Android example source code file (FileObserverTest.java)

This example Android source code file (FileObserverTest.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

access, android, attrib, close_nowrite, collect, collections, exception, fileobservertest, fileoutputstream, google, io, largetest, list, map, object, observer, override, string, test, util

The FileObserverTest.java Android example source code

/*
 * Copyright (C) 2006 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.os;

import com.google.android.collect.Lists;
import com.google.android.collect.Maps;

import android.os.FileObserver;
import android.test.AndroidTestCase;
import android.test.suitebuilder.annotation.LargeTest;
import android.util.Log;

import java.io.File;
import java.io.FileOutputStream;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class FileObserverTest extends AndroidTestCase {
    private Observer mObserver;
    private File mTestFile;

    private static class Observer extends FileObserver {
        public List<Map> events = Lists.newArrayList();
        public int totalEvents = 0;

        public Observer(String path) {
            super(path);
        }

        public void onEvent(int event, String path) {
            synchronized (this) {
                totalEvents++;
                Map<String, Object> map = Maps.newHashMap();

                map.put("event", event);
                map.put("path", path);

                events.add(map);

                this.notifyAll();
            }
        }
    }

    @Override
    protected void setUp() throws Exception {
        mTestFile = File.createTempFile(".file_observer_test", ".txt");
    }

    @Override
    protected void tearDown() throws Exception {
        if (mTestFile != null && mTestFile.exists()) {
            mTestFile.delete();
        }
    }

    @LargeTest
    public void testRun() throws Exception {
        // make file changes and wait for them
        assertTrue(mTestFile.exists());
        assertNotNull(mTestFile.getParent());

        mObserver = new Observer(mTestFile.getParent());
        mObserver.startWatching();

        FileOutputStream out = new FileOutputStream(mTestFile);
        try {
            out.write(0x20);
            waitForEvent(); // open
            waitForEvent(); // modify

            mTestFile.delete();
            waitForEvent(); // modify
            waitForEvent(); // delete

            mObserver.stopWatching();

            // Ensure that we have seen at least 3 events.
            assertTrue(mObserver.totalEvents > 3);
        } finally {
            out.close();
        }
    }

    private void waitForEvent() {
        synchronized (mObserver) {
            boolean done = false;
            while (!done) {
                try {
                    mObserver.wait(2000);
                    done = true;
                } catch (InterruptedException e) {
                }
            }

            Iterator<Map> it = mObserver.events.iterator();

            while (it.hasNext()) {
                Map map = it.next();
                Log.i("FileObserverTest", "event: " + getEventString((Integer)map.get("event")) + " path: " + map.get("path"));
            }

            mObserver.events.clear();
        }
    }

    private String getEventString(int event) {
        switch (event) {
            case  FileObserver.ACCESS:
                return "ACCESS";
            case FileObserver.MODIFY:
                return "MODIFY";
            case FileObserver.ATTRIB:
                return "ATTRIB";
            case FileObserver.CLOSE_WRITE:
                return "CLOSE_WRITE";
            case FileObserver.CLOSE_NOWRITE:
                return "CLOSE_NOWRITE";
            case FileObserver.OPEN:
                return "OPEN";
            case FileObserver.MOVED_FROM:
                return "MOVED_FROM";
            case FileObserver.MOVED_TO:
                return "MOVED_TO";
            case FileObserver.CREATE:
                return "CREATE";
            case FileObserver.DELETE:
                return "DELETE";
            case FileObserver.DELETE_SELF:
                return "DELETE_SELF";
            case FileObserver.MOVE_SELF:
                return "MOVE_SELF";
            default:
                return "UNKNOWN";
        }
    }
}