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.OutputStream;
47 import java.io.OutputStreamWriter;
48 import java.io.IOException;
49 import java.io.UnsupportedEncodingException;
50
51 import javax.servlet.http.HttpServletResponse;
52
53 import org.melati.template.TemplateIOException;
54 import org.melati.util.MelatiWriter;
55
56 import org.apache.velocity.io.VelocityWriter;
57 import org.apache.velocity.util.SimplePool;
58
59 /**
60 * This provides an interface for objects that output from melati.
61 */
62 public class MelatiVelocityWriter extends MelatiWriter {
63
64 private static SimplePool writerPool = new SimplePool(40);
65 protected OutputStream outputStream;
66
67 /**
68 * Constructor.
69 * @param response the response to write to
70 * @throws IOException if getOutputStream throws one
71 */
72 public MelatiVelocityWriter(HttpServletResponse response)
73 throws IOException {
74 this(response.getOutputStream(), response.getCharacterEncoding());
75 }
76
77 /**
78 * Constructor.
79 * @param output OutputStream to write to
80 * @param encoding character encoding to use
81 */
82 public MelatiVelocityWriter(OutputStream output, String encoding) {
83 // need to make this accessible to subclasses
84 outputStream = output;
85 out = (VelocityWriter)writerPool.get();
86 if (out == null) {
87 try {
88 out = new VelocityWriter(new OutputStreamWriter(output, encoding),
89 4 * 1024, true);
90 } catch (UnsupportedEncodingException e) {
91 throw new TemplateIOException(e);
92 }
93 } else {
94 try {
95 ((VelocityWriter)out).recycle(new OutputStreamWriter(output, encoding));
96 } catch (UnsupportedEncodingException e) {
97 throw new TemplateIOException(e);
98 }
99 }
100 }
101
102 /**
103 * As we can write to the underlying peer the Flusher may not
104 * get started so we should start it here.
105 * @return the underlying output
106 */
107 public VelocityWriter getVelocityWriter() {
108 startFlushing();
109 return (VelocityWriter)out;
110 }
111
112 /**
113 * {@inheritDoc}
114 * @see java.io.Closeable#close()
115 */
116 public void close()
117 throws IOException {
118 super.close();
119 writerPool.put(getVelocityWriter());
120 }
121
122 }