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1   /*
2    * $Id: CallbackWriter.java 471756 2006-11-06 15:01:43Z husted $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.struts2.views.freemarker.tags;
22  
23  import java.io.IOException;
24  import java.io.StringWriter;
25  import java.io.Writer;
26  
27  import org.apache.struts2.components.Component;
28  
29  import freemarker.template.TemplateModelException;
30  import freemarker.template.TransformControl;
31  
32  /***
33   */
34  public class CallbackWriter extends Writer implements TransformControl {
35      private Component bean;
36      private Writer writer;
37      private StringWriter body;
38      private boolean afterBody = false;
39  
40      public CallbackWriter(Component bean, Writer writer) {
41          this.bean = bean;
42          this.writer = writer;
43  
44          if (bean.usesBody()) {
45              this.body = new StringWriter();
46          }
47      }
48  
49      public void close() throws IOException {
50          if (bean.usesBody()) {
51              body.close();
52          }
53      }
54  
55      public void flush() throws IOException {
56          writer.flush();
57  
58          if (bean.usesBody()) {
59              body.flush();
60          }
61      }
62  
63      public void write(char cbuf[], int off, int len) throws IOException {
64          if (bean.usesBody() && !afterBody) {
65              body.write(cbuf, off, len);
66          } else {
67              writer.write(cbuf, off, len);
68          }
69      }
70  
71      public int onStart() throws TemplateModelException, IOException {
72          boolean result = bean.start(this);
73  
74          if (result) {
75              return EVALUATE_BODY;
76          } else {
77              return SKIP_BODY;
78          }
79      }
80  
81      public int afterBody() throws TemplateModelException, IOException {
82          afterBody = true;
83          boolean result = bean.end(this, bean.usesBody() ? body.toString() : "");
84  
85          if (result) {
86              return REPEAT_EVALUATION;
87          } else {
88              return END_EVALUATION;
89          }
90      }
91  
92      public void onError(Throwable throwable) throws Throwable {
93          throw throwable;
94      }
95  
96      public Component getBean() {
97          return bean;
98      }
99  }