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Android example source code file (HeapTest.java)

This example Android source code file (HeapTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, finalizableobject, linkedlist, mediumtest, num_refs, object, outofmemoryerror, phantomreference, referencequeue, run_flaky, runtimeexception, sixteen_mb, softreference, test, util, utilities, utils, weakreference

The HeapTest.java Android example source code

/*
 * Copyright (C) 2007 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.
 */

package android.core;

import android.test.suitebuilder.annotation.LargeTest;
import android.test.suitebuilder.annotation.MediumTest;
import android.test.suitebuilder.annotation.SmallTest;
import android.util.Log;
import android.test.suitebuilder.annotation.Suppress;
import dalvik.system.VMRuntime;
import junit.framework.TestCase;

import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
import java.util.LinkedList;
import java.util.Random;


public class HeapTest extends TestCase {

    private static final String TAG = "HeapTest";

    /**
     * Returns a WeakReference to an object that has no
     * other references.  This is done in a separate method
     * to ensure that the Object's address isn't sitting in
     * a stale local register.
     */
    private WeakReference<Object> newRef() {
        return new WeakReference<Object>(new Object());
    }

    /**
     * Allocates the specified number of bytes. This is done in a separate method
     * to ensure that the Object's address isn't sitting in a stale local register.
     */
    private void allocateMemory(int size) {
        byte[] b = new byte[size];
    }

    @MediumTest
    public void testMinimumHeapSize() throws Exception {
        VMRuntime r = VMRuntime.getRuntime();
        final boolean RUN_FLAKY = false;

        long origSize = r.getMinimumHeapSize();
        if (RUN_FLAKY) {
            /* Check that the default value is zero.  This will break if anyone
             * in this process sets the minimum heap size to a positive value
             * before calling this test.
             */
            assertTrue(origSize == 0);
        }

        long size = 4 * 1024 * 1024;
        long oldSize = r.setMinimumHeapSize(size);
        assertTrue(oldSize == origSize);

        long newSize = r.getMinimumHeapSize();
        /* This will fail if the maximum heap size (-Xmx) is smaller than 4MB.
         */
        assertTrue(newSize == size);

        /* Make sure that getting the size doesn't change anything.
         */
        newSize = r.getMinimumHeapSize();
        assertTrue(newSize == size);

        /* This test is flaky; if the heap is already large and fragmented,
         * it can fail.  It can also fail if another thread causes a GC
         * at the wrong time.
         */
        if (RUN_FLAKY) {
            /* Increase the minimum size, allocate a big object, and make sure that
             * a GC didn't happen.
             */
            WeakReference ref = newRef();
            assertNotNull(ref.get());

            r.setMinimumHeapSize(8 * 1024 * 1024);
            allocateMemory(4 * 1024 * 1024);

            /* If a GC happened, this reference will be null.
             */
            assertNotNull(ref.get());
        }

        /* Restore the original setting.
         */
        r.setMinimumHeapSize(origSize);
        newSize = r.getMinimumHeapSize();
        assertTrue(newSize == origSize);

        /* Clean up any large stuff we've allocated,
         * and re-establish the normal utilization ratio.
         */
        Runtime.getRuntime().gc();
    }

    private static void makeRefs(Object objects[], SoftReference<Object> refs[]) {
        for (int i = 0; i < objects.length; i++) {
            objects[i] = (Object) new byte[8 * 1024];
            refs[i] = new SoftReference<Object>(objects[i]);
        }
    }

    private static <T> int checkRefs(SoftReference refs[], int last) {
        int i;
        int numCleared = 0;
        for (i = 0; i < refs.length; i++) {
            Object o = refs[i].get();
            if (o == null) {
                numCleared++;
            }
        }
        if (numCleared != last) {
            Log.i(TAG, "****** " + numCleared + "/" + i + " cleared ******");
        }
        return numCleared;
    }

    private static void clearRefs(Object objects[], int skip) {
        for (int i = 0; i < objects.length; i += skip) {
            objects[i] = null;
        }
    }

    private static void clearRefs(Object objects[]) {
        clearRefs(objects, 1);
    }

    private static <T> void checkRefs(T objects[], SoftReference refs[]) {
        boolean ok = true;

        for (int i = 0; i < objects.length; i++) {
            if (refs[i].get() != objects[i]) {
                ok = false;
            }
        }
        if (!ok) {
            throw new RuntimeException("Test failed: soft refs not cleared");
        }
    }

    @MediumTest
    public void testGcSoftRefs() throws Exception {
        final int NUM_REFS = 128;

