src/main/java/org/apache/commons/io/output/LockableFileWriter.java - commons-io - Git at Google

 /*
  * 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.FileOutputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.nio.charset.Charset;
 import java.util.Objects;

 import org.apache.commons.io.Charsets;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.build.AbstractOrigin;
 import org.apache.commons.io.build.AbstractOriginSupplier;
 import org.apache.commons.io.build.AbstractStreamBuilder;

 /**
  * FileWriter that will create and honor lock files to allow simple cross thread file lock handling.
  * <p>
  * This class provides a simple alternative to {@link FileWriter} that will use a lock file to prevent duplicate writes.
  * </p>
  * <p>
  * <b>Note:</b> The lock file is deleted when {@link #close()} is called - or if the main file cannot be opened initially. In the (unlikely) event that the lock
  * file cannot be deleted, an exception is thrown.
  * </p>
  * <p>
  * By default, the file will be overwritten, but this may be changed to append. The lock directory may be specified, but defaults to the system property
  * {@code java.io.tmpdir}. The encoding may also be specified, and defaults to the platform default.
  * </p>
  * <p>
  * To build an instance, see {@link Builder}.
  * </p>
  */
 public class LockableFileWriter extends Writer {

     // @formatter:off
     /**
      * Builds a new {@link LockableFileWriter} instance.
      * <p>
      * Using a CharsetEncoder:
      * </p>
      * <pre>{@code
      * LockableFileWriter w = LockableFileWriter.builder()
      *   .setPath(path)
      *   .setAppend(false)
      *   .setLockDirectory("Some/Directory")
      *   .get();}
      * </pre>
      *
      * @since 2.12.0
      */
     // @formatter:on
     public static class Builder extends AbstractStreamBuilder<LockableFileWriter, Builder> {

         private boolean append;
         private AbstractOrigin<?, ?> lockDirectory = AbstractOriginSupplier.newFileOrigin(FileUtils.getTempDirectoryPath());

         /**
          * Constructs a new Builder.
          */
         public Builder() {
             setBufferSizeDefault(AbstractByteArrayOutputStream.DEFAULT_SIZE);
             setBufferSize(AbstractByteArrayOutputStream.DEFAULT_SIZE);
         }

         /**
          * Constructs a new instance.
          * <p>
          * This builder use the aspects File, Charset, append, and lockDirectory.
          * </p>
          * <p>
          * You must provide an origin that can be converted to a File by this builder, otherwise, this call will throw an
          * {@link UnsupportedOperationException}.
          * </p>
          *
          * @return a new instance.
          * @throws UnsupportedOperationException if the origin cannot provide a File.
          * @throws IllegalStateException if the {@code origin} is {@code null}.
          * @see AbstractOrigin#getFile()
          */
         @Override
         public LockableFileWriter get() throws IOException {
             return new LockableFileWriter(checkOrigin().getFile(), getCharset(), append, lockDirectory.getFile().toString());
         }

         /**
          * Sets whether to append (true) or overwrite (false).
          *
          * @param append whether to append (true) or overwrite (false).
          * @return this
          */
         public Builder setAppend(final boolean append) {
             this.append = append;
             return this;
         }

         /**
          * Sets the directory in which the lock file should be held.
          *
          * @param lockDirectory the directory in which the lock file should be held.
          * @return this
          */
         public Builder setLockDirectory(final File lockDirectory) {
             this.lockDirectory = AbstractOriginSupplier.newFileOrigin(lockDirectory != null ? lockDirectory : FileUtils.getTempDirectory());
             return this;
         }

         /**
          * Sets the directory in which the lock file should be held.
          *
          * @param lockDirectory the directory in which the lock file should be held.
          * @return this
          */
         public Builder setLockDirectory(final String lockDirectory) {
             this.lockDirectory = AbstractOriginSupplier.newFileOrigin(lockDirectory != null ? lockDirectory : FileUtils.getTempDirectoryPath());
             return this;
         }

     }

     /** The extension for the lock file. */
     private static final String LCK = ".lck";

     // Cannot extend ProxyWriter, as requires writer to be
     // known when super() is called

     /**
      * Constructs a new {@link Builder}.
      *
      * @return a new {@link Builder}.
      * @since 2.12.0
      */
     public static Builder builder() {
         return new Builder();
     }

     /** The writer to decorate. */
     private final Writer out;

     /** The lock file. */
     private final File lockFile;

     /**
      * Constructs a LockableFileWriter. If the file exists, it is overwritten.
      *
      * @param file the file to write to, not null
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file) throws IOException {
         this(file, false, null);
     }

