ResourceImageReference


1   /* 
2    * This file is part of the Echo Web Application Framework (hereinafter "Echo").
3    * Copyright (C) 2002-2005 NextApp, Inc.
4    *
5    * Version: MPL 1.1/GPL 2.0/LGPL 2.1
6    *
7    * The contents of this file are subject to the Mozilla Public License Version
8    * 1.1 (the "License"); you may not use this file except in compliance with
9    * the License. You may obtain a copy of the License at
10   * http://www.mozilla.org/MPL/
11   *
12   * Software distributed under the License is distributed on an "AS IS" basis,
13   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
14   * for the specific language governing rights and limitations under the
15   * License.
16   *
17   * Alternatively, the contents of this file may be used under the terms of
18   * either the GNU General Public License Version 2 or later (the "GPL"), or
19   * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
20   * in which case the provisions of the GPL or the LGPL are applicable instead
21   * of those above. If you wish to allow use of your version of this file only
22   * under the terms of either the GPL or the LGPL, and not to allow others to
23   * use your version of this file under the terms of the MPL, indicate your
24   * decision by deleting the provisions above and replace them with the notice
25   * and other provisions required by the GPL or the LGPL. If you do not delete
26   * the provisions above, a recipient may use your version of this file under
27   * the terms of any one of the MPL, the GPL or the LGPL.
28   */
29  
30  package nextapp.echo2.app;
31  
32  import java.io.IOException  ;
33  import java.io.InputStream  ;
34  import java.io.OutputStream  ;
35  import java.util.Collections  ;
36  import java.util.HashMap  ;
37  import java.util.Map  ;
38  
39  /**
40   * A representation of an image that will be retrieved as a resource from 
41   * the CLASSPATH.
42   */
43  public class ResourceImageReference
44  extends StreamImageReference {
45      
46      /**
47       * Size of buffer used for reading image data from CLASSPATH and writing
48       * it to <code>OutputStream</code>s.
49       */
50      private static final int BUFFER_SIZE = 4096;
51      
52      /**
53       * Mapping of extensions to content types.
54       */
55      private static final Map   extensionToContentType;
56      static {
57          Map   map = new HashMap  ();
58          map.put("gif",  "image/gif");
59          map.put("png",  "image/png");
60          map.put("jpeg", "image/jpeg");
61          map.put("jpg",  "image/jpg");
62          map.put("bmp",  "image/bmp");
63          extensionToContentType = Collections.unmodifiableMap(map);
64      }
65      
66      /**
67       * Automatically determines the content type based on the name of a 
68       * resource.
69       * 
70       * @param resourceName the resource name
71       * @return the discovered content type
72       * @throws IllegalArgumentException if no content type can be determined
73       */
74      private static final String   getContentType(String   resourceName) {
75          String   contentType;
76      
77          // Determine content type.
78          int extensionDelimiterPosition = resourceName.lastIndexOf(".");
79          if (extensionDelimiterPosition == -1) {
80              throw new IllegalArgumentException  ("Invalid file extension (resource has no extension: " + resourceName + ")");
81          } else {
82              String   extension = resourceName.substring(extensionDelimiterPosition + 1).toLowerCase();
83              contentType = (String  ) extensionToContentType.get(extension);
84              if (contentType == null) {
85                  throw new IllegalArgumentException  ("Invalid file extension (no matching content type: " + resourceName + ")");
86              }
87          }
88          
89          return contentType;
90      }
91  
92      private Extent width, height;
93      private String   contentType;
94      private String   resource;
95      private String   id;
96      
97      /**
98       * Creates a <code>ResourceImageReference</code>.
99       * The content type will be automatically determined.
100      * 
101      * @param resource the resource name containing the binary image data
102      */
103     public ResourceImageReference(String   resource) {
104         this(resource, null, null, null);
105     }
106     
107     /**
108      * Creates a <code>ResourceImageReference</code>.
109      * 
110      * @param resource the resource name containing the binary image data
111      *        (all resource names will be treated as absolute, it is 
112      *        unnecessary to prepend a leading slash to the resource name)
113      * @param contentType the content type of the image (or null to 
114      *        automatically determine the content type based on the resource
115      *        extension)
116      */
117     public ResourceImageReference(String   resource, String   contentType) {
118         this(resource, contentType, null, null);
119     }
120 
121     /**
122      * Creates a <code>ResourceImageReference</code>.
