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1   /*
2    * $Source$
3    * $Revision$
4    *
5    * Copyright (C) 2000 Tim Joyce
6    *
7    * Part of Melati (http://melati.org), a framework for the rapid
8    * development of clean, maintainable web applications.
9    *
10   * Melati is free software; Permission is granted to copy, distribute
11   * and/or modify this software under the terms either:
12   *
13   * a) the GNU General Public License as published by the Free Software
14   *    Foundation; either version 2 of the License, or (at your option)
15   *    any later version,
16   *
17   *    or
18   *
19   * b) any version of the Melati Software License, as published
20   *    at http://melati.org
21   *
22   * You should have received a copy of the GNU General Public License and
23   * the Melati Software License along with this program;
24   * if not, write to the Free Software Foundation, Inc.,
25   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26   * GNU General Public License and visit http://melati.org to obtain the
27   * Melati Software License.
28   *
29   * Feel free to contact the Developers of Melati (http://melati.org),
30   * if you would like to work out a different arrangement than the options
31   * outlined here.  It is our intention to allow Melati to be used by as
32   * wide an audience as possible.
33   *
34   * This program is distributed in the hope that it will be useful,
35   * but WITHOUT ANY WARRANTY; without even the implied warranty of
36   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
37   * GNU General Public License for more details.
38   *
39   * Contact details for copyright holder:
40   *
41   *     Tim Joyce <timj At paneris.org>
42   */
43  
44  package org.melati.template.velocity;
45  
46  import java.io.ByteArrayOutputStream;
47  import java.io.IOException;
48  import java.io.OutputStream;
49  
50  import javax.servlet.http.HttpServletResponse;
51  
52  /**
53   * Provides an interface for objects that output from melati.
54   */
55  
56  public class MelatiBufferedVelocityWriter extends MelatiVelocityWriter {
57  
58    private OutputStream underlying;
59    private ByteArrayOutputStream buffer;
60  
61    /**
62     * Constructor.
63     * @param output OutputStream to write to
64     * @param encoding character encoding to use 
65     */
66    public MelatiBufferedVelocityWriter(OutputStream output, 
67                                       String encoding)
68        throws IOException {
69      super(new ByteArrayOutputStream(), encoding);
70      buffer = (ByteArrayOutputStream)outputStream;
71      underlying = output;
72    }
73  
74    /**
75     * Constructor.
76     * @param response from which to get OutputSteram and encoding
77     * @throws IOException
78     */
79    public MelatiBufferedVelocityWriter(HttpServletResponse response) 
80        throws IOException {
81      this(response.getOutputStream(), response.getCharacterEncoding());
82    }
83    
84  
85    /**
86     * @see org.melati.template.velocity.MelatiVelocityWriter#close()
87     */
88    public void close() throws IOException {
89      super.close();
90      try { 
91        buffer.writeTo(underlying);
92      } catch (IOException e) { 
93        e = null;
94      }
95      buffer.close(); 
96      underlying.flush();
97      underlying.close();
98    }
99    
100   /**
101    * @see org.melati.util.MelatiWriter#flush()
102    */
103   public void flush() throws IOException {
104     out.flush();
105     buffer.writeTo(underlying);
106     buffer.reset(); 
107     underlying.flush();
108   }  
109 
110   /**
111    * {@inheritDoc}
112    * @see org.melati.util.MelatiWriter#reset()
113    */
114   public void reset() throws IOException {
115     out.flush();
116     buffer.reset();
117   }
118 
119 }