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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
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-party 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 [email protected] Kenton Varda
*/
public class ExtensionRegistryLite {
// Set true to enable lazy parsing feature for MessageSet.
//
// TODO: Now we use a global flag to control whether enable lazy
// parsing feature for MessageSet, which may be too crude for some
// applications. Need to support this feature on smaller granularity.
private static volatile boolean eagerlyParseMessageSets = false;
// Visible for testing.
static final String EXTENSION_CLASS_NAME = "com.google.protobuf.Extension";
private static class ExtensionClassHolder {
static final Class INSTANCE = resolveExtensionClass();
static Class resolveExtensionClass() {
try {
return Class.forName(EXTENSION_CLASS_NAME);
} catch (ClassNotFoundException e) {
// See comment in ExtensionRegistryFactory on the potential expense of this.
return null;
}
}
}
public static boolean isEagerlyParseMessageSets() {
return eagerlyParseMessageSets;
}
public static void setEagerlyParseMessageSets(boolean isEagerlyParse) {
eagerlyParseMessageSets = isEagerlyParse;
}
/**
* Construct a new, empty instance.
*
*
This may be an {@code ExtensionRegistry} if the full (non-Lite) proto libraries are
* available.
*/
public static ExtensionRegistryLite newInstance() {
return Protobuf.assumeLiteRuntime
? new ExtensionRegistryLite()
: ExtensionRegistryFactory.create();
}
private static volatile ExtensionRegistryLite emptyRegistry;
/**
* Get the unmodifiable singleton empty instance of either ExtensionRegistryLite or {@code
* ExtensionRegistry} (if the full (non-Lite) proto libraries are available).
*/
public static ExtensionRegistryLite getEmptyRegistry() {
if (Protobuf.assumeLiteRuntime) {
return EMPTY_REGISTRY_LITE;
}
ExtensionRegistryLite result = emptyRegistry;
if (result == null) {
synchronized (ExtensionRegistryLite.class) {
result = emptyRegistry;
if (result == null) {
emptyRegistry = result = ExtensionRegistryFactory.createEmpty();
}
}
}
return result;
}
/** 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);
}
/**
* Add an extension from a lite generated file to the registry only if it is a non-lite extension
* i.e. {@link GeneratedMessageLite.GeneratedExtension}.
*/
public final void add(ExtensionLite extension) {
if (GeneratedMessageLite.GeneratedExtension.class.isAssignableFrom(extension.getClass())) {
add((GeneratedMessageLite.GeneratedExtension) extension);
}
if (!Protobuf.assumeLiteRuntime && ExtensionRegistryFactory.isFullRegistry(this)) {
try {
this.getClass().getMethod("add", ExtensionClassHolder.INSTANCE).invoke(this, extension);
} catch (Exception e) {
throw new IllegalArgumentException(
String.format("Could not invoke ExtensionRegistry#add for %s", extension), e);
}
}
}
// =================================================================
// Private stuff.
// Constructors are package-private so that ExtensionRegistry can subclass
// this.
ExtensionRegistryLite() {
this.extensionsByNumber =
new HashMap>();
}
static final ExtensionRegistryLite EMPTY_REGISTRY_LITE = new ExtensionRegistryLite(true);
ExtensionRegistryLite(ExtensionRegistryLite other) {
if (other == EMPTY_REGISTRY_LITE) {
this.extensionsByNumber = Collections.emptyMap();
} else {
this.extensionsByNumber = Collections.unmodifiableMap(other.extensionsByNumber);
}
}
private final Map>
extensionsByNumber;
ExtensionRegistryLite(boolean empty) {
this.extensionsByNumber = Collections.emptyMap();
}
/** 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;
}
}
}