Source for org.jfree.report.util.MemoryStringWriter

   1: /**
   2:  * ========================================
   3:  * JFreeReport : a free Java report library
   4:  * ========================================
   5:  *
   6:  * Project Info:  http://reporting.pentaho.org/
   7:  *
   8:  * (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
   9:  *
  10:  * This library is free software; you can redistribute it and/or modify it under the terms
  11:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
  12:  * either version 2.1 of the License, or (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  15:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16:  * See the GNU Lesser General Public License for more details.
  17:  *
  18:  * You should have received a copy of the GNU Lesser General Public License along with this
  19:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20:  * Boston, MA 02111-1307, USA.
  21:  *
  22:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  23:  * in the United States and other countries.]
  24:  *
  25:  * ------------
  26:  * $Id: MemoryStringWriter.java 3525 2007-10-16 11:43:48Z tmorgner $
  27:  * ------------
  28:  * (C) Copyright 2000-2005, by Object Refinery Limited.
  29:  * (C) Copyright 2005-2007, by Pentaho Corporation.
  30:  */
  31: 
  32: package org.jfree.report.util;
  33: 
  34: import java.io.IOException;
  35: import java.io.Writer;
  36: 
  37: /**
  38:  * A string writer that is able to write large amounts of data. The original StringWriter contained in Java doubles
  39:  * its buffersize everytime the buffer overflows. This is nice with small amounts of data, but awfull for huge
  40:  * buffers.
  41:  *
  42:  * @author Thomas Morgner
  43:  */
  44: public class MemoryStringWriter extends Writer
  45: {
  46:   private int bufferIncrement;
  47:   private int cursor;
  48:   private char[] buffer;
  49: 
  50:   /**
  51:    * Create a new character-stream writer whose critical sections will synchronize on the writer itself.
  52:    */
  53:   public MemoryStringWriter()
  54:   {
  55:     this(4096);
  56:   }
  57: 
  58:   /**
  59:    * Create a new character-stream writer whose critical sections will synchronize on the writer itself.
  60:    */
  61:   public MemoryStringWriter(final int bufferSize)
  62:   {
  63:     this.bufferIncrement = bufferSize;
  64:     this.buffer = new char[bufferSize];
  65:   }
  66: 
  67:   /**
  68:    * Write a portion of an array of characters.
  69:    *
  70:    * @param cbuf Array of characters
  71:    * @param off  Offset from which to start writing characters
  72:    * @param len  Number of characters to write
  73:    * @throws java.io.IOException If an I/O error occurs
  74:    */
  75:   public synchronized void write(final char[] cbuf, final int off, final int len) throws IOException
  76:   {
  77:     if (len < 0)
  78:     {
  79:       throw new IllegalArgumentException();
  80:     }
  81:     if (off < 0)
  82:     {
  83:       throw new IndexOutOfBoundsException();
  84:     }
  85:     if (cbuf == null)
  86:     {
  87:       throw new NullPointerException();
  88:     }
  89:     if ((len + off) > cbuf.length)
  90:     {
  91:       throw new IndexOutOfBoundsException();
  92:     }
  93: 
  94:     ensureSize (cursor + len);
  95: 
  96:     System.arraycopy(cbuf, off, this.buffer, cursor, len);
  97:     cursor += len;
  98:   }
  99: 
 100:   private void ensureSize(final int size)
 101:   {
 102:     if (this.buffer.length >= size)
 103:     {
 104:       return;
 105:     }
 106: 
 107:     final int newSize = Math.max (size, this.buffer.length + bufferIncrement);
 108:     final char[] newBuffer = new char[newSize];
 109:     System.arraycopy(this.buffer, 0, newBuffer, 0, cursor);
 110:   }
 111: 
 112:   /**
 113:    * Flush the stream.  If the stream has saved any characters from the various write() methods in a buffer, write them
 114:    * immediately to their intended destination.  Then, if that destination is another character or byte stream, flush
 115:    * it.  Thus one flush() invocation will flush all the buffers in a chain of Writers and OutputStreams.
 116:    * <p/>
 117:    * If the intended destination of this stream is an abstraction provided by the underlying operating system, for
 118:    * example a file, then flushing the stream guarantees only that bytes previously written to the stream are passed to
 119:    * the operating system for writing; it does not guarantee that they are actually written to a physical device such as
 120:    * a disk drive.
 121:    *
 122:    * @throws java.io.IOException If an I/O error occurs
 123:    */
 124:   public void flush() throws IOException
 125:   {
 126: 
 127:   }
 128: 
 129:   /**
 130:    * Close the stream, flushing it first.  Once a stream has been closed, further write() or flush() invocations will
 131:    * cause an IOException to be thrown.  Closing a previously-closed stream, however, has no effect.
 132:    *
 133:    * @throws java.io.IOException If an I/O error occurs
 134:    */
 135:   public void close() throws IOException
 136:   {
 137:   }
 138: 
 139:   public String toString ()
 140:   {
 141:     return new String (buffer, 0, cursor);
 142:   }
 143: }