Sample PL/I Source to Invoke Commit Callback

The following source file contains an example of a PL/I module calling Java™ through the JNI to invoke the batch container commit method using the steps as described above. One may als0 think of this as simple proxy for any PL/I “main” routine launched from the z/OS® Batch Runtime and invoking simple Java methods.

Figure 1. PL/I Sample to Commit Transaction Using JNI

*Process Limits( Extname( 100 ) );
*Process Margins( 1, 100 );
*Process Display(STD) Rent;
*Process Default( ASCII ) Or('|');
*Process Options InSource Source Nest Macro Storage;
*Process Aggregate Offset;
*Process List Flag(I) MarginI('|');
*Process Opt(2) Attributes(Full) Xref(Short);
/* PL/I calling batch container commit using JNI */
PLICOMIT: Procedure Options( Fetchable
                             Assembler );

/********************************************************************/
/* */
/* This sample invokes the z/OS batch runtime to commit a */
/* transaction. */
/* */
/* The batch runtime transaction helper class is loaded and the */
/* commit method is located and invoked. */
/* */
/********************************************************************/

     /************/
     /* Includes */
     /************/
%INCLUDE ibmzjni;


     /*************/
     /* Constants */
     /*************/
Dcl NULLPTR Pointer Static Init(PtrValue(0));

Dcl TRANSACTION_HELPER_CLASS_NAME Char(60) VaryingZ Static
      Init("com/ibm/batch/spi/UserControlledTransactionHelper");

     /*******************/
     /* Local variables */
     /*******************/
Dcl myRC Fixed Bin(31);

Dcl myClass Type jclass;
Dcl myMethodID Type jmethodID;
Dcl myjstring Type jstring;

Dcl javaNumVMs Type jsize;

Dcl myNull Pointer;


Put skip list("Starting PLICOMIT ...");
     /*****************/
     /* Query the JVM */
     /*****************/
myRC = JNI_GetCreatedJavaVMs( addr(JavaVM),
                              1,
                              addr(javaNumVMs) );

If myRC = JNI_OK then
  Do;
    If javaNumVMs = 1 then
      Do;
       /*******************************/
       /* Get env pointer for our JVM */
       /*******************************/
       myRC = JGetEnv( JavaVM,
                       addr(JNIEnv),
                       JNI_VERSION_1_4 );

       If myRC ^= JNI_OK then
         Do;
           Put skip list("JGetEnv failed rc=",myRC);
           Stop;
         End;
       Else;
     End;
  Else
    Do;
      Put skip list("javaNumVMs not 1",javanumVMs);
      Stop;
    End;
  End;
Else
  Do;
    Put skip list("getCreatedJavaVMs failed",myRC);
    Stop;
  End;

     /******************************/
     /* Get the Java class to call */
     /******************************/
myClass = FindClass( JNIEnv,
                     TRANSACTION_HELPER_CLASS_NAME );
If myClass = NULLPTR then
  Do;
    Put skip list("myClass is null");
    Stop;
  End;
Else;

      /***********************************/
      /* Get method id for commit method */
      /***********************************/
myMethodID = GetStaticMethodID( JNIEnv,
                                myClass,
                                "commit",
                                "()V" );

If myMethodID = NULLPTR then
  Do;
    Put skip list("myMethodID is null");
    Stop;
  End;
Else;

Put skip list("Calling commit method ...");
myNull = CallStaticVoidMethod( JNIEnv,
                               myClass,
                               myMethodID );

Call PLIRETC(0); /* Set rc=0 */

Put skip list("PLICOMIT ended.");
End PLICOMIT;