Communication of objects including Java bytecodes between 3270 logical units including Java virtual machines

• US 6,327,624 B1
• Filed: 05/06/1998
• Issued: 12/04/2001
• Est. Priority Date: 05/06/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Peters, Marcia Lambert, Mathewson, James Merwin II
• Primary Examiner(s): Harrell, Robert B.
• Assistant Examiner(s): YUAN, ALMARI ROMERO
• Application Number:
  US09/073,424
• Time in Patent Office: 1,308 Days
• Field of Search: 709/231, 709/227, 709/236, 709/237, 709/305, 709/221, 709/224, 709/213, 709/226, 709/311, 709/219
• US Class Current: 709/231
• CPC Class Codes: G06F 8/76 Adapting program code to run in a different environment; Porting
• CPC Class Codes: G06F 9/54 Interprogram communication

Abstract

Java and other objects are integrated with legacy 3270 applications by sending 3270 datastream communications between a primary logical unit (LU) and a secondary LU over a network using 3270 datastream architecture and sending 3270 datastream structured fields including embedded objects such as Java bytecodes between the primary LU and the secondary LU over the network using 3270 datastream architecture. The sending of 3270 datastream communications and the sending of 3270 datastream structured fields are repeated in an arbitrary sequence, to thereby asynchronously send 3270 datastreams and objects such as Java bytecodes between the primary LU and the secondary LU over the network using 3270 datastream architecture. Thus, objects such as Java bytecodes are sent using the LU2 protocol in a manner that need not interfere with legacy communications between a 3270 application and an end user.

Claims

1. A method for passing Java bytecodes from a first Java Virtual Machine (JVM) in a Primary Logical Unit (PLU) to a second JVM in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending Java bytecodes from the first JVM to the corresponding PLU;

waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

if the session is between brackets, sending a Begin Brackets request header from the PLU to the SLU;

sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein; and

sending the embedded Java bytecodes from the SLU to the second JVM.

2. A method according to claim 1:

wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises the step of setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is expected; and

wherein the step of sending the embedded Java bytecodes from the SLU to the second JVM is followed by the steps of;

sending reply Java bytecodes from the second JVM to the SLU;

sending an In Brackets, Change Direction request header from the SLU to the PLU;

sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

sending the embedded reply Java bytecodes from the PLU to the corresponding first JVM.

3. A method according to claim 2 wherein the step of sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply Java bytecodes embedded therein, is followed by the step of:

sending an End Brackets, Change Direction request header from the PLU to the SLU.

4. A method according to claim 2 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

5. A method according to claim 1:

wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises the step of setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is not expected.

6. A method according to claim 1 wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises the step of:

sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the Java bytecodes embedded therein.

7. A method for passing Java bytecodes from a second Java Virtual Machine (JVM) in a Secondary Logical Unit (SLU) to a first JVM in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending Java bytecodes from the second JVM to the corresponding SLU;

waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the Java bytecodes embedded therein;

if the chain does not contain all of the Java bytecodes embedded therein, sending a Change Direction request header from the PLU to the SLU;

if the chain does not contain all of the Java bytecodes embedded therein, repeating the step of sending a Change Direction request header and the step of sending a chain from the SLU to the PLU, until all the embedded Java bytecodes have been sent from the SLU to the PLU; and

sending the embedded Java bytecodes from the PLU to the first JVM after all the embedded Java bytecodes have been sent from the SLU to the PLU.

8. A method according to claim 7 wherein the step of sending the embedded Java bytecodes from the PLU to the first JVM after all the embedded Java bytecodes have been sent from the SLU to the PLU, is followed by the following steps if a synchronous reply to the embedded Java bytecodes is expected:

sending reply Java bytecodes from the first JVM to the PLU;

sending an End Brackets chain from the PLU to the SLU;

sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

sending the embedded reply Java bytecodes from the SLU to the corresponding second JVM.

