set(index, null); + if (entry != null) { + entry.dispose(); + } + } + onChanged(); + incrementModCounts(); + return this; + } + + /** + * Appends the specified element to the end of this list. + * + * @param message the message to add + * @return the builder + */ + public RepeatedFieldBuilder<MType, BType, IType> addMessage( + MType message) { + if (message == null) { + throw new NullPointerException(); + } + ensureMutableMessageList(); + messages.add(message); + if (builders != null) { + builders.add(null); + } + onChanged(); + incrementModCounts(); + return this; + } + + /** + * Inserts the specified message at the specified position in this list. + * Shifts the element currently at that position (if any) and any subsequent + * elements to the right (adds one to their indices). + * + * @param index the index at which to insert the message + * @param message the message to add + * @return the builder + */ + public RepeatedFieldBuilder<MType, BType, IType> addMessage( + int index, MType message) { + if (message == null) { + throw new NullPointerException(); + } + ensureMutableMessageList(); + messages.add(index, message); + if (builders != null) { + builders.add(index, null); + } + onChanged(); + incrementModCounts(); + return this; + } + + /** + * Appends all of the messages in the specified collection to the end of + * this list, in the order that they are returned by the specified + * collection's iterator. + * + * @param values the messages to add + * @return the builder + */ + public RepeatedFieldBuilder<MType, BType, IType> addAllMessages( + Iterable<? extends MType> values) { + for (final MType value : values) { + if (value == null) { + throw new NullPointerException(); + } + } + if (values instanceof Collection) { + @SuppressWarnings("unchecked") final + Collection<MType> collection = (Collection<MType>) values; + if (collection.size() == 0) { + return this; + } + ensureMutableMessageList(); + for (MType value : values) { + addMessage(value); + } + } else { + ensureMutableMessageList(); + for (MType value : values) { + addMessage(value); + } + } + onChanged(); + incrementModCounts(); + return this; + } + + /** + * Appends a new builder to the end of this list and returns the builder. + * + * @param message the message to add which is the basis of the builder + * @return the new builder + */ + public BType addBuilder(MType message) { + ensureMutableMessageList(); + ensureBuilders(); + SingleFieldBuilder<MType, BType, IType> builder = + new SingleFieldBuilder<MType, BType, IType>( + message, this, isClean); + messages.add(null); + builders.add(builder); + onChanged(); + incrementModCounts(); + return builder.getBuilder(); + } + + /** + * Inserts a new builder at the specified position in this list. + * Shifts the element currently at that position (if any) and any subsequent + * elements to the right (adds one to their indices). + * + * @param index the index at which to insert the builder + * @param message the message to add which is the basis of the builder + * @return the builder + */ + public BType addBuilder(int index, MType message) { + ensureMutableMessageList(); + ensureBuilders(); + SingleFieldBuilder<MType, BType, IType> builder = + new SingleFieldBuilder<MType, BType, IType>( + message, this, isClean); + messages.add(index, null); + builders.add(index, builder); + onChanged(); + incrementModCounts(); + return builder.getBuilder(); + } + + /** + * Removes the element at the specified position in this list. Shifts any + * subsequent elements to the left (subtracts one from their indices). + * Returns the element that was removed from the list. + * + * @param index the index at which to remove the message + */ + public void remove(int index) { + ensureMutableMessageList(); + messages.remove(index); + if (builders != null) { + SingleFieldBuilder<MType, BType, IType> entry = + builders.remove(index); + if (entry != null) { + entry.dispose(); + } + } + onChanged(); + incrementModCounts(); + } + + /** + * Removes all of the elements from this list. + * The list will be empty after this call returns. + */ + public void clear() { + messages = Collections.emptyList(); + isMessagesListMutable = false; + if (builders != null) { + for (SingleFieldBuilder<MType, BType, IType> entry : + builders) { + if (entry != null) { + entry.dispose(); + } + } + builders = null; + } + onChanged(); + incrementModCounts(); + } + + /** + * Builds the list of messages from the builder and returns them. + * + * @return an immutable list of messages + */ + public List<MType> build() { + // Now that build has been called, we are required to dispatch + // invalidations. + isClean = true; + + if (!isMessagesListMutable && builders == null) { + // We still have an immutable list and we never created a builder. + return messages; + } + + boolean allMessagesInSync = true; + if (!isMessagesListMutable) { + // We still have an immutable list. Let's see if any of them are out + // of sync with their builders. + for (int i = 0; i < messages.size(); i++) { + Message message = messages.get(i); + SingleFieldBuilder<MType, BType, IType> builder = builders.get(i); + if (builder != null) { + if (builder.build() != message) { + allMessagesInSync = false; + break; + } + } + } + if (allMessagesInSync) { + // Immutable list is still in sync. + return messages; + } + } + + // Need to make sure messages is up to date + ensureMutableMessageList(); + for (int i = 0; i < messages.size(); i++) { + messages.set(i, getMessage(i, true)); + } + + // We're going to return our list as immutable so we mark that we can + // no longer update it. + messages = Collections.unmodifiableList(messages); + isMessagesListMutable = false; + return messages; + } + + /** + * Gets a view of the builder as a list of messages. The returned list is live + * and will reflect any changes to the underlying builder. + * + * @return the messages in the list + */ + public List<MType> getMessageList() { + if (externalMessageList == null) { + externalMessageList = + new MessageExternalList<MType, BType, IType>(this); + } + return externalMessageList; + } + + /** + * Gets a view of the builder as a list of builders. This returned list is + * live and will reflect any changes to the underlying builder. + * + * @return the builders in the list + */ + public List<BType> getBuilderList() { + if (externalBuilderList == null) { + externalBuilderList = + new BuilderExternalList<MType, BType, IType>(this); + } + return externalBuilderList; + } + + /** + * Gets a view of the builder as a list of MessageOrBuilders. This returned + * list is live and will reflect any changes to the underlying builder. + * + * @return the builders in the list + */ + public List<IType> getMessageOrBuilderList() { + if (externalMessageOrBuilderList == null) { + externalMessageOrBuilderList = + new MessageOrBuilderExternalList<MType, BType, IType>(this); + } + return externalMessageOrBuilderList; + } + + /** + * 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 (isClean && parent != null) { + parent.markDirty(); + + // Don't keep dispatching invalidations until build is called again. + isClean = false; + } + } + + //@Override (Java 1.6 override semantics, but we must support 1.5) + public void markDirty() { + onChanged(); + } + + /** + * Increments the mod counts so that an ConcurrentModificationException can + * be thrown if calling code tries to modify the builder while its iterating + * the list. + */ + private void incrementModCounts() { + if (externalMessageList != null) { + externalMessageList.incrementModCount(); + } + if (externalBuilderList != null) { + externalBuilderList.incrementModCount(); + } + if (externalMessageOrBuilderList != null) { + externalMessageOrBuilderList.incrementModCount(); + } + } + + /** + * Provides a live view of the builder as a list of messages. + * + * @param <MType> the type of message for the field + * @param <BType> the type of builder for the field + * @param <IType> the common interface for the message and the builder + */ + private static class MessageExternalList< + MType extends GeneratedMessage, + BType extends GeneratedMessage.Builder, + IType extends MessageOrBuilder> + extends AbstractList<MType> implements List<MType> { + + RepeatedFieldBuilder<MType, BType, IType> builder; + + MessageExternalList( + RepeatedFieldBuilder<MType, BType, IType> builder) { + this.builder = builder; + } + + public int size() { + return this.builder.getCount(); + } + + public MType get(int index) { + return builder.getMessage(index); + } + + void incrementModCount() { + modCount++; + } + } + + /** + * Provides a live view of the builder as a list of builders. + * + * @param <MType> the type of message for the field + * @param <BType> the type of builder for the field + * @param <IType> the common interface for the message and the builder + */ + private static class BuilderExternalList< + MType extends GeneratedMessage, + BType extends GeneratedMessage.Builder, + IType extends MessageOrBuilder> + extends AbstractList<BType> implements List<BType> { + + RepeatedFieldBuilder<MType, BType, IType> builder; + + BuilderExternalList( + RepeatedFieldBuilder<MType, BType, IType> builder) { + this.builder = builder; + } + + public int size() { + return this.builder.getCount(); + } + + public BType get(int index) { + return builder.getBuilder(index); + } + + void incrementModCount() { + modCount++; + } + } + + /** + * Provides a live view of the builder as a list of builders. + * + * @param <MType> the type of message for the field + * @param <BType> the type of builder for the field + * @param <IType> the common interface for the message and the builder + */ + private static class MessageOrBuilderExternalList< + MType extends GeneratedMessage, + BType extends GeneratedMessage.Builder, + IType extends MessageOrBuilder> + extends AbstractList<IType> implements List<IType> { + + RepeatedFieldBuilder<MType, BType, IType> builder; + + MessageOrBuilderExternalList( + RepeatedFieldBuilder<MType, BType, IType> builder) { + this.builder = builder; + } + + public int size() { + return this.builder.getCount(); + } + + public IType get(int index) { + return builder.getMessageOrBuilder(index); + } + + void incrementModCount() { + modCount++; + } + } +} |