     /**
      * Constructs a LockableFileWriter.
      *
      * @param file   the file to write to, not null
      * @param append true if content should be appended, false to overwrite
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file, final boolean append) throws IOException {
         this(file, append, null);
     }

     /**
      * Constructs a LockableFileWriter.
      *
      * @param file    the file to write to, not null
      * @param append  true if content should be appended, false to overwrite
      * @param lockDir the directory in which the lock file should be held
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #LockableFileWriter(File, Charset, boolean, String)} instead
      */
     @Deprecated
     public LockableFileWriter(final File file, final boolean append, final String lockDir) throws IOException {
         this(file, Charset.defaultCharset(), append, lockDir);
     }

     /**
      * Constructs a LockableFileWriter with a file encoding.
      *
      * @param file    the file to write to, not null
      * @param charset the charset to use, null means platform default
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @since 2.3
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file, final Charset charset) throws IOException {
         this(file, charset, false, null);
     }

     /**
      * Constructs a LockableFileWriter with a file encoding.
      *
      * @param file    the file to write to, not null
      * @param charset the name of the requested charset, null means platform default
      * @param append  true if content should be appended, false to overwrite
      * @param lockDir the directory in which the lock file should be held
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @since 2.3
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file, final Charset charset, final boolean append, final String lockDir) throws IOException {
         // init file to create/append
         final File absFile = Objects.requireNonNull(file, "file").getAbsoluteFile();
         if (absFile.getParentFile() != null) {
             FileUtils.forceMkdir(absFile.getParentFile());
         }
         if (absFile.isDirectory()) {
             throw new IOException("File specified is a directory");
         }

         // init lock file
         final File lockDirFile = new File(lockDir != null ? lockDir : FileUtils.getTempDirectoryPath());
         FileUtils.forceMkdir(lockDirFile);
         testLockDir(lockDirFile);
         lockFile = new File(lockDirFile, absFile.getName() + LCK);

         // check if locked
         createLock();

         // init wrapped writer
         out = initWriter(absFile, charset, append);
     }

     /**
      * Constructs a LockableFileWriter with a file encoding.
      *
      * @param file        the file to write to, not null
      * @param charsetName the name of the requested charset, null means platform default
      * @throws NullPointerException                         if the file is null
      * @throws IOException                                  in case of an I/O error
      * @throws java.nio.charset.UnsupportedCharsetException thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not
      *                                                      supported.
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file, final String charsetName) throws IOException {
         this(file, charsetName, false, null);
     }

     /**
      * Constructs a LockableFileWriter with a file encoding.
      *
      * @param file        the file to write to, not null
      * @param charsetName the encoding to use, null means platform default
      * @param append      true if content should be appended, false to overwrite
      * @param lockDir     the directory in which the lock file should be held
      * @throws NullPointerException                         if the file is null
      * @throws IOException                                  in case of an I/O error
      * @throws java.nio.charset.UnsupportedCharsetException thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not
      *                                                      supported.
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final File file, final String charsetName, final boolean append, final String lockDir) throws IOException {
         this(file, Charsets.toCharset(charsetName), append, lockDir);
     }

     /**
      * Constructs a LockableFileWriter. If the file exists, it is overwritten.
      *
      * @param fileName the file to write to, not null
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final String fileName) throws IOException {
         this(fileName, false, null);
     }

     /**
      * Constructs a LockableFileWriter.
      *
      * @param fileName file to write to, not null
      * @param append   true if content should be appended, false to overwrite
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final String fileName, final boolean append) throws IOException {
         this(fileName, append, null);
     }

     /**
      * Constructs a LockableFileWriter.
      *
      * @param fileName the file to write to, not null
      * @param append   true if content should be appended, false to overwrite
      * @param lockDir  the directory in which the lock file should be held
      * @throws NullPointerException if the file is null
      * @throws IOException          in case of an I/O error
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public LockableFileWriter(final String fileName, final boolean append, final String lockDir) throws IOException {
         this(new File(fileName), append, lockDir);
     }

     /**
      * Closes the file writer and deletes the lock file.
      *
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void close() throws IOException {
         try {
             out.close();
         } finally {
             FileUtils.delete(lockFile);
         }
     }

     /**
      * Creates the lock file.
      *
      * @throws IOException if we cannot create the file
      */
     private void createLock() throws IOException {
         synchronized (LockableFileWriter.class) {
             if (!lockFile.createNewFile()) {
                 throw new IOException("Can't write file, lock " + lockFile.getAbsolutePath() + " exists");
             }
             lockFile.deleteOnExit();
         }
     }

     /**
      * Flushes the stream.
      *
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void flush() throws IOException {
         out.flush();
     }

