BasicTransferable


1   /*
2    * @(#)BasicTransferable.java   1.9 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   package javax.swing.plaf.basic;
8   
9   import java.io.*;
10  import java.awt.datatransfer.*;
11  import javax.swing.plaf.UIResource  ;
12  
13  /**
14   * A transferable implementation for the default data transfer of some Swing
15   * components.  
16   *
17   * @author  Timothy Prinzing
18   * @version 1.9 12/19/03
19   */
20  class BasicTransferable implements Transferable, UIResource   {
21      
22      protected String   plainData;
23      protected String   htmlData;
24  
25      private static DataFlavor[] htmlFlavors;
26      private static DataFlavor[] stringFlavors;
27      private static DataFlavor[] plainFlavors;
28  
29      static {
30      try {
31          htmlFlavors = new DataFlavor[3];
32          htmlFlavors[0] = new DataFlavor("text/html;class=java.lang.String");
33          htmlFlavors[1] = new DataFlavor("text/html;class=java.io.Reader");
34          htmlFlavors[2] = new DataFlavor("text/html;charset=unicode;class=java.io.InputStream");
35  
36          plainFlavors = new DataFlavor[3];
37          plainFlavors[0] = new DataFlavor("text/plain;class=java.lang.String");
38          plainFlavors[1] = new DataFlavor("text/plain;class=java.io.Reader");
39          plainFlavors[2] = new DataFlavor("text/plain;charset=unicode;class=java.io.InputStream");
40  
41          stringFlavors = new DataFlavor[2];
42              stringFlavors[0] = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType+";class=java.lang.String");
43          stringFlavors[1] = DataFlavor.stringFlavor;
44   
45      } catch (ClassNotFoundException   cle) {
46          System.err.println("error initializing javax.swing.plaf.basic.BasicTranserable");
47      }
48      }
49      
50      public BasicTransferable(String   plainData, String   htmlData) {
51      this.plainData = plainData;
52      this.htmlData = htmlData;
53      }
54  
55  
56      /**
57       * Returns an array of DataFlavor objects indicating the flavors the data 
58       * can be provided in.  The array should be ordered according to preference
59       * for providing the data (from most richly descriptive to least descriptive).
60       * @return an array of data flavors in which this data can be transferred
61       */
62      public DataFlavor[] getTransferDataFlavors() {
63      DataFlavor[] richerFlavors = getRicherFlavors();
64      int nRicher = (richerFlavors != null) ? richerFlavors.length : 0;
65      int nHTML = (isHTMLSupported()) ? htmlFlavors.length : 0;
66      int nPlain = (isPlainSupported()) ? plainFlavors.length: 0;
67      int nString = (isPlainSupported()) ? stringFlavors.length : 0;
68      int nFlavors = nRicher + nHTML + nPlain + nString;
69      DataFlavor[] flavors = new DataFlavor[nFlavors];
70      
71      // fill in the array
72      int nDone = 0;
73      if (nRicher > 0) {
74          System.arraycopy(richerFlavors, 0, flavors, nDone, nRicher);
75          nDone += nRicher;
76      }
77      if (nHTML > 0) {
78          System.arraycopy(htmlFlavors, 0, flavors, nDone, nHTML);
79          nDone += nHTML;
80      }
81      if (nPlain > 0) {
82          System.arraycopy(plainFlavors, 0, flavors, nDone, nPlain);
83          nDone += nPlain;
84      }
85      if (nString > 0) {
86          System.arraycopy(stringFlavors, 0, flavors, nDone, nString);
87          nDone += nString;
88      }
89      return flavors;
90      }
91  
92      /**
93       * Returns whether or not the specified data flavor is supported for
94       * this object.
95       * @param flavor the requested flavor for the data
96       * @return boolean indicating whether or not the data flavor is supported
97       */
98      public boolean isDataFlavorSupported(DataFlavor flavor) {
99      DataFlavor[] flavors = getTransferDataFlavors();
100         for (int i = 0; i < flavors.length; i++) {
101         if (flavors[i].equals(flavor)) {
102             return true;
103         }
104     }
105     return false;
106     }
107 
108     /**
109      * Returns an object which represents the data to be transferred.  The class 
110      * of the object returned is defined by the representation class of the flavor.
111      *
112      * @param flavor the requested flavor for the data
113      * @see DataFlavor#getRepresentationClass
114      * @exception IOException                if the data is no longer available
115      *              in the requested flavor.
116      * @exception UnsupportedFlavorException if the requested data flavor is
117      *              not supported.
