Screen entity

Screen entities are Plain Java Objects used as models for terminal screens.

Each screen entity is defined by four properties:

• Identifiers — unique properties that differentiate this screen from others
• Actions — terminal actions that can be performed on the screen
• Navigation — how to navigate to this screen
• Fields — relationship between a Java field and the exact position on the terminal screen

Identifiers

Specified with @ScreenIdentifiers containing an array of @Identifier. When the telnet session returns a screen, the connector matches it to an entity. Too few identifiers can match the wrong entity; too many slow recognition. Prefer a minimal unique set.

Each @Identifier has row and column, optional attribute (Color, BackColor, Editable, or default Value for text), and Value to compare. Multiple identifiers are AND.

@ScreenEntity
@ScreenIdentifiers(identifiers = { 
    @Identifier(row = 1, column = 37, value = "Main Menu"),
    @Identifier(row = 21, column = 8, value = "true", attribute = FieldAttributeType.Editable)
})
public class MainMenu {
    // ...
}

Identifiers can also be added, removed, or edited in the graphical Screen Entity Editor (use the screen preview; prefer static elements such as titles and labels).

Actions

Specified with @ScreenActions containing @Action entries:

• action (mandatory) — keyboard keys such as F1–F12, Enter, Esc
• alias — another name for the action
• displayName — demonstration only
• additionalKey — combined keystroke (for example Shift+F1 for F13)

Navigation

getEntity on the telnet session navigates to a screen and returns it as an entity. Attach @ScreenNavigation:

• accessedFrom — entity from which this screen is reachable
• terminalAction — action to navigate from accessedFrom
• exitAction — action to navigate back
• assignedFields — values to set on accessedFrom before navigating (@AssignedField)

At runtime OpenLegacy builds a navigation map. From the current screen it walks exitAction sequences to a common parent, then terminalAction sequences to the requested screen.

Fields

Specified with @ScreenField, mapping a Java field to the exact position of the terminal field on the screen.

See Screens projects and Screens SDK.

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Source: Screen Entity (Confluence)