     /**
      * Initializes the wrapped file writer. Ensure that a cleanup occurs if the writer creation fails.
      *
      * @param file    the file to be accessed
      * @param charset the charset to use
      * @param append  true to append
      * @return The initialized writer
      * @throws IOException if an error occurs
      */
     private Writer initWriter(final File file, final Charset charset, final boolean append) throws IOException {
         final boolean fileExistedAlready = file.exists();
         try {
             return new OutputStreamWriter(new FileOutputStream(file.getAbsolutePath(), append), Charsets.toCharset(charset));

         } catch (final IOException | RuntimeException ex) {
             FileUtils.deleteQuietly(lockFile);
             if (!fileExistedAlready) {
                 FileUtils.deleteQuietly(file);
             }
             throw ex;
         }
     }

     /**
      * Tests that we can write to the lock directory.
      *
      * @param lockDir the File representing the lock directory
      * @throws IOException if we cannot write to the lock directory
      * @throws IOException if we cannot find the lock file
      */
     private void testLockDir(final File lockDir) throws IOException {
         if (!lockDir.exists()) {
             throw new IOException("Could not find lockDir: " + lockDir.getAbsolutePath());
         }
         if (!lockDir.canWrite()) {
             throw new IOException("Could not write to lockDir: " + lockDir.getAbsolutePath());
         }
     }

     /**
      * Writes the characters from an array.
      *
      * @param cbuf the characters to write
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void write(final char[] cbuf) throws IOException {
         out.write(cbuf);
     }

     /**
      * Writes the specified characters from an array.
      *
      * @param cbuf the characters to write
      * @param off  The start offset
      * @param len  The number of characters to write
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void write(final char[] cbuf, final int off, final int len) throws IOException {
         out.write(cbuf, off, len);
     }

     /**
      * Writes a character.
      *
      * @param c the character to write
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void write(final int c) throws IOException {
         out.write(c);
     }

     /**
      * Writes the characters from a string.
      *
      * @param str the string to write
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void write(final String str) throws IOException {
         out.write(str);
     }

     /**
      * Writes the specified characters from a string.
      *
      * @param str the string to write
      * @param off The start offset
      * @param len The number of characters to write
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void write(final String str, final int off, final int len) throws IOException {
         out.write(str, off, len);
     }

 }
	/*
	* 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.FileOutputStream;
	import java.io.FileWriter;
	import java.io.IOException;
	import java.io.OutputStreamWriter;
	import java.io.Writer;
	import java.nio.charset.Charset;
	import java.util.Objects;

	import org.apache.commons.io.Charsets;
	import org.apache.commons.io.FileUtils;
	import org.apache.commons.io.build.AbstractOrigin;
	import org.apache.commons.io.build.AbstractOriginSupplier;
	import org.apache.commons.io.build.AbstractStreamBuilder;

	/**
	* FileWriter that will create and honor lock files to allow simple cross thread file lock handling.
	* <p>
	* This class provides a simple alternative to {@link FileWriter} that will use a lock file to prevent duplicate writes.
	* </p>
	* <p>
	* <b>Note:</b> The lock file is deleted when {@link #close()} is called - or if the main file cannot be opened initially. In the (unlikely) event that the lock
	* file cannot be deleted, an exception is thrown.
	* </p>
	* <p>
	* By default, the file will be overwritten, but this may be changed to append. The lock directory may be specified, but defaults to the system property
	* {@code java.io.tmpdir}. The encoding may also be specified, and defaults to the platform default.
	* </p>
	* <p>
	* To build an instance, see {@link Builder}.
	* </p>
	*/
	public class LockableFileWriter extends Writer {

	// @formatter:off
	/**
	* Builds a new {@link LockableFileWriter} instance.
	* <p>
	* Using a CharsetEncoder:
	* </p>
	* <pre>{@code
	* LockableFileWriter w = LockableFileWriter.builder()
	* .setPath(path)
	* .setAppend(false)
	* .setLockDirectory("Some/Directory")
	* .get();}
	* </pre>
	*
	* @since 2.12.0
	*/
	// @formatter:on
	public static class Builder extends AbstractStreamBuilder<LockableFileWriter, Builder> {

	private boolean append;
	private AbstractOrigin<?, ?> lockDirectory = AbstractOriginSupplier.newFileOrigin(FileUtils.getTempDirectoryPath());

	/**
	* Constructs a new Builder.
	*/
	public Builder() {
	setBufferSizeDefault(AbstractByteArrayOutputStream.DEFAULT_SIZE);
	setBufferSize(AbstractByteArrayOutputStream.DEFAULT_SIZE);
	}

