Android Text File Write writeFileAtomically(File file, String content, String encoding)

Description

Writes a string to a file, creating the directory if necessary.

License

Apache License

Declaration

public static void writeFileAtomically(File file, String content,
        String encoding) throws IOException 

Method Source Code

/**//w w  w . j a  v a2s.  co m
 *  Copyright 2009 Welocalize, Inc. 
 *  
 *  Licensed 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.
 *  
 */

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.log4j.Logger;

public class Main{
    static private final Logger logger = Logger.getLogger(FileUtil.class);
    /**
     * Writes a string to a file, creating the directory if necessary. The write
     * is done atomically by writing to a temporary file, then renaming the
     * temporary file to the final name. This avoids anyone trying to read the
     * file while it is being written. The temporary file ends in .tmp.
     */
    public static void writeFileAtomically(File file, String content,
            String encoding) throws IOException {
        File parent = file.getParentFile();
        if (!parent.exists()) {
            parent.mkdirs();
        }

        File tmpFile = File.createTempFile("GSFileUtilWFA", ".tmp", parent);
        try {
            Writer out = new OutputStreamWriter(new FileOutputStream(
                    tmpFile), encoding);
            out.write(content);
            out.flush();
            out.close();
            if (!tmpFile.renameTo(file)) {
                throw new IOException("Failed to rename " + tmpFile
                        + " to " + file);
            }
        } finally {
            deleteTempFile(tmpFile);
        }
    }
    /**
     * Delete a temporary file. If the file does not exist, we assume it has
     * aready been cleaned up and succeed quietly. Warns but does not throw an
     * exception if deletion fails. This method should not be called on a
     * directory.
     * 
     * Use this method rather than just calling File.delete because it will log
     * a warning, and may in the future take other measures to delete the file
     * if it can't immediately.
     */
    public static void deleteTempFile(File tmpFile) {
        if (!tmpFile.exists()) {
            return;
        }
        if (!tmpFile.delete()) {
            logger.warn("Failed to delete temporary file " + tmpFile
                    + "; something is probably holding it open");
        }
    }
}

Related

1. writeFileAsString(File file, String text)
2. writeFileAsString(File file, String text, String encoding)
3. writeFileAsString(String filename, String text)
4. writeFileAsString(String filename, String text, String encoding)
5. writeFileAsStringWorldWritable(File file, String text)
6. writeFileWithBom(File file, String content, String encoding)
7. writeLargerTextFile(File file, List aLines)
8. writeLineTextFile(File file, String data)
9. writeLineTextFile(File file, String[] dataArray)