        Object objects[] = new Object[NUM_REFS];
        SoftReference<Object> refs[] = new SoftReference[objects.length];

        /* Create a bunch of objects and a parallel array
         * of SoftReferences.
         */
        makeRefs(objects, refs);
        Runtime.getRuntime().gc();

        /* Let go of some of the hard references to the objects so that
         * the references can be cleared.
         */
        clearRefs(objects, 3);

        /* Collect all softly-reachable objects.
         */
        VMRuntime.getRuntime().gcSoftReferences();
        Runtime.getRuntime().runFinalization();

        /* Make sure that the objects were collected.
         */
        checkRefs(objects, refs);

        /* Remove more hard references and re-check.
         */
        clearRefs(objects, 2);
        VMRuntime.getRuntime().gcSoftReferences();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs);

        /* Remove the rest of the references and re-check.
         */
        /* Remove more hard references and re-check.
         */
        clearRefs(objects);
        VMRuntime.getRuntime().gcSoftReferences();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs);
    }

    public void xxtestSoftRefPartialClean() throws Exception {
        final int NUM_REFS = 128;

        Object objects[] = new Object[NUM_REFS];
        SoftReference<Object> refs[] = new SoftReference[objects.length];

        /* Create a bunch of objects and a parallel array
        * of SoftReferences.
        */
        makeRefs(objects, refs);
        Runtime.getRuntime().gc();

        /* Let go of the hard references to the objects so that
        * the references can be cleared.
        */
        clearRefs(objects);

        /* Start creating a bunch of temporary and permanent objects
        * to drive GC.
        */
        final int NUM_OBJECTS = 64 * 1024;
        Object junk[] = new Object[NUM_OBJECTS];
        Random random = new Random();

        int i = 0;
        int mod = 0;
        int totalSize = 0;
        int cleared = -1;
        while (i < junk.length && totalSize < 8 * 1024 * 1024) {
            int r = random.nextInt(64 * 1024) + 128;
            Object o = (Object) new byte[r];
            if (++mod % 16 == 0) {
                junk[i++] = o;
                totalSize += r * 4;
            }
            cleared = checkRefs(refs, cleared);
        }
    }

    private static void makeRefs(Object objects[], WeakReference<Object> refs[]) {
        for (int i = 0; i < objects.length; i++) {
            objects[i] = new Object();
            refs[i] = new WeakReference<Object>(objects[i]);
        }
    }

    private static <T> void checkRefs(T objects[], WeakReference refs[]) {
        boolean ok = true;

        for (int i = 0; i < objects.length; i++) {
            if (refs[i].get() != objects[i]) {
                ok = false;
            }
        }
        if (!ok) {
            throw new RuntimeException("Test failed: " +
                    "weak refs not cleared");
        }
    }

    @MediumTest
    public void testWeakRefs() throws Exception {
        final int NUM_REFS = 16;

        Object objects[] = new Object[NUM_REFS];
        WeakReference<Object> refs[] = new WeakReference[objects.length];

        /* Create a bunch of objects and a parallel array
        * of WeakReferences.
        */
        makeRefs(objects, refs);
        Runtime.getRuntime().gc();
        checkRefs(objects, refs);

        /* Clear out every other strong reference.
        */
        for (int i = 0; i < objects.length; i += 2) {
            objects[i] = null;
        }
        Runtime.getRuntime().gc();
        checkRefs(objects, refs);

        /* Clear out the rest of them.
        */
        for (int i = 0; i < objects.length; i++) {
            objects[i] = null;
        }
        Runtime.getRuntime().gc();
        checkRefs(objects, refs);
    }

    private static void makeRefs(Object objects[], PhantomReference<Object> refs[],
            ReferenceQueue<Object> queue) {
        for (int i = 0; i < objects.length; i++) {
            objects[i] = new Object();
            refs[i] = new PhantomReference<Object>(objects[i], queue);
        }
    }

    static <T> void checkRefs(T objects[], PhantomReference refs[],
            ReferenceQueue<T> queue) {
        boolean ok = true;

        /* Make sure that the reference that should be on
        * the queue are marked as enqueued.  Once we
        * pull them off the queue, they will no longer
        * be marked as enqueued.
        */
        for (int i = 0; i < objects.length; i++) {
            if (objects[i] == null && refs[i] != null) {
                if (!refs[i].isEnqueued()) {
                    ok = false;
                }
            }
        }
        if (!ok) {
            throw new RuntimeException("Test failed: " +
                    "phantom refs not marked as enqueued");
        }

