PUBLIC COMMENTS

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CONVERTED DATA

BugTraq+ Release Management Values

COMMIT TO FIX:
mantis
mantis-b02

FIXED IN:
mantis
mantis-b02

INTEGRATED IN:
mantis
mantis-b02

VERIFIED IN:
mantis


                                     

SUGGESTED FIX



Name: dsR10078			Date: 05/11/2002


Check for null elements when iterating over the supported data flavors.

###@###.### 2002-05-11
======================================================================

Name: agR10216			Date: 05/24/2002


To protect our code from nulls, returned by Transferable.getTransferDataFlavors(),
in addition to checking for null data flavors when iterating over them
we should handle null DataFlavor array.

--- DataTransferer.java Fri May 24 14:58:02 2002
***************
*** 667,673 ****
       */
      public Map getFormatsForTransferable(Transferable contents,
                                           FlavorTable map) {
!         return getFormatsForFlavors(contents.getTransferDataFlavors(), map);
      }

      /**
--- 667,677 ----
       */
      public Map getFormatsForTransferable(Transferable contents,
                                           FlavorTable map) {
!         DataFlavor[] flavors = contents.getTransferDataFlavors();
!         if (flavors == null) {
!             return new HashMap(0);
!         }
!         return getFormatsForFlavors(flavors, map);
      }

      /**
***************
*** 686,691 ****
--- 690,700 ----
       * in the specified DataFlavors can be translated. The value of each key
       * is the DataFlavor in which the Transferable's data should be requested
       * when converting to the format.
+      *
+      * @param flavors the data flavors
+      * @param map the FlavorTable which contains mappings between
+      *            DataFlavors and data formats
+      * @throws NullPointerException if flavors or map is <code>null</code>
       */
      public Map getFormatsForFlavors(DataFlavor[] flavors, FlavorTable map) {
          Map formatMap = new HashMap(flavors.length);
***************
*** 696,701 ****
--- 705,711 ----
          // Transferable.getTransferDataFlavors.)
          for (int i = flavors.length - 1; i >= 0; i--) {
              DataFlavor flavor = flavors[i];
+             if (flavor == null) continue;

              // Don't explicitly test for String, since it is just a special
              // case of Serializable

###@###.###  2002-05-24
======================================================================
                                     

EVALUATION



Name: dsR10078			Date: 05/11/2002


The NullPointerException is thrown because the imageFlavor field is
initialized after the supportedFlavors field. As a result the
supportedFlavors references an array that contains a null element.

This exception didn't manifest in 1.3 on Windows, because transfer of
non-textual data via the clipboard was not supported. In 1.4 the
clipboard support was enchanced, so that it is possible to transfer
data in various formats. The data transfer subsystem iterates over the
data flavors supported by the specified Transferable and operates on
them without check for null.

Strictly, the TransferableSample is incorrect, as
isDataFlavorSupported() returns true for the a non-null imageFlavor,
while getTransferDataFlavors() returns an array that contains a single
null element.

The test should be modified as follows:
------------------------------------------------------------------------
--- CBTest.java Sat May 11 14:15:41 2002
***************
*** 17,23 ****
  static public class TransferableSample implements Transferable, ClipboardOwner {
  
        public DataFlavor imageFlavor;
!       private DataFlavor [] supportedFlavors = {imageFlavor};
        private Image picture ;
  
        public TransferableSample () {
--- 17,23 ----
  static public class TransferableSample implements Transferable, ClipboardOwner {
  
        public DataFlavor imageFlavor;
!       private DataFlavor [] supportedFlavors;
        private Image picture ;
  
        public TransferableSample () {
***************
*** 31,36 ****
--- 31,38 ----
                        catch (ClassNotFoundException e) {
                        e.printStackTrace ();
                }
+ 
+                 supportedFlavors = new DataFlavor[] {imageFlavor};
        }
     
        public synchronized DataFlavor [] getTransferDataFlavors () {
------------------------------------------------------------------------

When the test is modified in this way, the exception is no longer
thrown. 

This test exposes a bug in the data transfer subsystem, since the
javadoc doesn't specify that Clipboard.setContents() throws NPE when
an array returned from the Transferable.getTransferDataFlavors()
contains a null element.

###@###.### 2002-05-11

======================================================================

Name: dsR10078			Date: 05/11/2002


With JDK 1.3, the test completes without an exception on Windows, but
on Solaris the test fails with exception: 

<das@horror(pts/17).406> /set/java/jdk1.3/solaris/bin/java -version
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, interpreted mode)
<das@horror(pts/17).407> /set/java/jdk1.3/solaris/bin/java CBTest
Exception in thread "main" java.lang.NullPointerException
        at sun.awt.motif.X11Selection.putDataInAllFlavors(X11Selection.java:177)
        at sun.awt.motif.X11Selection.getSelectionOwnership(X11Selection.java:201)
        at sun.awt.motif.X11Clipboard.setContents(X11Clipboard.java:41)
        at CBTest.main(CBTest.java:11)

###@###.### 2002-05-11

======================================================================