/*

  * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 package java.io;

 /**

  * Writes text to a character-output stream, buffering characters so as to

  * provide for the efficient writing of single characters, arrays, and strings.

  *

  * <p> The buffer size may be specified, or the default size may be accepted.

  * The default is large enough for most purposes.

  *

  * <p> A newLine() method is provided, which uses the platform's own notion of

  * line separator as defined by the system property <tt>line.separator</tt>.

  * Not all platforms use the newline character ('\n') to terminate lines.

  * Calling this method to terminate each output line is therefore preferred to

  * writing a newline character directly.

  *

  * <p> In general, a Writer sends its output immediately to the underlying

  * character or byte stream.  Unless prompt output is required, it is advisable

  * to wrap a BufferedWriter around any Writer whose write() operations may be

  * costly, such as FileWriters and OutputStreamWriters.  For example,

  *

  * <pre>

  * PrintWriter out

  *   = new PrintWriter(new BufferedWriter(new FileWriter("foo.out")));

  * </pre>

  *

  * will buffer the PrintWriter's output to the file.  Without buffering, each

  * invocation of a print() method would cause characters to be converted into

  * bytes that would then be written immediately to the file, which can be very

  * inefficient.

  *

  * @see PrintWriter

  * @see FileWriter

  * @see OutputStreamWriter

  * @see java.nio.file.Files#newBufferedWriter

  *

  * @author      Mark Reinhold

  * @since       JDK1.1

  */

 public class BufferedWriter extends Writer {

     private Writer out;

     private char cb[];

     private int nChars, nextChar;

     private static int defaultCharBufferSize = 8192;

     /**

      * Line separator string.  This is the value of the line.separator

      * property at the moment that the stream was created.

      */

     private String lineSeparator;

     /**

      * Creates a buffered character-output stream that uses a default-sized

      * output buffer.

      *

      * @param  out  A Writer

      */

     public BufferedWriter(Writer out) {

         this(out, defaultCharBufferSize);

     }

     /**

      * Creates a new buffered character-output stream that uses an output

      * buffer of the given size.

      *

      * @param  out  A Writer

      * @param  sz   Output-buffer size, a positive integer

      *

      * @exception  IllegalArgumentException  If sz is <= 0

      */

     public BufferedWriter(Writer out, int sz) {

         super(out);

         if (sz <= 0)

             throw new IllegalArgumentException("Buffer size <= 0");

         this.out = out;

         cb = new char[sz];

         nChars = sz;

         nextChar = 0;

         lineSeparator = java.security.AccessController.doPrivileged(

             new sun.security.action.GetPropertyAction("line.separator"));

     }

     /** Checks to make sure that the stream has not been closed */

     private void ensureOpen() throws IOException {

         if (out == null)

             throw new IOException("Stream closed");

     }

     /**

      * Flushes the output buffer to the underlying character stream, without

      * flushing the stream itself.  This method is non-private only so that it

      * may be invoked by PrintStream.

      */

     void flushBuffer() throws IOException {

         synchronized (lock) {

             ensureOpen();

             if (nextChar == 0)

                 return;

             out.write(cb, 0, nextChar);

             nextChar = 0;

         }

     }

     /**

      * Writes a single character.

      *

      * @exception  IOException  If an I/O error occurs

      */

     public void write(int c) throws IOException {

         synchronized (lock) {

             ensureOpen();

             if (nextChar >= nChars)

                 flushBuffer();

             cb[nextChar++] = (char) c;

         }

     }

     /**

      * Our own little min method, to avoid loading java.lang.Math if we've run

      * out of file descriptors and we're trying to print a stack trace.

      */

     private int min(int a, int b) {

         if (a < b) return a;

         return b;

     }

     /**

      * Writes a portion of an array of characters.

      *

      * <p> Ordinarily this method stores characters from the given array into

      * this stream's buffer, flushing the buffer to the underlying stream as

      * needed.  If the requested length is at least as large as the buffer,

      * however, then this method will flush the buffer and write the characters

      * directly to the underlying stream.  Thus redundant

      * <code>BufferedWriter</code>s will not copy data unnecessarily.

      *

      * @param  cbuf  A character array

      * @param  off   Offset from which to start reading characters

      * @param  len   Number of characters to write

      *

      * @exception  IOException  If an I/O error occurs

      */

     public void write(char cbuf[], int off, int len) throws IOException {

         synchronized (lock) {

             ensureOpen();

             if ((off < 0) || (off > cbuf.length) || (len < 0) ||

                 ((off + len) > cbuf.length) || ((off + len) < 0)) {

                 throw new IndexOutOfBoundsException();

             } else if (len == 0) {

                 return;

             }

             if (len >= nChars) {

                 /* If the request length exceeds the size of the output buffer,

                    flush the buffer and then write the data directly.  In this

                    way buffered streams will cascade harmlessly. */

                 flushBuffer();

                 out.write(cbuf, off, len);

                 return;

             }

             int b = off, t = off + len;

             while (b < t) {

                 int d = min(nChars - nextChar, t - b);

                 System.arraycopy(cbuf, b, cb, nextChar, d);

                 b += d;

                 nextChar += d;

                 if (nextChar >= nChars)

                     flushBuffer();

             }

         }

     }

     /**

      * Writes a portion of a String.

      *

      * <p> If the value of the <tt>len</tt> parameter is negative then no

      * characters are written.  This is contrary to the specification of this

      * method in the {@linkplain java.io.Writer#write(java.lang.String,int,int)

      * superclass}, which requires that an {@link IndexOutOfBoundsException} be

      * thrown.

      *

      * @param  s     String to be written

      * @param  off   Offset from which to start reading characters

      * @param  len   Number of characters to be written

      *

      * @exception  IOException  If an I/O error occurs

      */

     public void write(String s, int off, int len) throws IOException {

         synchronized (lock) {

             ensureOpen();

             int b = off, t = off + len;

             while (b < t) {

                 int d = min(nChars - nextChar, t - b);

                 s.getChars(b, b + d, cb, nextChar);

                 b += d;

                 nextChar += d;

                 if (nextChar >= nChars)

                     flushBuffer();

             }

         }

     }

     /**

      * Writes a line separator.  The line separator string is defined by the

      * system property <tt>line.separator</tt>, and is not necessarily a single

      * newline ('\n') character.

      *

      * @exception  IOException  If an I/O error occurs

      */

     public void newLine() throws IOException {

         write(lineSeparator);

     }

     /**

      * Flushes the stream.

      *

      * @exception  IOException  If an I/O error occurs

      */

     public void flush() throws IOException {

         synchronized (lock) {

             flushBuffer();

             out.flush();

         }

     }

     public void close() throws IOException {

         synchronized (lock) {

             if (out == null) {

                 return;

             }

             try {

                 flushBuffer();

             } finally {

                 out.close();

                 out = null;

                 cb = null;

             }

         }

     }

 }