content: /*
   * Copyright (c) 1996, 2013, 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 {@code sz <= 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 Writer#write(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();
          }
      }
  
      @SuppressWarnings("try")
      public void close() throws IOException {
          synchronized (lock) {
              if (out == null) {
                  return;
              }
              try (Writer w = out) {
                  flushBuffer();
              } finally {
                  out = null;
                  cb = null;
              }
          }
      }
  }
  