Commons IO example source code file (FileAlterationMonitorTestCase.java)

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

Java - Commons IO tags/keywords

delete, exception, file, file, filealterationmonitor, filealterationmonitor, filealterationmonitortestcase, filealterationobserver, filealterationobserver, illegalstateexception, interval, io, observers, observers, threw, util

The Commons IO FileAlterationMonitorTestCase.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.io.monitor;

import java.io.File;
import java.util.Collection;
import java.util.Iterator;

/**
 * {@link FileAlterationMonitor} Test Case.
 */
public class FileAlterationMonitorTestCase extends AbstractMonitorTestCase {

    /**
     * Construct a new test case.
     *
     * @param name The name of the test
     */
    public FileAlterationMonitorTestCase(String name) {
        super(name);
        testDirName = "test-monitor";
    }

    @Override
    protected void setUp() throws Exception {
        listener = new CollectionFileListener(false);
        super.setUp();
    }

    /**
     * Test default constructor.
     */
    public void testDefaultConstructor() {
        FileAlterationMonitor monitor = new FileAlterationMonitor();
        assertEquals("Interval", 10000, monitor.getInterval());
    }

    /**
     * Test add/remove observers.
     */
    public void testAddRemoveObservers() {
        FileAlterationObserver[] observers = null;
        FileAlterationMonitor monitor = null;
        
        // Null Observers
        monitor = new FileAlterationMonitor(123, observers);
        assertEquals("Interval", 123, monitor.getInterval());
        assertFalse("Observers[1]", monitor.getObservers().iterator().hasNext());

        // Null Observer
        observers = new FileAlterationObserver[1]; // observer is null
        monitor = new FileAlterationMonitor(456, observers);
        assertFalse("Observers[2]", monitor.getObservers().iterator().hasNext());

        // Null Observer
        monitor.addObserver(null);
        assertFalse("Observers[3]", monitor.getObservers().iterator().hasNext());
        monitor.removeObserver(null);

        // Add Observer
        FileAlterationObserver observer = new FileAlterationObserver("foo");
        monitor.addObserver(observer);
        Iterator<FileAlterationObserver> it = monitor.getObservers().iterator();
        assertTrue("Observers[4]", it.hasNext());
        assertEquals("Added", observer, it.next());
        assertFalse("Observers[5]", it.hasNext());

        // Remove Observer
        monitor.removeObserver(observer);
        assertFalse("Observers[6]", monitor.getObservers().iterator().hasNext());
    }

    /**
     * Test checkAndNotify() method
     */
    public void testMonitor() {
        try {
            long interval = 100;
            FileAlterationMonitor monitor = new FileAlterationMonitor(interval, observer);
            assertEquals("Interval", interval, monitor.getInterval());
            monitor.start();

            try {
                monitor.start(); // try and start again
            } catch (IllegalStateException e) {
                // expected result, monitor already running
            }

            // Create a File
            checkCollectionsEmpty("A");
            File file1 = touch(new File(testDir, "file1.java"));
            checkFile("Create", file1, listener.getCreatedFiles());
            listener.clear();

            // Update a file
            checkCollectionsEmpty("B");
            file1 = touch(file1);
            checkFile("Update", file1, listener.getChangedFiles());
            listener.clear();

            // Delete a file
            checkCollectionsEmpty("C");
            file1.delete();
            checkFile("Delete", file1, listener.getDeletedFiles());
            listener.clear();

            // Stop monitoring
            monitor.stop();

            try {
                monitor.stop(); // try and stop again
            } catch (IllegalStateException e) {
                // expected result, monitor already stopped
            }
        } catch (Exception e) {
            e.printStackTrace();
            fail("Threw " + e);
        }
    }

    /**
     * Check all the File Collections have the expected sizes.
     */
    private void checkFile(String label, File file, Collection<File> files) {
        for (int i = 0; i < 20; i++) {
            if (files.contains(file)) {
                return; // found, test passes
            }
            sleepHandleInterruped(pauseTime);
        }
        fail(label + " " + file + " not found");
    }
}