118      */
119     public Object   getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
120     DataFlavor[] richerFlavors = getRicherFlavors();
121     if (isRicherFlavor(flavor)) {
122         return getRicherData(flavor);
123     } else if (isHTMLFlavor(flavor)) {
124         String   data = getHTMLData();
125         data = (data == null) ? "" : data;
126         if (String  .class.equals(flavor.getRepresentationClass())) {
127         return data;
128         } else if (Reader.class.equals(flavor.getRepresentationClass())) {
129         return new StringReader(data);
130         } else if (InputStream.class.equals(flavor.getRepresentationClass())) {
131         return new StringBufferInputStream(data);
132         }
133         // fall through to unsupported
134     } else if (isPlainFlavor(flavor)) {
135         String   data = getPlainData();
136         data = (data == null) ? "" : data;
137         if (String  .class.equals(flavor.getRepresentationClass())) {
138         return data;
139         } else if (Reader.class.equals(flavor.getRepresentationClass())) {
140         return new StringReader(data);
141         } else if (InputStream.class.equals(flavor.getRepresentationClass())) {
142         return new StringBufferInputStream(data);
143         }
144         // fall through to unsupported
145 
146     } else if (isStringFlavor(flavor)) {
147         String   data = getPlainData();
148         data = (data == null) ? "" : data;
149         return data;
150     }
151     throw new UnsupportedFlavorException(flavor);
152     }
153 
154     // --- richer subclass flavors ----------------------------------------------
155 
156     protected boolean isRicherFlavor(DataFlavor flavor) {
157     DataFlavor[] richerFlavors = getRicherFlavors();
158     int nFlavors = (richerFlavors != null) ? richerFlavors.length : 0;
159     for (int i = 0; i < nFlavors; i++) {
160         if (richerFlavors[i].equals(flavor)) {
161         return true;
162         }
163     }
164     return false;
165     }
166     
167     /** 
168      * Some subclasses will have flavors that are more descriptive than HTML
169      * or plain text.  If this method returns a non-null value, it will be
170      * placed at the start of the array of supported flavors.
171      */
172     protected DataFlavor[] getRicherFlavors() {
173     return null;
174     }
175 
176     protected Object   getRicherData(DataFlavor flavor) throws UnsupportedFlavorException {
177     return null;
178     }
179 
180     // --- html flavors ----------------------------------------------------------
181 
182     /**
183      * Returns whether or not the specified data flavor is an HTML flavor that
184      * is supported.
185      * @param flavor the requested flavor for the data
186      * @return boolean indicating whether or not the data flavor is supported
187      */
188     protected boolean isHTMLFlavor(DataFlavor flavor) {
189     DataFlavor[] flavors = htmlFlavors;
190         for (int i = 0; i < flavors.length; i++) {
191         if (flavors[i].equals(flavor)) {
192             return true;
193         }
194     }
195     return false;
196     }
197 
198     /**
199      * Should the HTML flavors be offered?  If so, the method
200      * getHTMLData should be implemented to provide something reasonable.
201      */
202     protected boolean isHTMLSupported() {
203     return htmlData != null;
204     }
205 
206     /**
207      * Fetch the data in a text/html format
208      */
209     protected String   getHTMLData() {
210     return htmlData;
211     }
212 
213     // --- plain text flavors ----------------------------------------------------
214 
215     /**
216      * Returns whether or not the specified data flavor is an plain flavor that
217      * is supported.
218      * @param flavor the requested flavor for the data
219      * @return boolean indicating whether or not the data flavor is supported
220      */
221     protected boolean isPlainFlavor(DataFlavor flavor) {
222     DataFlavor[] flavors = plainFlavors;
223         for (int i = 0; i < flavors.length; i++) {
224         if (flavors[i].equals(flavor)) {
225             return true;
226         }
227     }
228     return false;
229     }
230 
231     /**
232      * Should the plain text flavors be offered?  If so, the method
233      * getPlainData should be implemented to provide something reasonable.
234      */
235     protected boolean isPlainSupported() {
236     return plainData != null;
237     }
238 
239     /**
240      * Fetch the data in a text/plain format.
241      */
242     protected String   getPlainData() {
243     return plainData;
244     }
245 
246     // --- string flavorss --------------------------------------------------------
247 
248     /**
249      * Returns whether or not the specified data flavor is a String flavor that
250      * is supported.
251      * @param flavor the requested flavor for the data
252      * @return boolean indicating whether or not the data flavor is supported
253      */
254     protected boolean isStringFlavor(DataFlavor flavor) {
255     DataFlavor[] flavors = stringFlavors;
256         for (int i = 0; i < flavors.length; i++) {
257         if (flavors[i].equals(flavor)) {
258             return true;
259         }
260     }
261     return false;
262     }
263 
264 
265 }
266
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