9. A method according to claim 8 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

10. A method for passing streaming audio from an audio server in a Primary Logical Unit (PLU) to an audio client in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending streaming audio from the audio server to the PLU;

sending a Begin Brackets/End Brackets request header from the PLU to the SLU;

sending a single request unit from the PLU to the SLU, the single request unit containing a 3270 datastream structured field with the streaming audio embedded therein;

sending the embedded streaming audio from the SLU to the audio client; and

playing the streaming audio in the audio client.

11. A method according to claim 10 wherein the following steps are performed between the steps of sending streaming audio from the audio server to the PLU, and sending a Begin Brackets/End Brackets request header from the PLU to the SLU:

sending a request header from the SLU to the PLU; and

sending a request unit from the SLU to the PLU, the request unit containing a 3270 datastream therein.

12. A method for communicating between a Primary Logical Unit (PLU) and a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending 3270 datastream communications between the PLU and the SLU over the network using 3270 datastream architecture;

sending 3270 datastream structured fields including embedded Java bytecodes between the PLU and the SLU over the network using 3270 datastream architecture; and

repeatedly performing the step of sending 3270 datastream communications and the step of sending 3270 datastream structured fields, in an arbitrary sequence, to thereby send 3270 datastreams and Java bytecodes between the PLU and the SLU over the network using 3270 datastream architecture.

13. A method according to claim 12 wherein the Java bytecodes are a Java applet.

14. A system for passing Java bytecodes from a first Java Virtual Machine (JVM) in a Primary Logical Unit (PLU) to a second JVM in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the system comprising:

means for sending Java bytecodes from the first JVM to the corresponding PLU;

means for waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

means for sending a Begin Brackets request header from the PLU to the SLU if the session is between brackets;

means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein; and

means for sending the embedded Java bytecodes from the SLU to the second JVM.

15. A system according to claim 14:

wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises means for setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is expected; and

wherein the system further comprises;

means for sending reply Java bytecodes from the second JVM to the SLU;

means for sending an In Brackets, Change Direction request header from the SLU to the PLU;

means for sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

means for sending the embedded reply Java bytecodes from the PLU to the corresponding first JVM.

16. A system according to claim 15 further comprising:

means for sending an End Brackets, Change Direction request header from the PLU to the SLU.

17. A system according to claim 15 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

18. A system according to claim 14:

wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises means for setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is not expected.

19. A system according to claim 14 wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises:

means for sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the Java bytecodes embedded therein.

20. A system for passing Java bytecodes from a second Java Virtual Machine (JVM) in a Secondary Logical Unit (SLU) to a first JVM in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the system comprising:

means for sending Java bytecodes from the second JVM to the corresponding SLU;

means for waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

means for sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

means for sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the Java bytecodes embedded therein;

means for sending a Change Direction request header from the PLU to the SLU if the chain does not contain all of the Java bytecodes embedded therein;

means for repeatedly sending a Change Direction request header and repeatedly sending a chain from the SLU to the PLU, until all the embedded Java bytecodes have been sent from the SLU to the PLU if the chain does not contain all of the Java bytecodes embedded therein; and

means for sending the embedded Java bytecodes from the PLU to the first JVM after all the embedded Java bytecodes have been sent from the SLU to the PLU.

21. A system according to claim 20 further comprising:

means for sending reply Java bytecodes from the first JVM to the PLU if a synchronous reply to the embedded Java bytecodes is expected;

means for sending an End Brackets chain from the PLU to the SLU;

means for sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

means for sending the embedded reply Java bytecodes from the SLU to the corresponding second JVM.

22. A system according to claim 21 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

23. A system for passing streaming audio from an audio server in a Primary Logical Unit (PLU) to an audio client in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the system comprising:

means for sending streaming audio from the audio server to the PLU;

means for sending a Begin Brackets/End Brackets request header from the PLU to the SLU;

means for sending a single request unit from the PLU to the SLU, the single request unit containing a 3270 datastream structured field with the streaming audio embedded therein;

means for sending the embedded streaming audio from the SLU to the audio client; and

means for playing the streaming audio in the audio client.

