This class library presents a complete
object-oriented abstraction of a host session that includes: reading and writing the host
presentation space (screen), enumerating the fields on the screen, reading the Operator
Information Area (OIA) for status information, transferring files, and performing
asynchronous notification of significant events.
The Host Access Class Library (HACL) consists of the classes that are described briefly
in the section below. The Host Access Class Library API Documentation
(Javadoc) provides detailed information for each of the classes below.
The following is a brief overview of the Host Access Class Library classes.
ECLConnection represents the
connection information for a session with a particular host and contains information such
as the connection status, the type of connection (for example, 3270 or 5250), and the name
of the session.
ECLCommNotify is the
notification interface that must be implemented to be notified whenever a connection is
disconnected from or connected to a host. It can be used to monitor the status of a
connection, for example, to take action when a connection is disconnected unexpectedly.
ECLErr provides a method for
returning run-time error information from Host Access Class Library classes. ECLErr is
thrown by HACL objects when a problem is encountered. ECLErr contains the runtime error
information and also provides methods that applications can use for problem determination
so that the appropriate action can be taken.
ECLField contains information
about a single field on the screen, such as the field attributes, field color, position on
the screen or length. A method is also supplied to update input fields.
ECLFieldList contains a
collection of ECLField objects. When the Refresh method is called, the current host screen
is examined, and the list of fields is extracted and used to build the list of ECLField
objects. An application can use this collection to manage fields without having to build
the list itself.
ECLHostPrintSession
establishes a print connection with a host and defines the behavior and characteristics of
the print session, including the session type (3270 printer session or 5250 printer
session), PDT file name and port number.
ECLOIA provides access to operator
status information such as shift indicators, input inhibited conditions and communications
errors.
ECLOIANotify is the
notification interface that must be implemented to be notified whenever the OIA is
updated.
ECLPrintJobEvent
encapsulates a print job event. Events are generated whenever a print job is started or
completed and when print job-related errors occur.
ECLPrintJobListener
is the listener interface that must be implemented to receive print job events.
ECLPS represents the presentation
space (screen) of a single connection. It contains methods for obtaining a copy of the
screen contents in the form of data planes. Each plane represents a specific aspect of the
presentation space, such as the text, field attributes and color attributes. Methods are
provided for searching for strings in the presentation space, sending keystrokes to the
host, getting and setting the host cursor position, and many other functions. Also
provided is an ECLFieldList object that can be used to enumerate the list of fields on the
screen.
ECLPSEvent encapsulates a PS
event and includes information about which area of the presentation space has changed.
ECLPSListener is the
listener interface that must be implemented to receive ECLPSEvents.
ECLPSNotify is the
notification interface that must be implemented to be notified whenever the host
presentation space is updated. (Deprecated)
ECLRecoNotify is the
notification interface that must be implemented to be notified whenever screens are
recognized.
ECLScreenDesc contains the
data that describes a particular screen. This class can be used to perform advanced screen
recognition.
ECLScreenReco contains the
methods for adding and removing screen descriptions and provides asynchronous notification
when screens are recognized.
ECLSession contains a
collection of all the connection-specific objects. ECLSession can be used to easily create
a complete set of objects for a particular connection. ECLSession inherits from
ECLConnection, and it is the only access point for the methods in ECLConnection.
ECLXfer initiates file transfers
to or from the host over the connection.
ECLXferEvent provides
file transfer progress information.
ECLXferListener is
the listener interface which must be implemented to receive ECLXferEvents.
