Package org.apache.juneau.terminal.bus

Class TerminalInput

java.lang.Object

org.apache.juneau.terminal.bus.TerminalInput

All Implemented Interfaces:

UpstreamHandler

public final class TerminalInput
extends Object
implements UpstreamHandler

The term.input upstream handler: hands keystrokes from a browser terminal card to a TerminalSink.

Wiring. The handler answers through the bus, but the bus is built from the policy that holds the handler, so the bus is bound afterwards, once:

TerminalInput input = TerminalInput.create(access); ServerBus bus = ServerBus.create(BusPolicy.create() .upstream(TerminalInput.TOPIC, input) .downstream(TerminalInput.STATUS_TOPIC, false) .build()); input.bind(bus);

A frame's payload is {"id": <terminal id>, "data": <string>}; an empty data is a probe. Every probe, and every refused data frame, is answered on STATUS_TOPIC to the sending session only, with {"id", "state"}, where the state is live, denied, closed, busy or bad. An accepted data frame gets no answer. The id is echoed only when it is a valid terminal id; otherwise the answer has no id key.

Typing needs both TerminalAccess.canWatch(TerminalCaller, String) and a present TerminalAccess.inputSink(TerminalCaller, String). The bus's maxUpstreamPerSecond policy (20 by default) bounds the frame rate per session, which is why the client batches keystrokes.

Each accepted non-empty write is audited at INFO on the juneau.terminal.input logger as principal=<name or -> terminal=<id> bytes=<n> keys=<list>, where the list names the control keys present (for example keys=^C,ESC,CR), comma-separated, in order of first appearance, at most 8. The typed content is never logged. Refusals log at FINE with the state only.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	STATUS_TOPIC	The downstream topic carrying the per-session answers.
static final String	TOPIC	The upstream topic carrying keystrokes.

Method Summary

Modifier and Type	Method	Description
TerminalInput	bind(ServerBus bus)	Binds the bus the answers are published on.
static TerminalInput	create(TerminalAccess access)	Creates a handler.
void	handle(BusSession session, String topic, JsonMap payload)	Handles one term.input frame.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

TOPIC

public static final String TOPIC

The upstream topic carrying keystrokes.

See Also:

• Constant Field Values

STATUS_TOPIC

public static final String STATUS_TOPIC

The downstream topic carrying the per-session answers. Never retained.

See Also:

• Constant Field Values

Method Details

create

public static TerminalInput create(TerminalAccess access)

Creates a handler.

Parameters:

access - Who may watch and who may type. Must not be null.

Returns:

A new, unbound handler.

Throws:

IllegalArgumentException - If access is null.

bind

public TerminalInput bind(ServerBus bus)

Binds the bus the answers are published on. May be called once.

Parameters:

bus - The bus whose policy holds this handler. Must not be null.

Returns:

This object.

Throws:

IllegalArgumentException - If bus is null.

IllegalStateException - If a bus is already bound.

handle

public void handle(BusSession session,
 String topic,
 JsonMap payload)
            throws Exception

Handles one term.input frame.

Specified by:

handle in interface UpstreamHandler

Parameters:

session - The sending session. Answers go to it only.

topic - The topic, TOPIC.

payload - The frame payload, {"id", "data"}.

Throws:

IllegalStateException - If no bus is bound.

Exception - Whatever the sink's write throws; the bus answers bus:upstream-failed.