/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package benchmarks;
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import java.lang.ref.PhantomReference;
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import java.lang.ref.ReferenceQueue;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.concurrent.atomic.AtomicInteger;
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/**
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* Benchmark to evaluate the performance of References.
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*/
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public class ReferenceBenchmark {
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private Object object;
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// How fast can references can be allocated?
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public void timeAlloc(int reps) {
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ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
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for (int i = 0; i < reps; i++) {
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new PhantomReference(object, queue);
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}
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}
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// How fast can references can be allocated and manually enqueued?
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public void timeAllocAndEnqueue(int reps) {
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ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
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for (int i = 0; i < reps; i++) {
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(new PhantomReference<Object>(object, queue)).enqueue();
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}
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}
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// How fast can references can be allocated, enqueued, and polled?
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public void timeAllocEnqueueAndPoll(int reps) {
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ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
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for (int i = 0; i < reps; i++) {
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(new PhantomReference<Object>(object, queue)).enqueue();
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}
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for (int i = 0; i < reps; i++) {
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queue.poll();
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}
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}
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// How fast can references can be allocated, enqueued, and removed?
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public void timeAllocEnqueueAndRemove(int reps) {
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ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
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for (int i = 0; i < reps; i++) {
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(new PhantomReference<Object>(object, queue)).enqueue();
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}
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for (int i = 0; i < reps; i++) {
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try {
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queue.remove();
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} catch (InterruptedException ie) {
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i--;
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}
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}
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}
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// How fast can references can be implicitly allocated, enqueued, and
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// removed?
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public void timeAllocImplicitEnqueueAndRemove(int reps) {
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ReferenceQueue<Object> queue = new ReferenceQueue<Object>();
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List<Object> refs = new ArrayList<Object>();
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for (int i = 0; i < reps; i++) {
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refs.add(new PhantomReference<Object>(new Object(), queue));
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}
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Runtime.getRuntime().gc();
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for (int i = 0; i < reps; i++) {
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try {
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queue.remove();
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} catch (InterruptedException ie) {
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i--;
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}
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}
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}
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static private class FinalizableObject {
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AtomicInteger count;
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public FinalizableObject(AtomicInteger count) {
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this.count = count;
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}
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@Override
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protected void finalize() {
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count.incrementAndGet();
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}
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}
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// How fast does finalization run?
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public void timeFinalization(int reps) {
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// Allocate a bunch of finalizable objects.
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int n = reps;
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AtomicInteger count = new AtomicInteger(0);
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for (int i = 0; i < n; i++) {
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new FinalizableObject(count);
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}
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// Run GC so the objects will be collected for finalization.
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Runtime.getRuntime().gc();
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// Wait for finalization.
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Runtime.getRuntime().runFinalization();
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// Double check all the objects were finalized.
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int got = count.get();
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if (n != got) {
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throw new IllegalStateException(
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String.format("Only %i of %i objects finalized?", got, n));
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}
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}
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}
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