        /* Make sure that all of the references on the queue
        * are supposed to be there.
        */
        PhantomReference<T> ref;
        while ((ref = (PhantomReference<T>) queue.poll()) != null) {
            /* Find the list index that corresponds to this reference.
            */
            int i;
            for (i = 0; i < objects.length; i++) {
                if (refs[i] == ref) {
                    break;
                }
            }
            if (i == objects.length) {
                throw new RuntimeException("Test failed: " +
                        "unexpected ref on queue");
            }
            if (objects[i] != null) {
                throw new RuntimeException("Test failed: " +
                        "reference enqueued for strongly-reachable " +
                        "object");
            }
            refs[i] = null;

            /* TODO: clear doesn't do much, since we're losing the
            * strong ref to the ref object anyway.  move the ref
            * into another list.
            */
            ref.clear();
        }

        /* We've visited all of the enqueued references.
        * Make sure that there aren't any other references
        * that should have been enqueued.
        *
        * NOTE: there is a race condition here;  this assumes
        * that the VM has serviced all outstanding reference
        * enqueue() calls.
        */
        for (int i = 0; i < objects.length; i++) {
            if (objects[i] == null && refs[i] != null) {
//                System.out.println("HeapTest/PhantomRefs: refs[" + i +
//                        "] should be enqueued");
                ok = false;
            }
        }
        if (!ok) {
            throw new RuntimeException("Test failed: " +
                    "phantom refs not enqueued");
        }
    }

    @MediumTest
    public void testPhantomRefs() throws Exception {
        final int NUM_REFS = 16;

        Object objects[] = new Object[NUM_REFS];
        PhantomReference<Object> refs[] = new PhantomReference[objects.length];
        ReferenceQueue<Object> queue = new ReferenceQueue();

        /* Create a bunch of objects and a parallel array
        * of PhantomReferences.
        */
        makeRefs(objects, refs, queue);
        Runtime.getRuntime().gc();
        checkRefs(objects, refs, queue);

        /* Clear out every other strong reference.
        */
        for (int i = 0; i < objects.length; i += 2) {
            objects[i] = null;
        }
        // System.out.println("HeapTest/PhantomRefs: cleared evens");
        Runtime.getRuntime().gc();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs, queue);

        /* Clear out the rest of them.
        */
        for (int i = 0; i < objects.length; i++) {
            objects[i] = null;
        }
        // System.out.println("HeapTest/PhantomRefs: cleared all");
        Runtime.getRuntime().gc();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs, queue);
    }

    private static int sNumFinalized = 0;
    private static final Object sLock = new Object();

    private static class FinalizableObject {
        protected void finalize() {
            // System.out.println("gc from finalize()");
            Runtime.getRuntime().gc();
            synchronized (sLock) {
                sNumFinalized++;
            }
        }
    }

    private static void makeRefs(FinalizableObject objects[],
            WeakReference<FinalizableObject> refs[]) {
        for (int i = 0; i < objects.length; i++) {
            objects[i] = new FinalizableObject();
            refs[i] = new WeakReference<FinalizableObject>(objects[i]);
        }
    }

    @LargeTest
    public void testWeakRefsAndFinalizers() throws Exception {
        final int NUM_REFS = 16;

        FinalizableObject objects[] = new FinalizableObject[NUM_REFS];
        WeakReference<FinalizableObject> refs[] = new WeakReference[objects.length];
        int numCleared;

        /* Create a bunch of objects and a parallel array
        * of WeakReferences.
        */
        makeRefs(objects, refs);
        Runtime.getRuntime().gc();
        checkRefs(objects, refs);

        /* Clear out every other strong reference.
        */
        sNumFinalized = 0;
        numCleared = 0;
        for (int i = 0; i < objects.length; i += 2) {
            objects[i] = null;
            numCleared++;
        }
        // System.out.println("HeapTest/WeakRefsAndFinalizers: cleared evens");
        Runtime.getRuntime().gc();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs);
        if (sNumFinalized != numCleared) {
            throw new RuntimeException("Test failed: " +
                    "expected " + numCleared + " finalizations, saw " +
                    sNumFinalized);
        }

        /* Clear out the rest of them.
        */
        sNumFinalized = 0;
        numCleared = 0;
        for (int i = 0; i < objects.length; i++) {
            if (objects[i] != null) {
                objects[i] = null;
                numCleared++;
            }
        }
        // System.out.println("HeapTest/WeakRefsAndFinalizers: cleared all");
        Runtime.getRuntime().gc();
        Runtime.getRuntime().runFinalization();
        checkRefs(objects, refs);
        if (sNumFinalized != numCleared) {
            throw new RuntimeException("Test failed: " +
                    "expected " + numCleared + " finalizations, saw " +
                    sNumFinalized);
        }
    }

