Package eu.bandm.tools.message

Class MessageMapper<M extends Message,N extends Message>

java.lang.Object

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

eu.bandm.tools.message.MessageMapper<M,N>

Type Parameters:

M - the type of the ingoing messages

N - the type of the outgoing messages

All Implemented Interfaces:

MessageReceiver<M>

public class MessageMapper<M extends Message,N extends Message>
extends SingleSender<N>
implements MessageReceiver<M>

A message receiver which receives a message of one type, and propagates the result of applying a function to this message, which may be of different type. If receiver is set to null and a message is received, the code intentionally crashes.

(Since the types of in and out messages can be different, this general class cannot be a suclass of MessagePasser.)

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	allowPartialFunctions	Whether a null value coming from the mapping function means not to send anything.
protected Function<? super M,? extends N>	fun	The function to apply to all incoming messages.

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

drain

Constructor Summary

Constructors

Constructor	Description
MessageMapper(Function<? super M,? extends N> fun)	Will apply the specified total function to each received message and propagate it to a receiver.
MessageMapper(Function<? super M,? extends N> fun, boolean p)	Will apply the specified function to each received message and propagate it to a receiver.
MessageMapper(Function<? super M,? extends N> fun, boolean p, @Opt MessageReceiver<N> drain)	Will apply the specified function to each received message and propagate it to a receiver.

Method Summary

Modifier and Type	Method	Description
static <M extends Message, N extends Message> Function<MessageReceiver<N>,MessageReceiver<M>>	lift(Function<M,? extends N> f)	Delivers a function which applied to a message receiver for type "N" will deliver a message receiver for type "M".
void	receive(M message)	Apply the function and send its result to the current drain.
protected MessageMapper<M,N>	setAllowPartialFunctions(boolean b)	Change whether the function may be partial and null results are ignored and not treated as error.
protected MessageMapper<M,N>	setFunction(Function<? super M,? extends N> fun)	Change the function to apply to the incoming messages.

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

getDrain, getReceiver, send, setDrain, setReceiver

Methods inherited from class java.lang.Object

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

Methods inherited from interface eu.bandm.tools.message.MessageReceiver

ifSubcriticalThen, ifSubcriticalThen, ifSubcriticalThenElse

Field Details

fun

protected Function<? super M extends Message,? extends N extends Message> fun

The function to apply to all incoming messages.

allowPartialFunctions

protected boolean allowPartialFunctions

Whether a null value coming from the mapping function means not to send anything. Otherwise, it is an error.

Constructor Details

MessageMapper

public MessageMapper(Function<? super M,? extends N> fun,
 boolean p,
 @Opt
 @Opt MessageReceiver<N> drain)

Will apply the specified function to each received message and propagate it to a receiver.

Parameters:

fun - the function to apply to all received messages.

p - whether partial functions returning null are allowed.

drain - the receiver to which the function results are propagated.

MessageMapper

public MessageMapper(Function<? super M,? extends N> fun,
 boolean p)

Will apply the specified function to each received message and propagate it to a receiver. The receiver must be set before the first message is received; otherwise the code will intentionally crash.

Parameters:

fun - the function to apply to all received messages.

p - whether partial functions returning null are allowed.

See Also:

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

MessageMapper

public MessageMapper(Function<? super M,? extends N> fun)

Will apply the specified total function to each received message and propagate it to a receiver. Partial functions returning null are not allowed. The receiver must be set before the first message is received; otherwise the code will intentionally crash.

Parameters:

fun - the function to apply to all received messages.

Method Details

setFunction

protected MessageMapper<M,N> setFunction(Function<? super M,? extends N> fun)

Change the function to apply to the incoming messages.

Parameters:

fun - the new value of the Function.

Returns:

this instance, for method chaining.

setAllowPartialFunctions

protected MessageMapper<M,N> setAllowPartialFunctions(boolean b)

Change whether the function may be partial and null results are ignored and not treated as error.

Parameters:

b - the new value of that flag.

Returns:

this instance, for method chaining.

receive

public void receive(M message)

Apply the function and send its result to the current drain. If the value of SingleSender.drain is null, then the code crashes intentionally.

Specified by:

receive in interface MessageReceiver<M extends Message>

Parameters:

message - the message to process and propagate.

lift

public static <M extends Message,
N extends Message>
Function<MessageReceiver<N>,MessageReceiver<M>> lift(Function<M,? extends N> f)

Delivers a function which applied to a message receiver for type "N" will deliver a message receiver for type "M". A function must be given which maps the messages the other way round.

Type Parameters:

M - the message type for the resulting receiver

N - the message type for the receiver as the function argument.

Parameters:

f - function which maps messages compatible with the resulting receiver to those compatible with the argument receiver.

Returns:

the function to produce modified message receivers.