Commons IO example source code file (FileWriterWithEncoding.java)

This example Commons IO source code file (FileWriterWithEncoding.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

charset, charsetencoder, file, file, filewriterwithencoding, filewriterwithencoding, io, ioexception, ioexception, nullpointerexception, outputstreamwriter, override, override, string, writer

The Commons IO FileWriterWithEncoding.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.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

/**
 * Writer of files that allows the encoding to be set.
 * <p>
 * This class provides a simple alternative to <code>FileWriter
 * that allows an encoding to be set. Unfortunately, it cannot subclass
 * <code>FileWriter.
 * <p>
 * By default, the file will be overwritten, but this may be changed to append.
 * <p>
 * The encoding must be specified using either the name of the {@link Charset},
 * the {@link Charset}, or a {@link CharsetEncoder}. If the default encoding
 * is required then use the {@link java.io.FileWriter} directly, rather than
 * this implementation.
 * <p>
 * 
 *
 * @since Commons IO 1.4
 * @version $Id: FileWriterWithEncoding.java 659817 2008-05-24 13:23:10Z niallp $
 */
public class FileWriterWithEncoding extends Writer {
    // Cannot extend ProxyWriter, as requires writer to be
    // known when super() is called

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

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, String encoding) throws IOException {
        this(new File(filename), encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, String encoding, boolean append) throws IOException {
        this(new File(filename), encoding, append);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, Charset encoding) throws IOException {
        this(new File(filename), encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, Charset encoding, boolean append) throws IOException {
        this(new File(filename), encoding, append);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, CharsetEncoder encoding) throws IOException {
        this(new File(filename), encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param filename  the name of the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file name or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(String filename, CharsetEncoder encoding, boolean append) throws IOException {
        this(new File(filename), encoding, append);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, String encoding) throws IOException {
        this(file, encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, String encoding, boolean append) throws IOException {
        super();
        this.out = initWriter(file, encoding, append);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, Charset encoding) throws IOException {
        this(file, encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, Charset encoding, boolean append) throws IOException {
        super();
        this.out = initWriter(file, encoding, append);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, CharsetEncoder encoding) throws IOException {
        this(file, encoding, false);
    }

    /**
     * Constructs a FileWriterWithEncoding with a file encoding.
     *
     * @param file  the file to write to, not null
     * @param encoding  the encoding to use, not null
     * @param append  true if content should be appended, false to overwrite
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException in case of an I/O error
     */
    public FileWriterWithEncoding(File file, CharsetEncoder encoding, boolean append) throws IOException {
        super();
        this.out = initWriter(file, encoding, append);
    }

    //-----------------------------------------------------------------------
    /**
     * Initialise the wrapped file writer.
     * Ensure that a cleanup occurs if the writer creation fails.
     *
     * @param file  the file to be accessed
     * @param encoding  the encoding to use - may be Charset, CharsetEncoder or String
     * @param append  true to append
     * @return the initialised writer
     * @throws NullPointerException if the file or encoding is null
     * @throws IOException if an error occurs
     */
     private static Writer initWriter(File file, Object encoding, boolean append) throws IOException {
        if (file == null) {
            throw new NullPointerException("File is missing");
        }
        if (encoding == null) {
            throw new NullPointerException("Encoding is missing");
        }
        boolean fileExistedAlready = file.exists();
        OutputStream stream = null;
        Writer writer = null;
        try {
            stream = new FileOutputStream(file, append);
            if (encoding instanceof Charset) {
                writer = new OutputStreamWriter(stream, (Charset)encoding);
            } else if (encoding instanceof CharsetEncoder) {
                writer = new OutputStreamWriter(stream, (CharsetEncoder)encoding);
            } else {
                writer = new OutputStreamWriter(stream, (String)encoding);
            }
        } catch (IOException ex) {
            IOUtils.closeQuietly(writer);
            IOUtils.closeQuietly(stream);
            if (fileExistedAlready == false) {
                FileUtils.deleteQuietly(file);
            }
            throw ex;
        } catch (RuntimeException ex) {
            IOUtils.closeQuietly(writer);
            IOUtils.closeQuietly(stream);
            if (fileExistedAlready == false) {
                FileUtils.deleteQuietly(file);
            }
            throw ex;
        }
        return writer;
    }

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

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

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

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

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

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

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