AbstractDefaultToStringRenderable xref

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1   /*
2    * $Id: AbstractDefaultToStringRenderable.java 791161 2009-07-04 18:53:36Z apetrelli $
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  
22  package org.apache.tiles.velocity.template;
23  
24  import java.io.IOException;
25  import java.io.StringWriter;
26  import java.util.Map;
27  
28  import javax.servlet.http.HttpServletRequest;
29  import javax.servlet.http.HttpServletResponse;
30  
31  import org.apache.tiles.velocity.TilesVelocityException;
32  import org.apache.velocity.context.Context;
33  import org.apache.velocity.exception.MethodInvocationException;
34  import org.apache.velocity.exception.ParseErrorException;
35  import org.apache.velocity.exception.ResourceNotFoundException;
36  import org.apache.velocity.runtime.Renderable;
37  import org.slf4j.Logger;
38  import org.slf4j.LoggerFactory;
39  
40  /***
41   * Renderable that provides a default implementation of {@link Renderable#toString()}
42   * and allows access to parameters and context objects.
43   *
44   * @version $Rev: 791161 $ $Date: 2009-07-04 20:53:36 +0200 (sab, 04 lug 2009) $
45   * @since 2.2.0
46   */
47  public abstract class AbstractDefaultToStringRenderable implements Renderable {
48  
49  
50      /***
51       * The Velocity context.
52       *
53       * @since 2.2.0
54       */
55      protected final Context velocityContext;
56  
57      /***
58       * The parameters used in the current tool call.
59       *
60       * @since 2.2.0
61       */
62      protected final Map<String, Object> params;
63  
64      /***
65       * The HTTP response.
66       *
67       * @since 2.2.0
68       */
69      protected final HttpServletResponse response;
70  
71      /***
72       * The HTTP request.
73       *
74       * @since 2.2.0
75       */
76      protected final HttpServletRequest request;
77  
78      /***
79       * The logging object.
80       */
81      private final Logger log = LoggerFactory.getLogger(getClass());
82  
83      /***
84       * Constructor.
85       *
86       * @param velocityContext The Velocity context.
87       * @param params The parameters used in the current tool call.
88       * @param response The HTTP response.
89       * @param request The HTTP request.
90       * @since 2.2.0
91       */
92      public AbstractDefaultToStringRenderable(Context velocityContext,
93              Map<String, Object> params, HttpServletResponse response,
94              HttpServletRequest request) {
95          this.velocityContext = velocityContext;
96          this.params = params;
97          this.response = response;
98          this.request = request;
99      }
100 
101     /*** {@inheritDoc} */
102     @Override
103     public String toString() {
104         StringWriter writer = new StringWriter();
105         try {
106             render(null, writer);
107         } catch (MethodInvocationException e) {
108             throw new TilesVelocityException("Cannot invoke method when rendering", e);
109         } catch (ParseErrorException e) {
110             throw new TilesVelocityException("Cannot parse when rendering", e);
111         } catch (ResourceNotFoundException e) {
112             throw new TilesVelocityException("Cannot find resource when rendering", e);
113         } catch (IOException e) {
114             throw new TilesVelocityException("I/O exception when rendering", e);
115         } finally {
116             try {
117                 writer.close();
118             } catch (IOException e) {
119                 log.error("Error when closing a StringWriter, the impossible happened!", e);
120             }
121         }
122         return writer.toString();
123     }
124 }