24. A system according to claim 23 further comprising:

means for sending a request header from the SLU to the PLU; and

means for sending a request unit from the SLU to the PLU, the request unit containing a 3270 datastream therein.

25. A computer program product for passing Java bytecodes from a first Java Virtual Machine (JVM) in a Primary Logical Unit (PLU) to a second JVM in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the computer program product comprising a computer-readable storage medium having computer-readable program code means embodied in the medium, the computer-readable program code means comprising:

computer-readable program code means for sending Java bytecodes from the first JVM to the corresponding PLU;

computer-readable program code means for waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

computer-readable program code means for sending a Begin Brackets request header from the PLU to the SLU if the session is between brackets;

computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein; and

computer-readable program code means for sending the embedded Java bytecodes from the SLU to the second JVM.

26. A computer program product according to claim 25:

wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises the computer-readable program code means for setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is expected; and

wherein the computer program product further comprises;

computer-readable program code means for sending reply Java bytecodes from the second JVM to the SLU;

computer-readable program code means for sending an In Brackets, Change Direction request header from the SLU to the PLU;

computer-readable program code means for sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

computer-readable program code means for sending the embedded reply Java bytecodes from the PLU to the corresponding first JVM.

27. A computer program product according to claim 26 further comprising:

computer-readable program code means for sending an End Brackets, Change Direction request header from the PLU to the SLU.

28. A computer program product according to claim 26 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

29. A computer program product according to claim 25:

wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises computer-readable program code means for setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, if a synchronous reply to the Java bytecodes is not expected.

30. A computer program product according to claim 25 wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the Java bytecodes embedded therein, comprises:

computer-readable program code means for sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the Java bytecodes embedded therein.

31. A computer program product for passing Java bytecodes from a second Java Virtual Machine (JVM) in a Secondary Logical Unit (SLU) to a first JVM in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the computer program product comprising a computer-readable storage medium having computer-readable program code means embodied in the medium, the computer-readable program means comprising:

computer-readable program code means for sending Java bytecodes from the second JVM to the corresponding SLU;

computer-readable program code means for waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

computer-readable program code means for sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

computer-readable program code means for sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the Java bytecodes embedded therein,

computer-readable program code means for sending a Change Direction request header from the PLU to the SLU if the chain does not contain all of the Java bytecodes embedded therein;

computer-readable program code means for repeatedly sending a Change Direction request header and repeatedly sending a chain from the SLU to the PLU, until all the embedded Java bytecodes have been sent from the SLU to the PLU if the request unit does not contain all of the Java bytecodes embedded therein; and

computer-readable program code means for sending the embedded Java bytecodes from the PLU to the first JVM after all the embedded Java bytecodes have been sent from the SLU to the PLU.

32. A computer program product according to claim 31 further comprising:

computer-readable program code means for sending reply Java bytecodes from the first JVM to the PLU if a synchronous reply to the embedded Java bytecodes is expected;

computer-readable program code means for sending an End Brackets chain from the PLU to the SLU;

computer-readable program code means for sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply Java bytecodes embedded therein; and

computer-readable program code means for sending the embedded reply Java bytecodes from the SLU to the corresponding second JVM.

33. A computer program product according to claim 32 wherein the Java bytecodes are a request for a Java class file and wherein the reply Java bytecodes are a Java applet corresponding to the Java class file.

34. A computer program product for passing streaming audio from an audio server in a Primary Logical Unit (PLU) to an audio client in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the computer program product comprising a computer-readable storage medium having computer-readable program code means embodied in the medium, the computer-readable program code means comprising:

computer-readable program code means for sending streaming audio from the audio server to the PLU;

computer-readable program code means for sending a Begin Brackets/End Brackets request header from the PLU to the SLU;

computer-readable program code means for sending a single request unit from the PLU to the SLU, the single request unit containing a 3270 datastream structured field with the streaming audio embedded therein;

computer-readable program code means for sending the embedded streaming audio from the SLU to the audio client; and

computer-readable program code means for playing the streaming audio in the audio client.

