// 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. *

* 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. *

* 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: *

 *   Extended type     Inner type    Extension         Use registry
 *   =======================================================================
 *   lite              lite          lite              ExtensionRegistryLite
 *   lite              regular       lite              ExtensionRegistry
 *   regular           regular       regular           ExtensionRegistry
 *   all other combinations                            not supported
 * 
*

* 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 GeneratedMessageLite.GeneratedExtension findLiteExtensionByNumber( final ContainingType containingTypeDefaultInstance, final int fieldNumber) { return (GeneratedMessageLite.GeneratedExtension) 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>(); } ExtensionRegistryLite(ExtensionRegistryLite other) { if (other == EMPTY) { this.extensionsByNumber = Collections.emptyMap(); } else { this.extensionsByNumber = Collections.unmodifiableMap(other.extensionsByNumber); } } private final Map> 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; } } }