Method for accessing information on a host computer from a client computer through an intelligent virtual host component

• US 6,049,832 A
• Filed: 11/15/1996
• Issued: 04/11/2000
• Est. Priority Date: 11/15/1996
• Status: Expired due to Term

• Current Assignee: Micro Focus Incorporated (Open Text Corporation)
• Original Assignee: Wall Data, Inc. (Open Text Corporation)
• Inventors: Rielley, Steven Patrick, Haven, Christina Anne, Brim, David Neal, Hammack, Patrick James
• Primary Examiner(s): Asta, Frank J.
• Assistant Examiner(s): Cardone, Jason D.
• Application Number:
  US08/746,782
• Time in Patent Office: 1,243 Days
• Field of Search: 709/203, 709/237, 709/217, 709/218, 709/219, 709/225, 709/227, 709/231, 709/228, 709/250, 345/121, 345/333, 345/11, 364/188
• US Class Current: 709/237
• CPC Class Codes: G06F 16/972 Access to data in other repository systems, e.g. legacy data or dynamic Web page generation

Abstract

A method and apparatus for accessing information on a host computer (104) from a client computer (112) that are connected by a network. The information accessed by the client computer (112) is represented as a plurality of fields in a presentation space data stream (208). The fields and corresponding attribute information in the presentation space data stream (208), as received from the host computer (104), are extracted and stored in field objects contained within a Display control (202). A set of events is provided by the Display control to an application program (204), the events providing information to allow the application program (204) to manage the interaction between an operator and the host computer (104). A set of properties and methods provide the application program (204) with the ability to traverse the field objects and thereby obtain the field information sent from the host computer.

Claims

1. A method of controlling the transmission of information between a host computer and a remotely located client computer, comprising:

providing a Display control contained in an application and receiving information from the host computer;

receiving, at the Display control, a data stream that is transmitted from the host computer, a portion of the data stream indicating the host computer being in a state of ready to receive data;

upon receipt of the portion of the data stream indicating the host computer being in a state of ready to receive data, sending a first ReadyToSend event to an event handler in the application program, the first ReadyToSend event including a State parameter set to TRUE that indicates the host computer is ready to receive data;

receiving, at the Display control, input data from the client computer;

sending a second ReadyToSend event to the event handler in the application program, the second ReadyToSend event having a State parameter set to FALSE that indicates the host computer is not ready to receive data from the client computer; and

sending the input data from the Display control to the host computer.

2. The method of claim 1, wherein the host data that is transmitted from the host computer includes an SNA header containing an End Chain indicator that indicates the host computer is ready to receive data.

3. The method of claim 1, further comprising:

receiving, at the Display control, keyboard lock data that is transmitted from the host computer, the keyboard lock data indicating a condition that triggers unlocking of a keyboard of the client computer;

upon receipt of the keyboard lock data, sending a first KeyboardLock event to the application program, the first KeyboardLock event having a State parameter set to FALSE that indicates the keyboard of the client computer is unlocked;

receiving a signal at the Display control that indicates a condition that triggers locking of the keyboard; and

upon receipt of the signal, sending a second KeyboardLock event to the application program, the first KeyboardLock event having a State parameter set to TRUE that indicates the keyboard of the client computer is locked.

4. The method of claim 3, wherein the keyboard lock data that is transmitted from the host computer includes a write control character byte containing a keyboard restore bit that indicates a condition that triggers unlocking of the keyboard.

5. The method of claim 4, wherein the signal comprises a second write control character byte received from the host computer, the second write control character byte containing a keyboard restore bit indicating a condition that triggers locking of the keyboard.

6. The method of claim 3, wherein the signal indicates an Attention Identifier key has been pressed on the keyboard of the client computer.

7. The method of claim 6, further comprising:

receiving at the Display control a key selection signal indicative of at least one key selection from the keyboard of the client computer; and

upon receipt of the key selection signal indicative of at least one key selection, sending a HostKeyPress event to the application program, the HostKeyPress event including a Key parameter containing at least one character representative of the key selection.

8. The method of claim 7, further comprising:

translating the key selection into a string of at least two characters, the string including a mnemonic representation of the key selection.

9. The method of claim 8, further comprising upon receipt of the key selection signal indicative of at least one key selection, sending an EncodeData event to the application program , wherein the sending of the EncodeData event is performed prior to the sending of the input data.

10. The method of claim 6, further comprising:

receiving at the Display control a field movement signal indicative of the operator moving from a first field to a second field; and

upon receipt of the field movement signal, sending an InNewField event to the application program, the InNewField event including a FieldIndex parameter representative of an index value corresponding to the second field.

11. The method of claim 6, further comprising:

receiving at the Display control an insert signal indicative of a selection of an Insert key from the keyboard of the client computer, and

upon receipt of the insert signal, sending an InsertModeEnabled event to the application program, the InsertModeEnabled event including an Enabled parameter that is set to TRUE when the keyboard is in insert mode.

12. A method of providing information from a host computer to an application program running on a remotely located client computer, the method comprising:

providing a Display control and an associated collection object contained in the application program;

receiving, at the Display control, a presentation space data stream from the host computer, the presentation space data stream including a plurality of information fields;

scanning the presentation space data stream to locate each of the information fields;

creating a plurality of field objects, each of which has a corresponding information field and an associated unique index value;

storing in each field object a plurality of properties pertaining to its corresponding information field in the presentation space data stream, the properties including;

text obtained from the corresponding information field; and

the length of the corresponding information field;

storing, in the collection object, a reference to at least one of the field objects;

receiving, at the Display control, a request from the application program, via methods provided by the Display control, for a reference to the collection object;

receiving, at the Display control, a request from the application program, via methods provided by the Display control, for a reference to one of the plurality of field objects, the request including an index value indicative of the requested one of the plurality of field objects;

receiving, at the Display control, a request from the application program, via methods provided by the Display control, for the text stored in the requested one of the field objects;

returning, from the Display control to the application program, a string containing the text stored in the requested field object;

receiving, at the Display control, a request from the application program, via methods provided by the Display control, for the length of the information field corresponding to the requested field object; and

returning from the Display control to the application program, a valve indicative of the length of the information field corresponding to the requested field object.

13. The method of claim 12, wherein the properties stored in each field object further include a protected property that indicates whether the host computer permits changes to the field from the client computer.

14. A method for accessing information on a host computer from remotely located client computers, the method comprising:

providing a Display control within a container running on one of the plurality of client computers for communicating with the host computer;

transmitting a data stream from the host computer, the data stream comprising field information and a ready indicator representing the host computer is ready to receive data, the field information comprising a plurality of fields each having an associated field descriptor;

receiving the data stream at the Display control;

parsing the data stream by the Display control, and upon parsing any of the field information, converting the field information into a hierarchical object structure;

displaying the field information in a display control window on the client computer;

modifying the field information displayed in the display control window by invoking a method of one of a plurality of objects in the hierarchical object structure for the Display control;

upon receiving a predetermined key entry from the client application, the Display control transmitting the modified field information to the host computer.

15. The method of claim 14, wherein converting the field information into a hierarchical object structure comprises:

creating a plurality of field objects for each field; and

storing in each field object a plurality of properties that correspond to the associated field descriptor.

16. The method of claim 15, wherein converting the field information into a hierarchical object structure further comprises:

creating a collection object with a reference to at least one of the field objects.

17. The method of claim 16, wherein the reference comprises an index representing a relative order for the field object determined during parsing of the data stream.

18. The method of claim 14, wherein the container comprises an application running on the client computer.