Package eu.bandm.tools.message

Class MessageCatcher

java.lang.Object

eu.bandm.tools.message.SingleSender<Message>

eu.bandm.tools.message.MessageCatcher

All Implemented Interfaces:

Runnable

public abstract class MessageCatcher
extends SingleSender<Message>
implements Runnable

Executes payload code and sends the first exception caught to its given message drain.

The execution ends with the programmed end of the payload code, or when a exception is caught. Then execution can be restarted.

The payload code can be defined

1. by explicitly defining payload() in a derived class, or
2. by using the factory method tryCatch(java.lang.Runnable, eu.bandm.tools.message.MessageReceiver<eu.bandm.tools.message.Message>) with a Runnable

In either case, run() starts the controlled execution.

A caught MessageException is unwrapped and sent directly to the given MessageReceiver. All other exceptions are wrapped into a SimpleMessage of kind failure.

Errors are not caught, only Exceptions.

Field Summary

Fields

Modifier and Type	Field	Description
protected @Opt Exception	caught	local cache for the caught exception.
protected boolean	running	Whether currently running.

Fields inherited from class eu.bandm.tools.message.SingleSender

drain

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MessageCatcher()	Constructor which sets neither the message drain nor the payload code.
protected	MessageCatcher(MessageReceiver<Message> rec)	Constructor which sets only the message receiver.

Method Summary

Modifier and Type	Method	Description
@Opt Exception	getCaught()	Returns the last exception caught, if any.
boolean	isRunning()	Returns whether currently running.
protected abstract void	payload()	Override this method to define the payload code.
void	run()	Start the execution of the given payload code.
static MessageCatcher	tryCatch(Runnable payload, @Opt MessageReceiver<Message> rec)	Creates a new instance with the given payload code and message receiver.

Methods inherited from class eu.bandm.tools.message.SingleSender

getDrain, send, setDrain

Methods inherited from class java.lang.Object

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

Field Details

caught

@Opt
protected @Opt Exception caught

local cache for the caught exception.

running

protected boolean running

Whether currently running.

Constructor Details

MessageCatcher

protected MessageCatcher(MessageReceiver<Message> rec)

Constructor which sets only the message receiver. When using this constructor, subclasses must define the method payload().

Parameters:

rec - the drain for all caught messages.

See Also:

• SingleSender.setDrain(eu.bandm.tools.message.MessageReceiver<? super M>)

MessageCatcher

protected MessageCatcher()

Constructor which sets neither the message drain nor the payload code. When using this constructor, subclasses must define the method payload().

See Also:

• SingleSender.setDrain(eu.bandm.tools.message.MessageReceiver<? super M>)

Method Details

tryCatch

public static MessageCatcher tryCatch(Runnable payload,
 @Opt
 @Opt MessageReceiver<Message> rec)

Creates a new instance with the given payload code and message receiver.

Parameters:

payload - the code to execute

rec - the message drain. When null, it must be overwritten before using this instance.

Returns:

an executable object that runs payload, and sends a caught message exception to rec

See Also:

• SingleSender.setDrain(eu.bandm.tools.message.MessageReceiver<? super M>)

isRunning

public boolean isRunning()

Returns whether currently running.

Returns:

whether currently running.

getCaught

@Opt
public @Opt Exception getCaught()

Returns the last exception caught, if any.

Returns:

the last exception caught, if any.

payload

protected abstract void payload()

Override this method to define the payload code.

run

public void run()

Start the execution of the given payload code.

Specified by:

run in interface Runnable

Throws:

IllegalStateException - if called when currently running.