Commons IO example source code file (LockableFileWriterTest.java)

This example Commons IO source code file (LockableFileWriterTest.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

can't, exception, file, file, io, ioexception, ioexception, lockablefilewriter, lockablefilewriter, lockablefilewritertest, override, somehow, string, writer, writer

The Commons IO LockableFileWriterTest.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.output;

import java.io.File;
import java.io.IOException;
import java.io.Writer;

import org.apache.commons.io.IOUtils;
import org.apache.commons.io.testtools.FileBasedTestCase;

/**
 * Tests that files really lock, although no writing is done as 
 * the locking is tested only on construction. 
 *
 * @version $Revision: 806007 $ $Date: 2009-08-20 00:03:11 +0100 (Thu, 20 Aug 2009) $
 */
public class LockableFileWriterTest extends FileBasedTestCase {

    private File file;
    private File lockDir;
    private File lockFile;
    private File altLockDir;
    private File altLockFile;

    public LockableFileWriterTest(String name) {
        super(name);
    }

    @Override
    public void setUp() {
        file = new File(getTestDirectory(), "testlockfile");
        lockDir = new File(System.getProperty("java.io.tmpdir"));
        lockFile = new File(lockDir, file.getName() + ".lck");
        altLockDir = getTestDirectory();
        altLockFile = new File(altLockDir, file.getName() + ".lck");
    }

    @Override
    public void tearDown() {
        file.delete();
        lockFile.delete();
        altLockFile.delete();
    }

    //-----------------------------------------------------------------------
    public void testFileLocked() throws IOException {
        LockableFileWriter lfw1 = null;
        LockableFileWriter lfw2 = null;
        LockableFileWriter lfw3 = null;
        try {
            // open a valid locakable writer
            lfw1 = new LockableFileWriter(file);
            assertEquals(true, file.exists());
            assertEquals(true, lockFile.exists());
            
            // try to open a second writer
            try {
                lfw2 = new LockableFileWriter(file);
                fail("Somehow able to open a locked file. ");
            } catch(IOException ioe) {
                String msg = ioe.getMessage();
                assertTrue( "Exception message does not start correctly. ", 
                            msg.startsWith("Can't write file, lock ") );
                assertEquals(true, file.exists());
                assertEquals(true, lockFile.exists());
            }
            
            // try to open a third writer
            try {
                lfw3 = new LockableFileWriter(file);
                fail("Somehow able to open a locked file. ");
            } catch(IOException ioe) {
                String msg = ioe.getMessage();
                assertTrue( "Exception message does not start correctly. ", 
                            msg.startsWith("Can't write file, lock ") );
                assertEquals(true, file.exists());
                assertEquals(true, lockFile.exists());
            }
            
        } finally {
            IOUtils.closeQuietly(lfw1);
            IOUtils.closeQuietly(lfw2);
            IOUtils.closeQuietly(lfw3);
        }
        assertEquals(true, file.exists());
        assertEquals(false, lockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testAlternateLockDir() throws IOException {
        LockableFileWriter lfw1 = null;
        LockableFileWriter lfw2 = null;
        try {
            // open a valid locakable writer
            lfw1 = new LockableFileWriter(file, true, altLockDir.getAbsolutePath());
            assertEquals(true, file.exists());
            assertEquals(true, altLockFile.exists());
            
            // try to open a second writer
            try {
                lfw2 = new LockableFileWriter(file, true, altLockDir.getAbsolutePath());
                fail("Somehow able to open a locked file. ");
            } catch(IOException ioe) {
                String msg = ioe.getMessage();
                assertTrue( "Exception message does not start correctly. ", 
                            msg.startsWith("Can't write file, lock ") );
                assertEquals(true, file.exists());
                assertEquals(true, altLockFile.exists());
            }
            
        } finally {
            IOUtils.closeQuietly(lfw1);
            IOUtils.closeQuietly(lfw2);
        }
        assertEquals(true, file.exists());
        assertEquals(false, altLockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testFileNotLocked() throws IOException {
        // open a valid locakable writer
        LockableFileWriter lfw1 = null;
        try {
            lfw1 = new LockableFileWriter(file);
            assertEquals(true, file.exists());
            assertEquals(true, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(lfw1);
        }
        assertEquals(true, file.exists());
        assertEquals(false, lockFile.exists());
        
        // open a second valid writer on the same file
        LockableFileWriter lfw2 = null;
        try {
            lfw2 = new LockableFileWriter(file);
            assertEquals(true, file.exists());
            assertEquals(true, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(lfw2);
        }
        assertEquals(true, file.exists());
        assertEquals(false, lockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testConstructor_File_encoding_badEncoding() {
        Writer writer = null;
        try {
            writer = new LockableFileWriter(file, "BAD-ENCODE");
            fail();
        } catch (IOException ex) {
            // expected
            assertEquals(false, file.exists());
            assertEquals(false, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(writer);
        }
        assertEquals(false, file.exists());
        assertEquals(false, lockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testConstructor_File_directory() {
        Writer writer = null;
        try {
            writer = new LockableFileWriter(getTestDirectory());
            fail();
        } catch (IOException ex) {
            // expected
            assertEquals(false, file.exists());
            assertEquals(false, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(writer);
        }
        assertEquals(false, file.exists());
        assertEquals(false, lockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testConstructor_File_nullFile() throws IOException {
        Writer writer = null;
        try {
            writer = new LockableFileWriter((File) null);
            fail();
        } catch (NullPointerException ex) {
            // expected
            assertEquals(false, file.exists());
            assertEquals(false, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(writer);
        }
        assertEquals(false, file.exists());
        assertEquals(false, lockFile.exists());
    }

    //-----------------------------------------------------------------------
    public void testConstructor_fileName_nullFile() throws IOException {
        Writer writer = null;
        try {
            writer = new LockableFileWriter((String) null);
            fail();
        } catch (NullPointerException ex) {
            // expected
            assertEquals(false, file.exists());
            assertEquals(false, lockFile.exists());
        } finally {
            IOUtils.closeQuietly(writer);
        }
        assertEquals(false, file.exists());
        assertEquals(false, lockFile.exists());
    }

}