35. A computer program product according to claim 34 further comprising:

computer-readable program code means for sending a request header from the SLU to the PLU; and

computer-readable program code means for sending a request unit from the SLU to the PLU, the request unit containing a 3270 datastream therein.

36. A method for passing objects from a first object handler in a Primary Logical Unit (PLU) to a second object handler in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending an object from the first object handler to the corresponding PLU;

waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

if the session is between brackets, sending a Begin Brackets request header from the PLU to the SLU;

sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein; and

sending the embedded object from the SLU to the second object handler.

37. A method according to claim 36:

wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises the step of setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is expected; and

wherein the step of sending the embedded object from the SLU to the second object handler is followed by the steps of;

sending a reply object from the second object handler to the SLU;

sending an In Brackets, Change Direction request header from the SLU to the PLU;

sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply object embedded therein; and

sending the embedded reply object from the PLU to the corresponding first object handler.

38. A method according to claim 37 wherein the step of sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply object embedded therein, is followed by the step of:

sending an End Brackets, Change Direction request header from the PLU to the SLU.

39. A method according to claim 36:

wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises the step of setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is not expected.

40. A method according to claim 36 wherein the step of sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises the step of:

sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the object embedded therein.

41. A method for passing objects from a second object handler in a Secondary Logical Unit (SLU) to a first object handler in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the method comprising the steps of:

sending an object from the second object handler to the corresponding SLU;

waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the object embedded therein;

if the chain does not contain all of the object embedded therein, sending a Change Direction request header from the PLU to the SLU;

if the chain does not contain all of the object embedded therein, repeating the step of sending a Change Direction request header and the step of sending a chain from the SLU to the PLU, until all the embedded object has been sent from the SLU to the PLU; and

sending the embedded object from the PLU to the first object handler after all the embedded object has been sent from the SLU to the PLU.

42. A method according to claim 41 wherein the step of sending the embedded object from the PLU to the first object handler after all the embedded object has been sent from the SLU to the PLU, is followed by the following steps if a synchronous reply to the embedded object is expected:

sending a reply object from the first object handler to the PLU;

sending an End Brackets chain from the PLU to the SLU;

sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply object embedded therein; and

sending the embedded reply object from the SLU to the corresponding second object handler.

43. A system for passing objects from a first object handler in a Primary Logical Unit (PLU) to a second object handler in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the system comprising:

means for sending an object from the first object handler to the corresponding PLU;

means for waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

means for sending a Begin Brackets request header from the PLU to the SLU if the session is between brackets;

means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein; and

means for sending the embedded object from the SLU to the second object handler.

44. A system according to claim 43;

wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises means for setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is expected; and

wherein the system further comprises;

means for sending a reply object from the second object handler to the SLU;

means for sending an In Brackets, Change Direction request header from the SLU to the PLU;

means for sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply object embedded therein; and

means for sending the embedded reply object from the PLU to the corresponding first JVM.

45. A system according to claim 44 further comprising:

means for sending an End Brackets, Change Direction request header from the PLU to the SLU.

46. A system according to claim 43:

wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises means for setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is not expected.

47. A system according to claim 43 wherein the means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises:

means for sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the object embedded therein.

48. A system for passing objects from a second object handler in a Secondary Logical Unit (SLU) to a first object handler in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the system comprising:

means for sending an object from the second object handler to the corresponding SLU;

means for waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

means for sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

means for sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the object embedded therein;

means for sending a Change Direction request header from the PLU to the SLU if the chain does not contain all of the object embedded therein;

means for repeatedly sending a Change Direction request header and repeatedly sending a chain from the SLU to the PLU, until all the embedded Java bytecodes have been sent from the SLU to the PLU if the chain does not contain all of the Java bytecodes embedded therein; and

means for sending the embedded Java bytecodes from the PLU to the first object handler after all the embedded Java bytecodes have been sent from the SLU to the PLU.

