Some simple file I-O primitives reimplemented in Java : Data Input Output « File Input Output « Java






Some simple file I-O primitives reimplemented in Java

 
/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;

/**
 * Some simple file I-O primitives reimplemented in Java. All methods are
 * static, since there is no state.
 * 
 * @version $Id: FileIO.java,v 1.18 2004/05/30 01:39:27 ian Exp $
 */
public class FileIO {

  /** Nobody should need to create an instance; all methods are static */
  private FileIO() {
    // Nothing to do
  }

  /** Copy a file from one filename to another */
  public static void copyFile(String inName, String outName)
      throws FileNotFoundException, IOException {
    BufferedInputStream is = new BufferedInputStream(new FileInputStream(
        inName));
    BufferedOutputStream os = new BufferedOutputStream(
        new FileOutputStream(outName));
    copyFile(is, os, true);
  }

  /** Copy a file from an opened InputStream to opened OutputStream */
  public static void copyFile(InputStream is, OutputStream os, boolean close)
      throws IOException {
    byte[] b = new byte[BLKSIZ]; // the byte read from the file
    int i;
    while ((i = is.read(b)) != -1) {
      os.write(b, 0, i);
    }
    is.close();
    if (close)
      os.close();
  }

  /** Copy a file from an opened Reader to opened Writer */
  public static void copyFile(Reader is, Writer os, boolean close)
      throws IOException {
    int b; // the byte read from the file
    BufferedReader bis = new BufferedReader(is);
    while ((b = is.read()) != -1) {
      os.write(b);
    }
    is.close();
    if (close)
      os.close();
  }

  /** Copy a file from a filename to a PrintWriter. */
  public static void copyFile(String inName, PrintWriter pw, boolean close)
      throws FileNotFoundException, IOException {
    BufferedReader ir = new BufferedReader(new FileReader(inName));
    copyFile(ir, pw, close);
  }

  /** Open a file and read the first line from it. */
  public static String readLine(String inName) throws FileNotFoundException,
      IOException {
    BufferedReader is = new BufferedReader(new FileReader(inName));
    String line = null;
    line = is.readLine();
    is.close();
    return line;
  }

  /** The size of blocking to use */
  protected static final int BLKSIZ = 16384;

  /**
   * Copy a data file from one filename to another, alternate method. As the
   * name suggests, use my own buffer instead of letting the BufferedReader
   * allocate and use the buffer.
   */
  public void copyFileBuffered(String inName, String outName)
      throws FileNotFoundException, IOException {
    InputStream is = new FileInputStream(inName);
    OutputStream os = new FileOutputStream(outName);
    int count = 0; // the byte count
    byte[] b = new byte[BLKSIZ]; // the bytes read from the file
    while ((count = is.read(b)) != -1) {
      os.write(b, 0, count);
    }
    is.close();
    os.close();
  }

  /** Read the entire content of a Reader into a String */
  public static String readerToString(Reader is) throws IOException {
    StringBuffer sb = new StringBuffer();
    char[] b = new char[BLKSIZ];
    int n;

    // Read a block. If it gets any chars, append them.
    while ((n = is.read(b)) > 0) {
      sb.append(b, 0, n);
    }

    // Only construct the String object once, here.
    return sb.toString();
  }

  /** Read the content of a Stream into a String */
  public static String inputStreamToString(InputStream is) throws IOException {
    return readerToString(new InputStreamReader(is));
  }

  /** Write a String as the entire content of a File */
  public static void stringToFile(String text, String fileName)
      throws IOException {
    BufferedWriter os = new BufferedWriter(new FileWriter(fileName));
    os.write(text);
    os.flush();
    os.close();
  }

  /** Open a BufferedReader from a named file. */
  public static BufferedReader openFile(String fileName) throws IOException {
    return new BufferedReader(new FileReader(fileName));
  }
}

           
         
  








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