JXResourceLoader


1   package com.ca.directory.jxplorer;
2   
3   import java.util.*;
4   import java.io.*;
5   import java.util.zip.ZipException  ;
6   import java.awt.Toolkit  ;
7   import java.awt.Image  ;
8   
9   import com.ca.commons.cbutil.*;
10  
11  /**
12   * This Class provides access to a group of zip files.  In the case of namespace conflicts between
13   * Zip files, the first zip file registered has priority.  The zip files are accessed through CBJarResource.
14   *
15   *
16   * @author Chris Betts
17   * @see com.ca.od.util.CBJarResource
18   */
19  
20  
21  public class JXResourceLoader
22  {
23      /**
24       * a cached list of 'unknown' resources that have been (unsuccessfully) looked up before.
25       */
26  
27      protected HashSet unknownResources = new HashSet();
28  
29      /**
30       * A list of CBJarResources objects that may be searched for packaged resources.
31       */
32  
33      protected CBJarResource[] resourceFiles = null;
34  
35      /**
36       * Whether to print out shtuff on the way.
37       */
38  
39      protected static boolean debug = false;
40  
41      /**
42       * Constructor - note that that the class is useless until at least one resource file has been
43       * registered with it using the addResource() method.
44       */
45  
46      public JXResourceLoader()
47      {
48          debug = (JXplorer.getProperty("debuglevel", "0").compareTo("7") >= 0);
49  
50          if (debug)
51              System.out.println("Started JXResourceLoader");
52      }
53  
54      /**
55       *  Adds a new zip/jar resource file to the list of files to be examined for resources.
56       */
57  
58      public void addResource(CBJarResource resource)
59      {
60          int size = (resourceFiles == null)?0:(resourceFiles.length);
61  
62          // The clumsiness of using an array is balanced by the need for quick
63          // access, and the fact that normally only a small number of resources are added,
64          // and only at the start of program operation.
65  
66          CBJarResource[] newArray = new CBJarResource[size+1];
67          for (int i=0; i<size; i++)
68              newArray[i] = resourceFiles[i];
69          newArray[size] = resource;
70          resourceFiles = newArray;
71  
72          if (debug)
73              System.out.println("Added CBJarResource: " + resource.toString());
74      }
75  
76      /**
77       *  Search all registered zip files for a particular file, and return an input stream to that
78       *  file.
79       */
80  
81      public InputStream getInputStream(String   resourceName) throws ZipException  
82      {
83          CBJarResource resourceFile = getJarContainingResource(resourceName);
84          if (resourceFile != null)
85              return resourceFile.getInputStream(resourceName);
86  
87          throw new ZipException  ("File: '" + resourceName + "' not found");
88      }
89  
90      /**
91       *  Search all registered zip files for a particular Image, and return an awt Image
92       *  object.
93       */
94  
95      public Image   getImage(String   imageName, Toolkit   imageCreator) throws ZipException  
96      {
97          CBJarResource resourceFile = getJarContainingResource(imageName);
98          if (resourceFile != null)
99              return resourceFile.getImage(imageName, imageCreator);
100 
101         throw new ZipException  ("Image File: '" + imageName + "' not found");
102     }
103 
104     /**
105      *  Search all registered zip files for a particular file, and return the data within that
106      *  file as a byte array.  (This might be used to initialise a String object if the file is
107      *  a text file, for instance.)
108      */
109 
110     public byte[] getResource(String   resourceName) throws ZipException  
111     {
112         CBJarResource resourceFile = getJarContainingResource(resourceName);
113         if (resourceFile != null)
114             return resourceFile.getResource(resourceName);
115 
116         throw new ZipException  ("File: '" + resourceName + "' not found");
117 
118     }
119 
120     /**
121      * Searches an internal hash, followed by all Jar files, for a particular resource.
122      */
123     protected CBJarResource getJarContainingResource(String   resourceName)
124     {
125         // check to see if we've already looked for this resource.
126         if (unknownResources.contains(resourceName)) return null;
127 
128         for (int i=0; i<resourceFiles.length; i++)
129             if (resourceFiles[i].hasResource(resourceName))
130                 return resourceFiles[i];
131 
132         // nothing found!  Add an entry to the unknownResources hashset so that we don't look for
133         // it again.
134 
135         unknownResources.add(resourceName);
136 
137         return null; // nothing found
138     }
139 
140     /**
141      *    Returns all resources with the given prefix.
142      *    @param prefix a string to match the start of resources against, e.g. 'icons/'
143      */
144     
145     public String  [] getPrefixedResources(String   prefix)
146     {
147         Vector resources = new Vector();
148 
149         // cycle through all resource files, gathering prefixed resources.
150         // name clashes are simply included twice :-)
151                 
152         for (int i=0; i<resourceFiles.length; i++)
153         {
154             resources.addAll(Arrays.asList(resourceFiles[i].getPrefixedResources(prefix)));
155         } 
156         
157         // cast stuff back to string for return.
158         if (resources.size() == 0)
159         {
160             return new String  [] {};
161         }        
162         else
163         {   
164             return (String  []) resources.toArray(new String  [resources.size()]);
165         }       
166     }
167 
168     /**
169      *    This is a very PRIMATIVE wildcard matching routine - it allows
170      *    only ONE wildcard, and that wildcard MUST be a '*' character.
171      *    (So in effect this is simply a prefix + suffix match).
172      *    @param exp a SIMPLE wildcard expression to match, e.g. 'templates/plain*.html'
173      */
174     
175     public String  [] getWildCardResources(String   exp)
176     {
177         int wildpos = exp.indexOf('*');
178         if (wildpos == -1) return new String  [] {exp};
179         
180         if (wildpos == exp.length()-1) // i.e. last character
181             return getPrefixedResources(exp.substring(0,exp.length()-1));
182             
183         String   prefix = exp.substring(0,wildpos);
184         String   suffix = exp.substring(wildpos+1);
185         
186 System.out.println("found prefix: " + prefix + " suffix " + suffix);        
187     
188         Vector resources = new Vector();
189 
190         // cycle through all resource files, gathering prefixed resources.
191         // name clashes are simply included twice :-)
192                 
193         for (int i=0; i<resourceFiles.length; i++)
194         {
195 //            resources.addAll(Arrays.asList(resourceFiles[i].getBoundedResources(prefix, suffix)));
196         } 
197         
198         // cast stuff back to string for return.
199         if (resources.size() == 0)
200         {
201             return new String  [] {};
202         }        
203         else
204         {   
205             return (String  []) resources.toArray(new String  [resources.size()]);
206         }        
207     }
208 
209 
210 
211 }
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