Android example source code file (DatabaseLockTest.java)

This example Android source code file (DatabaseLockTest.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, app, atomicinteger, averagetime, content, databasefairnessthread, databaselatencythread, databaselocklatency, file, interruptedexception, io, max_allowed_latency_time, num_iterations, override, sleep_time, sqlitedatabase, suppress, test, thread, util

The DatabaseLockTest.java Android example source code

/*
 * Copyright (C) 2009 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.database;

import android.app.Activity;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.test.suitebuilder.annotation.LargeTest;
import android.test.suitebuilder.annotation.Suppress;
import android.util.Log;
import java.io.File;
import java.util.concurrent.atomic.AtomicInteger;
import android.test.AndroidTestCase;

import junit.framework.TestCase;

/* 
 * This is a series of unit tests for database locks.
 *
 * Suppress these tests for now, since they have has inconsistent results.
 * This should be turned into a performance tracking test.
 */
@Suppress
public class DatabaseLockTest extends AndroidTestCase {

    private static final int NUM_ITERATIONS = 100;
    private static final int SLEEP_TIME = 30;
    private static final int MAX_ALLOWED_LATENCY_TIME = 30;
    private SQLiteDatabase mDatabase;
    private File mDatabaseFile;
    private AtomicInteger mCounter = new AtomicInteger();

    @Override
    protected void setUp() throws Exception {
        super.setUp();
        File parentDir = getContext().getFilesDir();
        mDatabaseFile = new File(parentDir, "database_test.db");
        
        if (mDatabaseFile.exists()) {
            mDatabaseFile.delete();
        }
        mDatabase = SQLiteDatabase.openOrCreateDatabase(mDatabaseFile.getPath(), null);
        assertNotNull(mDatabase);
    }

    @Override
    protected void tearDown() throws Exception {
        mDatabase.close();
        mDatabaseFile.delete();
        super.tearDown();
    }

    /*
     * testLockFairness() tests the fairness of prioritizing multiple threads 
     * attempting to access a database concurrently.
     * This test is intended to verify that, when two threads are accessing the
     * same database at the same time with the same prioritization, neither thread 
     * is locked out and prevented from accessing the database.
     */
    @Suppress
    public void testLockFairness() {
        startDatabaseFairnessThread();
        int previous = 0;
        for (int i = 0; i < NUM_ITERATIONS; i++) { 
            mDatabase.beginTransaction();
            int val = mCounter.get();
            if (i == 0) {
                previous = val - i;
            }
            assertTrue(previous == (val - i));
            try {
                Thread.currentThread().sleep(SLEEP_TIME); 
            } catch (InterruptedException e) {
                // ignore
            }
            mDatabase.endTransaction();
        }
    }
    
    /*
     * This function is to create the second thread for testLockFairness() test.
     */
    private void startDatabaseFairnessThread() {
        Thread thread = new DatabaseFairnessThread();
        thread.start();
    }

    private class DatabaseFairnessThread extends Thread {
        @Override
        public void run() {
            for (int i = 0; i < NUM_ITERATIONS; i++) {
                mDatabase.beginTransaction();
                int val = mCounter.incrementAndGet();
                try {
                    Thread.currentThread().sleep(SLEEP_TIME);
                } catch (InterruptedException e) {
                    // ignore
                }
                mDatabase.endTransaction();
            }
        }
    }    
    
    /*
     * testLockLatency() tests the latency of database locks.
     * This test is intended to verify that, even when two threads are accessing
     * the same database, the locking/unlocking of the database is done within an
     * appropriate amount of time (MAX_ALLOWED_LATENCY_TIME).
     */
    @Suppress
    public void testLockLatency() {
        startDatabaseLatencyThread();
        int previous = 0;
        long sumTime = 0;
        long maxTime = 0;
        for (int i = 0; i < NUM_ITERATIONS; i++) { 
            long startTime = System.currentTimeMillis();
            mDatabase.beginTransaction();
            long endTime = System.currentTimeMillis();
            long elapsedTime = endTime - startTime;
            if (maxTime < elapsedTime) {
                maxTime = elapsedTime;
            }
            sumTime += elapsedTime;
            try {
                Thread.currentThread().sleep(SLEEP_TIME); 
            } catch (InterruptedException e) {
                // ignore
            }   
            mDatabase.endTransaction();
        }
        long averageTime = sumTime/NUM_ITERATIONS;
        Log.i("DatabaseLockLatency", "AverageTime: " + averageTime);
        Log.i("DatabaseLockLatency", "MaxTime: " + maxTime);
        assertTrue( (averageTime - SLEEP_TIME) <= MAX_ALLOWED_LATENCY_TIME);
    }
    
    /*
     * This function is to create the second thread for testLockLatency() test.
     */
    private void startDatabaseLatencyThread() {
        Thread thread = new DatabaseLatencyThread();
        thread.start();
    }

    private class DatabaseLatencyThread extends Thread {
        @Override
        public void run() {
            for (int i = 0; i < NUM_ITERATIONS; i++) 
            {
                mDatabase.beginTransaction();
                try {
                    Thread.currentThread().sleep(SLEEP_TIME);
                } catch (InterruptedException e) {
                    // ignore
                } 
                mDatabase.endTransaction();
            }
        }
    }        
}