49. A system according to claim 48 further comprising:

means for sending a reply object from the first object handler to the PLU if a synchronous reply to the embedded object is expected;

means for sending an End Brackets chain from the PLU to the SLU;

means for sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply object embedded therein; and

means for sending the embedded reply object from the SLU to the corresponding second object handler.

50. A computer program product for passing objects from a first object handler in a Primary Logical Unit (PLU) to a second object handler in a Secondary Logical Unit (SLU) that communicate with each other over a network using 3270 datastream architecture, the computer program product comprising a computer-readable storage medium having computer-readable program code means embodied in the medium, the computer-readable program code means comprising:

computer-readable program code means for sending an object from the first object handler to the corresponding PLU;

computer-readable program code means for waiting until a 3270 communications session between the PLU and the SLU is between brackets, or is in brackets and the PLU has permission to send;

computer-readable program code means for sending a Begin Brackets request header from the PLU to the SLU if the session is between brackets;

computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein; and

computer-readable program code means for sending the embedded object from the SLU to the second object handler.

51. A computer program product according to claim 50:

wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises the computer-readable program code means for setting an In Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is expected; and

wherein the computer program product further comprises;

computer-readable program code means for sending a reply object from the second object handler to the SLU;

computer-readable program code means for sending an In Brackets, Change Direction request header from the SLU to the PLU;

computer-readable program code means for sending at least one request unit from the SLU to the PLU, the at least one request unit containing a 3270 datastream structured field with the reply object embedded therein; and

computer-readable program code means for sending the embedded reply object from the PLU to the corresponding first object handler.

52. A computer program product according to claim 51 further comprising:

computer-readable program code means for sending an End Brackets, Change Direction request header from the PLU to the SLU.

53. A computer program product according to claim 50:

wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises computer-readable program code means for setting an End Brackets indicator in a last of the at least one request unit containing a 3270 datastream structured field with the object embedded therein, if a synchronous reply to the object is not expected.

54. A computer program product according to claim 50 wherein the computer-readable program code means for sending at least one request unit from the PLU to the SLU, the at least one request unit containing a 3270 datastream structured field with the object embedded therein, comprises:

computer-readable program code means for sequentially sending a plurality of chained request units from the PLU to the SLU, the plurality of chained request units containing the 3270 datastream structured field with the object embedded therein.

55. A computer program product for passing objects from a second object handler in a Secondary Logical Unit (SLU) to a first object handler in a Primary Logical Unit (PLU) that communicate with each other over a network using 3270 datastream architecture, the computer program product comprising a computer-readable storage medium having computer-readable program code means embodied in the medium, the computer-readable program means comprising:

computer-readable program code means for sending an object from the second object handler to the corresponding SLU;

computer-readable program code means for waiting until a 3270 communications session between the PLU and the SLU is in brackets and the SLU has permission to send;

computer-readable program code means for sending a Begin Brackets, Change Direction request header from the SLU to the PLU;

computer-readable program code means for sending a chain from the SLU to the PLU, the chain containing a 3270 datastream structured field with at least some of the object embedded therein;

computer-readable program code means for sending a Change Direction request header from the PLU to the SLU if the chain does not contain all of the object embedded therein;

computer-readable program code means for repeatedly sending a Change Direction request header and repeatedly sending a chain from the SLU to the PLU, until all the embedded object has been sent from the SLU to the PLU if the request unit does not contain all of the object embedded therein; and

computer-readable program code means for sending the embedded object from the PLU to the first object handler after all the embedded object has been sent from the SLU to the PLU.

56. A computer program product according to claim 55 further comprising:

computer-readable program code means for sending a reply object from the first object handler to the PLU if a synchronous reply to the embedded object is expected;

computer-readable program code means for sending an End Brackets chain from the PLU to the SLU;

computer-readable program code means for sending at least one chain from the PLU to the SLU, the at least one chain containing a 3270 datastream structured field with the reply object embedded therein; and

computer-readable program code means for sending the embedded reply object from the SLU to the corresponding second JVM.