    // TODO: flaky test
    //@MediumTest
    public void testOomeLarge() throws Exception {
        /* Just shy of the typical max heap size so that it will actually
         * try to allocate it instead of short-circuiting.
         */
        final int SIXTEEN_MB = (16 * 1024 * 1024 - 32);

        Boolean sawEx = false;
        byte a[];

        try {
            a = new byte[SIXTEEN_MB];
        } catch (OutOfMemoryError oom) {
            //Log.i(TAG, "HeapTest/OomeLarge caught " + oom);
            sawEx = true;
        }

        if (!sawEx) {
            throw new RuntimeException("Test failed: " +
                    "OutOfMemoryError not thrown");
        }
    }

    //See bug 1308253 for reasons.
    @Suppress
    public void disableTestOomeSmall() throws Exception {
        final int SIXTEEN_MB = (16 * 1024 * 1024);
        final int LINK_SIZE = 6 * 4; // estimated size of a LinkedList's node

        Boolean sawEx = false;

        LinkedList<Object> list = new LinkedList();

        /* Allocate progressively smaller objects to fill up the entire heap.
         */
        int objSize = 1 * 1024 * 1024;
        while (objSize >= LINK_SIZE) {
            try {
                for (int i = 0; i < SIXTEEN_MB / objSize; i++) {
                    list.add((Object)new byte[objSize]);
                }
            } catch (OutOfMemoryError oom) {
                sawEx = true;
            }

            if (!sawEx) {
                throw new RuntimeException("Test failed: " +
                        "OutOfMemoryError not thrown while filling heap");
            }
            sawEx = false;

            objSize = (objSize * 4) / 5;
        }
    }

    // TODO: flaky test
    //@SmallTest
    public void testExternalOomeLarge() {
        /* Just shy of the typical max heap size so that it will actually
         * try to allocate it instead of short-circuiting.
         */
        final int HUGE_SIZE = (16 * 1024 * 1024 - 32);

        assertFalse(VMRuntime.getRuntime().trackExternalAllocation(HUGE_SIZE));
    }

    /**
     * "Allocates" external memory in progressively smaller chunks until there's
     * only roughly 16 bytes left.
     *
     * @return the number of bytes allocated
     */
    private long allocateMaxExternal() {
        final VMRuntime runtime = VMRuntime.getRuntime();
        final int SIXTEEN_MB = (16 * 1024 * 1024);
        final int MIN_SIZE = 16;
        long totalAllocated = 0;
        boolean success;

        success = false;
        try {
            /* "Allocate" progressively smaller chunks to "fill up" the entire heap.
             */
            int objSize = 1 * 1024 * 1024;
            while (objSize >= MIN_SIZE) {
                boolean sawFailure = false;
                for (int i = 0; i < SIXTEEN_MB / objSize; i++) {
                    if (runtime.trackExternalAllocation(objSize)) {
                        totalAllocated += objSize;
                    } else {
                        sawFailure = true;
                        break;
                    }
                }

                if (!sawFailure) {
                    throw new RuntimeException("Test failed: " +
                            "no failure while filling heap");
                }

                objSize = (objSize * 4) / 5;
            }
            success = true;
        } finally {
            if (!success) {
                runtime.trackExternalFree(totalAllocated);
                totalAllocated = 0;
            }
        }
        return totalAllocated;
    }

    public void xxtest00ExternalOomeSmall() {
        VMRuntime.getRuntime().trackExternalFree(allocateMaxExternal());
    }

    /**
     * Allocates as much external memory as possible, then allocates from the heap
     * until an OOME is caught.
     *
     * It's nice to run this test while the real heap is small, hence the '00' in its
     * name to force it to run before testOomeSmall().
     */
    public void xxtest00CombinedOomeSmall() {
        long totalAllocated = 0;
        boolean sawEx = false;
        try {
            totalAllocated = allocateMaxExternal();
            LinkedList<Object> list = new LinkedList();
            try {
                while (true) {
                    list.add((Object)new byte[8192]);
                }
                /*NOTREACHED*/
            } catch (OutOfMemoryError oom) {
                sawEx = true;
            }
        } finally {
            VMRuntime.getRuntime().trackExternalFree(totalAllocated);
        }
        assertTrue(sawEx);
    }

    //TODO: test external alloc debugging/inspection
}

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