Re: [Swig-user] Java class implements Comparable<ClssName>

[EXT-Harris, S. H <Sco...@bo...>]

Answering my own post:

---- from the SWIG interfacd file
...
// this line added "implements Comparable<X>" to the Java class declaration
%typemap(javainterfaces)       SWIGTYPE "Comparable<X>"
class IRTime {
public:
...

Change the generated Java class from:
  class IRTime {
to
  class IRTime implements Comparable<X>

What is a bit confusing is that the SWIG documentation says:
%typemap(javainterfaces)
             interfaces (extends) for Java class: empty default

but using '%typemap(javainterfaces)       SWIGTYPE "Comparable<X>"' results in "implements  Name" instead of "extends Name".
Should the "(extends)" be replaced with "(implements)" or is SWIG figuring out that Comparable is an interface (not a class) and hence it would insert "implements" vs "extends"?

Regards,
  Scott

From: EXT-Harris, Scott H
Sent: Saturday, October 08, 2011 5:10 PM
To: swi...@li...
Cc: EXT-Harris, Scott H
Subject: Java class implements Comparable<ClssName>

Hi,

How can I get SWIG to generate a java class that "implements Comparable"?

Let's say I have a C++ class X and an SWIG interface X that generates a compareTo(X rhs) method.

If I use the Java class generated by SWIG in a TreeMap then the second put will throw this exception:
CREATION exception: java.lang.ClassCastException: com.myCompany.project.X
in exception handler got exception: java.lang.NullPointerException

But if I modify the generated X.java file from
   public class X {
to
  public class X implements Comparable<X> {
then the exception is not thrown and the compareTo function is used as expected.

Can I get SWIG to add "implements Comparable<X> to the class?

FYI: For example of the test code:
X first = new X(1);
X last = new X(9);
TreeMap<X, String>mm = new TreeMap<X, String>();
String old = mm.put(last, "last");
// this next line throws the exeption
old = mm.put(first, "first");


Thanks,
  Scott