/src/com/google/protobuf/ExtensionRegistryLite.java
Java | 169 lines | 73 code | 16 blank | 80 comment | 7 complexity | 262cb688b28accec2fb653ad397a38b4 MD5 | raw file
- // Protocol Buffers - Google's data interchange format
- // Copyright 2008 Google Inc. All rights reserved.
- // http://code.google.com/p/protobuf/
- //
- // 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.Collections;
- import java.util.HashMap;
- import java.util.Map;
- /**
- * Equivalent to {@link ExtensionRegistry} but supports only "lite" types.
- * <p>
- * If all of your types are lite types, then you only need to use
- * {@code ExtensionRegistryLite}. Similarly, if all your types are regular
- * types, then you only need {@link ExtensionRegistry}. Typically it does not
- * make sense to mix the two, since if you have any regular types in your
- * program, you then require the full runtime and lose all the benefits of
- * the lite runtime, so you might as well make all your types be regular types.
- * However, in some cases (e.g. when depending on multiple third-patry libraries
- * where one uses lite types and one uses regular), you may find yourself
- * wanting to mix the two. In this case things get more complicated.
- * <p>
- * There are three factors to consider: Whether the type being extended is
- * lite, whether the embedded type (in the case of a message-typed extension)
- * is lite, and whether the extension itself is lite. Since all three are
- * declared in different files, they could all be different. Here are all
- * the combinations and which type of registry to use:
- * <pre>
- * Extended type Inner type Extension Use registry
- * =======================================================================
- * lite lite lite ExtensionRegistryLite
- * lite regular lite ExtensionRegistry
- * regular regular regular ExtensionRegistry
- * all other combinations not supported
- * </pre>
- * <p>
- * Note that just as regular types are not allowed to contain lite-type fields,
- * they are also not allowed to contain lite-type extensions. This is because
- * regular types must be fully accessible via reflection, which in turn means
- * that all the inner messages must also support reflection. On the other hand,
- * since regular types implement the entire lite interface, there is no problem
- * with embedding regular types inside lite types.
- *
- * @author kenton@google.com Kenton Varda
- */
- public class ExtensionRegistryLite {
- /** Construct a new, empty instance. */
- public static ExtensionRegistryLite newInstance() {
- return new ExtensionRegistryLite();
- }
- /** Get the unmodifiable singleton empty instance. */
- public static ExtensionRegistryLite getEmptyRegistry() {
- return EMPTY;
- }
- /** Returns an unmodifiable view of the registry. */
- public ExtensionRegistryLite getUnmodifiable() {
- return new ExtensionRegistryLite(this);
- }
- /**
- * Find an extension by containing type and field number.
- *
- * @return Information about the extension if found, or {@code null}
- * otherwise.
- */
- @SuppressWarnings("unchecked")
- public <ContainingType extends MessageLite>
- GeneratedMessageLite.GeneratedExtension<ContainingType, ?>
- findLiteExtensionByNumber(
- final ContainingType containingTypeDefaultInstance,
- final int fieldNumber) {
- return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>)
- extensionsByNumber.get(
- new ObjectIntPair(containingTypeDefaultInstance, fieldNumber));
- }
- /** Add an extension from a lite generated file to the registry. */
- public final void add(
- final GeneratedMessageLite.GeneratedExtension<?, ?> extension) {
- extensionsByNumber.put(
- new ObjectIntPair(extension.getContainingTypeDefaultInstance(),
- extension.getNumber()),
- extension);
- }
- // =================================================================
- // Private stuff.
- // Constructors are package-private so that ExtensionRegistry can subclass
- // this.
- ExtensionRegistryLite() {
- this.extensionsByNumber =
- new HashMap<ObjectIntPair,
- GeneratedMessageLite.GeneratedExtension<?, ?>>();
- }
- ExtensionRegistryLite(ExtensionRegistryLite other) {
- if (other == EMPTY) {
- this.extensionsByNumber = Collections.emptyMap();
- } else {
- this.extensionsByNumber =
- Collections.unmodifiableMap(other.extensionsByNumber);
- }
- }
- private final Map<ObjectIntPair,
- GeneratedMessageLite.GeneratedExtension<?, ?>>
- extensionsByNumber;
- private ExtensionRegistryLite(boolean empty) {
- this.extensionsByNumber = Collections.emptyMap();
- }
- private static final ExtensionRegistryLite EMPTY =
- new ExtensionRegistryLite(true);
- /** A (Object, int) pair, used as a map key. */
- private static final class ObjectIntPair {
- private final Object object;
- private final int number;
- ObjectIntPair(final Object object, final int number) {
- this.object = object;
- this.number = number;
- }
- @Override
- public int hashCode() {
- return System.identityHashCode(object) * ((1 << 16) - 1) + number;
- }
- @Override
- public boolean equals(final Object obj) {
- if (!(obj instanceof ObjectIntPair)) {
- return false;
- }
- final ObjectIntPair other = (ObjectIntPair)obj;
- return object == other.object && number == other.number;
- }
- }
- }