	/**
	* Constructs a new instance.
	* <p>
	* This builder use the aspects File, Charset, append, and lockDirectory.
	* </p>
	* <p>
	* You must provide an origin that can be converted to a File by this builder, otherwise, this call will throw an
	* {@link UnsupportedOperationException}.
	* </p>
	*
	* @return a new instance.
	* @throws UnsupportedOperationException if the origin cannot provide a File.
	* @throws IllegalStateException if the {@code origin} is {@code null}.
	* @see AbstractOrigin#getFile()
	*/
	@Override
	public LockableFileWriter get() throws IOException {
	return new LockableFileWriter(checkOrigin().getFile(), getCharset(), append, lockDirectory.getFile().toString());
	}

	/**
	* Sets whether to append (true) or overwrite (false).
	*
	* @param append whether to append (true) or overwrite (false).
	* @return this
	*/
	public Builder setAppend(final boolean append) {
	this.append = append;
	return this;
	}

	/**
	* Sets the directory in which the lock file should be held.
	*
	* @param lockDirectory the directory in which the lock file should be held.
	* @return this
	*/
	public Builder setLockDirectory(final File lockDirectory) {
	this.lockDirectory = AbstractOriginSupplier.newFileOrigin(lockDirectory != null ? lockDirectory : FileUtils.getTempDirectory());
	return this;
	}

	/**
	* Sets the directory in which the lock file should be held.
	*
	* @param lockDirectory the directory in which the lock file should be held.
	* @return this
	*/
	public Builder setLockDirectory(final String lockDirectory) {
	this.lockDirectory = AbstractOriginSupplier.newFileOrigin(lockDirectory != null ? lockDirectory : FileUtils.getTempDirectoryPath());
	return this;
	}

	}

	/** The extension for the lock file. */
	private static final String LCK = ".lck";

	// Cannot extend ProxyWriter, as requires writer to be
	// known when super() is called

	/**
	* Constructs a new {@link Builder}.
	*
	* @return a new {@link Builder}.
	* @since 2.12.0
	*/
	public static Builder builder() {
	return new Builder();
	}

	/** The writer to decorate. */
	private final Writer out;

	/** The lock file. */
	private final File lockFile;

	/**
	* Constructs a LockableFileWriter. If the file exists, it is overwritten.
	*
	* @param file the file to write to, not null
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file) throws IOException {
	this(file, false, null);
	}

	/**
	* Constructs a LockableFileWriter.
	*
	* @param file the file to write to, not null
	* @param append true if content should be appended, false to overwrite
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file, final boolean append) throws IOException {
	this(file, append, null);
	}

	/**
	* Constructs a LockableFileWriter.
	*
	* @param file the file to write to, not null
	* @param append true if content should be appended, false to overwrite
	* @param lockDir the directory in which the lock file should be held
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #LockableFileWriter(File, Charset, boolean, String)} instead
	*/
	@Deprecated
	public LockableFileWriter(final File file, final boolean append, final String lockDir) throws IOException {
	this(file, Charset.defaultCharset(), append, lockDir);
	}

	/**
	* Constructs a LockableFileWriter with a file encoding.
	*
	* @param file the file to write to, not null
	* @param charset the charset to use, null means platform default
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @since 2.3
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file, final Charset charset) throws IOException {
	this(file, charset, false, null);
	}

	/**
	* Constructs a LockableFileWriter with a file encoding.
	*
	* @param file the file to write to, not null
	* @param charset the name of the requested charset, null means platform default
	* @param append true if content should be appended, false to overwrite
	* @param lockDir the directory in which the lock file should be held
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @since 2.3
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file, final Charset charset, final boolean append, final String lockDir) throws IOException {
	// init file to create/append
	final File absFile = Objects.requireNonNull(file, "file").getAbsoluteFile();
	if (absFile.getParentFile() != null) {
	FileUtils.forceMkdir(absFile.getParentFile());
	}
	if (absFile.isDirectory()) {
	throw new IOException("File specified is a directory");
	}

	// init lock file
	final File lockDirFile = new File(lockDir != null ? lockDir : FileUtils.getTempDirectoryPath());
	FileUtils.forceMkdir(lockDirFile);
	testLockDir(lockDirFile);
	lockFile = new File(lockDirFile, absFile.getName() + LCK);

	// check if locked
	createLock();

	// init wrapped writer
	out = initWriter(absFile, charset, append);
	}

	/**
	* Constructs a LockableFileWriter with a file encoding.
	*
	* @param file the file to write to, not null
	* @param charsetName the name of the requested charset, null means platform default
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @throws java.nio.charset.UnsupportedCharsetException thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not
	* supported.
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file, final String charsetName) throws IOException {
	this(file, charsetName, false, null);
	}

