Host Access Class Library for Java

Host Access Library Java Objects

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.

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