org.apache.commons.io.output.FileWriterWithEncoding Maven / Gradle / Ivy
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/*
* 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;
/**
* Writer of files that allows the encoding to be set.
*
* This class provides a simple alternative to FileWriter
* that allows an encoding to be set. Unfortunately, it cannot subclass
* FileWriter.
*
* By default, the file will be overwritten, but this may be changed to append.
*
* 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.
*
*
*
* @since 1.4
* @version $Id$
*/
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(final String filename, final 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(final String filename, final String encoding, final 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(final String filename, final 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(final String filename, final Charset encoding, final 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(final String filename, final 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(final String filename, final CharsetEncoder encoding, final 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(final File file, final 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(final File file, final String encoding, final 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(final File file, final 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(final File file, final Charset encoding, final 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(final File file, final 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(final File file, final CharsetEncoder encoding, final 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(final File file, final Object encoding, final boolean append) throws IOException {
if (file == null) {
throw new NullPointerException("File is missing");
}
if (encoding == null) {
throw new NullPointerException("Encoding is missing");
}
OutputStream stream = null;
final boolean fileExistedAlready = file.exists();
try {
stream = new FileOutputStream(file, append);
if (encoding instanceof Charset) {
return new OutputStreamWriter(stream, (Charset)encoding);
} else if (encoding instanceof CharsetEncoder) {
return new OutputStreamWriter(stream, (CharsetEncoder)encoding);
} else {
return new OutputStreamWriter(stream, (String)encoding);
}
} catch (final IOException | RuntimeException ex) {
try {
if (stream != null) {
stream.close();
}
} catch (final IOException e) {
ex.addSuppressed(e);
}
if (fileExistedAlready == false) {
FileUtils.deleteQuietly(file);
}
throw ex;
}
}
//-----------------------------------------------------------------------
/**
* Write a character.
* @param idx the character to write
* @throws IOException if an I/O error occurs
*/
@Override
public void write(final 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(final 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(final char[] chr, final int st, final 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(final 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(final String str, final int st, final 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();
}
}