Communications/Transactions Guide and Reference
To build an application that provides a graphical front end to a 3270-based
host application, you must add a separate 3270 Screen part for each of the
host screens your user needs to interact with. Each 3270 Screen part
uses the value of its keyString attribute (usually specified in the
part's settings view) to detect when the host screen it represents has
become active.
The 3270 Screen part's public interface provides features that help
you do the following:
- Determine which 3270 Screen part is active (based upon which host screen
is currently displayed)
- Identify the position and length of all input and output fields
- Read from and write to the screen
- Send control keystrokes such as Enter, PF, and
PA keys
The following is a list of some of the basic features of the 3270 Screen
part's public interface.
- refreshFieldDefs
- Causes the 3270 Screen part to identify the position and length of all
input and output fields on the host screen.
The 3270 Screen part only responds to the refreshFieldDefs
action if the currently displayed host screen is the one it is set up to
interact with, indicated by a matching key string. Therefore, you can
use a single event to trigger the refreshFieldDefs action
simultaneously on all of the 3270 Screen parts in your application; only
the one 3270 Screen part representing the currently displayed host screen will
respond.
- getData
- Reads the contents of all input and output fields on the host screen and
places the values in the inputFields and outputFields
attributes. The 3270 Screen part only responds to this action if the
key string matches what is on the currently displayed host screen.
- putData
- Writes to the host screen the values of the input fields contained in the
inputFields attribute.
- pressEnter
- Sends an Enter keystroke to the host application.
- fieldDefsRefreshed
- Indicates that the 3270 Screen part has read the position and length of
the input and output fields on the host screen, in response to a
refreshAll action.
Because the 3270 Screen part only performs the refreshFieldDefs
action when the screen specified by its key string is displayed, you can use
the fieldDefsRefreshed event to detect when a particular 3270
Screen has become active.
- screenChanged
- Indicates that the previously displayed host screen has been replaced by a
new one. You can use the screenChanged event to determine
when to perform some other action on the screen.
- dataRefreshed
- Indicates that the values of the fields on the host screen have been read
into the inputFields and outputFields attributes.
You can use this event to trigger further processing after completion of the
getData action.
- inputFields
- Represents all of the input fields of the host screen. The
inputFields attribute contains subparts representing each of the
individual input fields, which you can access by tearing off the
inputFields attribute.
- outputFields
- Represents all of the output fields of the host screen. The
outputFields attribute contains subparts representing each of the
individual input fields, which you can access by tearing off the
outputFields attribute.
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