Re: [Swig-user] %delobject and Java

[Bob M. <rma...@ee...>]

William S Fulton wrote:
> Bob Marinier wrote:
>   
>> I recently discovered a case in our code where it looks like we need to 
>> use %delobject on one of our methods.  However, there does not appear to 
>> be any change in the generated C++ or Java code (indeed, things still 
>> crash for us).  Is %delobject implemented for Java?
>>
>> Just to see if, in principle, this change would work, we hand-modified 
>> the generated Java code to set swigCMemOwn flag of the parameter to the 
>> method to false, and this does indeed fix our problem.  If %delobject is 
>> not implemented for Java, is there a way to automatically insert this 
>> code in the beginning of the generated Java code for this method?  I 
>> suppose I could rename the generated method and create a wrapper method 
>> with the original name that sets this flag and then calls the renamed 
>> method, but being able to insert code directly into the generated Java 
>> would be cleaner.
>>
>>     
>
> There is no DISOWN typemap for Java, so %delobject won't work as it
> requires these typemaps. Instead you can modify the code through the
> javain typemap. See the documentation in Java.html about memory
> management, there are some examples too.
>
> William
>   

I'm not sure I follow.  I have a function in C++ that looks like this:

ElementXML_Handle ElementXML::AddChild(ElementXML* pChild);

The generated Java code looks like this:

public SWIGTYPE_p_ElementXML_InterfaceStructTag AddChild(ElementXML 
pChild) {
    long cPtr = smlJNI.ElementXML_AddChild(swigCPtr, this, 
ElementXML.getCPtr(pChild), pChild);
    return (cPtr == 0) ? null : new 
SWIGTYPE_p_ElementXML_InterfaceStructTag(cPtr, false);
  }

...but I want it to look like this:

public SWIGTYPE_p_ElementXML_InterfaceStructTag AddChild(ElementXML 
pChild) {
    pChild.swigCMemOwn = false;
    long cPtr = smlJNI.ElementXML_AddChild(swigCPtr, this, 
ElementXML.getCPtr(pChild), pChild);
    return (cPtr == 0) ? null : new 
SWIGTYPE_p_ElementXML_InterfaceStructTag(cPtr, false);
  }


I've been playing with the javain typemap, and it just seems to change 
the ElementXML.getCPtr(pChild) part of the function.  Also, I didn't see 
anything in the memory management section of the Java documentation that 
addresses this issue.  What am I missing?

Thanks,
Bob