	/**
	* Constructs a LockableFileWriter with a file encoding.
	*
	* @param file the file to write to, not null
	* @param charsetName the encoding to use, null means platform default
	* @param append true if content should be appended, false to overwrite
	* @param lockDir the directory in which the lock file should be held
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @throws java.nio.charset.UnsupportedCharsetException thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not
	* supported.
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final File file, final String charsetName, final boolean append, final String lockDir) throws IOException {
	this(file, Charsets.toCharset(charsetName), append, lockDir);
	}

	/**
	* Constructs a LockableFileWriter. If the file exists, it is overwritten.
	*
	* @param fileName the file to write to, not null
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final String fileName) throws IOException {
	this(fileName, false, null);
	}

	/**
	* Constructs a LockableFileWriter.
	*
	* @param fileName file to write to, not null
	* @param append true if content should be appended, false to overwrite
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final String fileName, final boolean append) throws IOException {
	this(fileName, append, null);
	}

	/**
	* Constructs a LockableFileWriter.
	*
	* @param fileName the file to write to, not null
	* @param append true if content should be appended, false to overwrite
	* @param lockDir the directory in which the lock file should be held
	* @throws NullPointerException if the file is null
	* @throws IOException in case of an I/O error
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public LockableFileWriter(final String fileName, final boolean append, final String lockDir) throws IOException {
	this(new File(fileName), append, lockDir);
	}

	/**
	* Closes the file writer and deletes the lock file.
	*
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void close() throws IOException {
	try {
	out.close();
	} finally {
	FileUtils.delete(lockFile);
	}
	}

	/**
	* Creates the lock file.
	*
	* @throws IOException if we cannot create the file
	*/
	private void createLock() throws IOException {
	synchronized (LockableFileWriter.class) {
	if (!lockFile.createNewFile()) {
	throw new IOException("Can't write file, lock " + lockFile.getAbsolutePath() + " exists");
	}
	lockFile.deleteOnExit();
	}
	}

	/**
	* Flushes the stream.
	*
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void flush() throws IOException {
	out.flush();
	}

	/**
	* Initializes the wrapped file writer. Ensure that a cleanup occurs if the writer creation fails.
	*
	* @param file the file to be accessed
	* @param charset the charset to use
	* @param append true to append
	* @return The initialized writer
	* @throws IOException if an error occurs
	*/
	private Writer initWriter(final File file, final Charset charset, final boolean append) throws IOException {
	final boolean fileExistedAlready = file.exists();
	try {
	return new OutputStreamWriter(new FileOutputStream(file.getAbsolutePath(), append), Charsets.toCharset(charset));

	} catch (final IOException \| RuntimeException ex) {
	FileUtils.deleteQuietly(lockFile);
	if (!fileExistedAlready) {
	FileUtils.deleteQuietly(file);
	}
	throw ex;
	}
	}

	/**
	* Tests that we can write to the lock directory.
	*
	* @param lockDir the File representing the lock directory
	* @throws IOException if we cannot write to the lock directory
	* @throws IOException if we cannot find the lock file
	*/
	private void testLockDir(final File lockDir) throws IOException {
	if (!lockDir.exists()) {
	throw new IOException("Could not find lockDir: " + lockDir.getAbsolutePath());
	}
	if (!lockDir.canWrite()) {
	throw new IOException("Could not write to lockDir: " + lockDir.getAbsolutePath());
	}
	}

	/**
	* Writes the characters from an array.
	*
	* @param cbuf the characters to write
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void write(final char[] cbuf) throws IOException {
	out.write(cbuf);
	}

	/**
	* Writes the specified characters from an array.
	*
	* @param cbuf the characters to write
	* @param off The start offset
	* @param len The number of characters to write
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void write(final char[] cbuf, final int off, final int len) throws IOException {
	out.write(cbuf, off, len);
	}

	/**
	* Writes a character.
	*
	* @param c the character to write
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void write(final int c) throws IOException {
	out.write(c);
	}

	/**
	* Writes the characters from a string.
	*
	* @param str the string to write
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void write(final String str) throws IOException {
	out.write(str);
	}

	/**
	* Writes the specified characters from a string.
	*
	* @param str the string to write
	* @param off The start offset
	* @param len The number of characters to write
	* @throws IOException if an I/O error occurs.
	*/
	@Override
	public void write(final String str, final int off, final int len) throws IOException {
	out.write(str, off, len);
	}

	}