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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef JNI_CONSTANTS_H_included
#define JNI_CONSTANTS_H_included
#include <jni.h>
/**
* A cache to avoid calling FindClass at runtime.
*
* Class lookup is relatively expensive (2.5us on passion-eng at the time of writing), so we do
* all such lookups eagerly at VM startup. This means that code that never uses, say,
* java.util.zip.Deflater still has to pay for the lookup, but it means that on a device the cost
* is definitely paid during boot and amortized. A central cache also removes the temptation to
* dynamically call FindClass rather than add a small cache to each file that needs one. Another
* cost is that each class cached here requires a global reference, though in practice we save
* enough by not having a global reference for each file that uses a class such as java.lang.String
* which is used in several files.
*
* FindClass is still called in a couple of situations: when throwing exceptions, and in some of
* the serialization code. The former is clearly not a performance case, and we're currently
* assuming that neither is the latter.
*
* TODO: similar arguments hold for field and method IDs; we should cache them centrally too.
*/
struct JniConstants {
static void init(JNIEnv* env);
static jclass inet6AddressClass;
static jclass inetAddressClass;
static jclass inetSocketAddressClass;
static jclass stringClass;
};
#define NATIVE_METHOD(className, functionName, signature) \
{ #functionName, signature, reinterpret_cast<void*>(className ## _ ## functionName) }
#endif // JNI_CONSTANTS_H_included
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