123      * The content type will be automatically determined.
124      * 
125      * @param resource the resource name containing the binary image data
126      *        (all resource names will be treated as absolute, it is 
127      *        unnecessary to prepend a leading slash to the resource name)
128      * @param width the width of the image
129      * @param height the height of the image
130      */
131     public ResourceImageReference(String   resource, Extent width, Extent height) {
132         this(resource, null, width, height);
133     }
134 
135     /**
136      * Creates a <code>ResourceImageReference</code>.
137      * 
138      * @param resource the resource name containing the binary image data
139      *        (all resource names will be treated as absolute, it is 
140      *        unnecessary to prepend a leading slash to the resource name)
141      * @param contentType the content type of the image (or null to 
142      *        automatically determine the content type based on the resource
143      *        extension)
144      * @param width the width of the image
145      * @param height the height of the image
146      */
147     public ResourceImageReference(String   resource, String   contentType, Extent width, Extent height) {
148         super();
149         
150         // Drop leading slash as all resource paths are absolute.
151         if (resource.charAt(0) == '/') {
152             this.resource = resource.substring(1);
153         } else {
154             this.resource = resource;
155         }
156         
157         this.contentType = contentType == null ? getContentType(resource) : contentType;
158         this.width = width;
159         this.height = height;
160         id = ApplicationInstance.generateSystemId();
161     }
162     
163     /**
164      * @see java.lang.Object#equals(java.lang.Object)
165      */
166     public boolean equals(Object   o) {
167         if (!(o instanceof ResourceImageReference)) {
168             return false;
169         }
170         ResourceImageReference that = (ResourceImageReference) o;
171         if (!(this.resource == that.resource || (this.resource != null && this.resource.equals(that.resource)))) {
172             return false;
173         }
174         if (!(this.contentType == that.contentType || (this.contentType != null && this.contentType.equals(that.contentType)))) {
175             return false;
176         }
177         if (!(this.width == that.width || (this.width != null && this.width.equals(that.width)))) {
178             return false;
179         }
180         if (!(this.height == that.height || (this.height != null && this.height.equals(that.height)))) {
181             return false;
182         }
183         return true;
184     }
185     
186     /**
187      * @see nextapp.echo2.app.StreamImageReference#getContentType()
188      */
189     public String   getContentType() {
190         return contentType;
191     }
192 
193     /**
194      * @see nextapp.echo2.app.ImageReference#getHeight()
195      */
196     public Extent getHeight() {
197         return height;
198     }
199 
200     /**
201      * @see nextapp.echo2.app.RenderIdSupport#getRenderId()
202      */
203     public String   getRenderId() {
204         return id;
205     }
206     
207     /**
208      * Returns the name of the resource.
209      * 
210      * @return the name of the resource
211      */
212     public String   getResource() {
213         return resource;
214     }
215     
216     /**
217      * @see nextapp.echo2.app.ImageReference#getWidth()
218      */
219     public Extent getWidth() {
220         return width;
221     }
222 
223     /**
224      * @see java.lang.Object#hashCode()
225      */
226     public int hashCode() {
227         return resource == null ? 0 : resource.hashCode();
228     }
229 
230     /**
231      * @see nextapp.echo2.app.StreamImageReference#render(java.io.OutputStream)
232      */
233     public void render(OutputStream   out) 
234     throws IOException   {
235         InputStream   in = null;
236         byte[] buffer = new byte[BUFFER_SIZE];
237         int bytesRead = 0;
238         
239         try {
240             in = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
241             if (in == null) {
242                 throw new IllegalArgumentException  ("Specified resource does not exist: " + resource + ".");
243             }
244             do {
245                 bytesRead = in.read(buffer);
246                 if (bytesRead > 0) {
247                     out.write(buffer, 0, bytesRead);
248                 }
249             } while (bytesRead > 0);
250         } finally {
251             if (in != null) { try { in.close(); } catch (IOException   ex) { } } 
252         }
253     }
254 }
255
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