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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
package org.jgroups;
import org.jgroups.util.MessageBatch;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Defines the callbacks that are invoked when messages, views etc are received
*
* @see JChannel#setReceiver(Receiver)
* @since 2.0
* @author Bela Ban
*/
public interface Receiver {
/**
* Called when a message is received.
* @param msg The message
*/
default void receive(Message msg) {
}
/**
* Called when a batch of messages is received
* @param batch The message batch
*/
default void receive(MessageBatch batch) {
for(Message msg: batch) {
try {
receive(msg);
}
catch(Throwable ignored) {
}
}
}
/**
* Called when a change in membership has occurred. No long running actions, sending of messages
* or anything that could block should be done in this callback. If some long running action
* needs to be performed, it should be done in a separate thread.
*
* Note that on reception of the first view (a new member just joined), the channel will not yet
* be in the connected state. This only happens when {@link JChannel#connect(String)} returns.
*/
default void viewAccepted(View new_view) {}
/**
* Called (usually by the {@link org.jgroups.protocols.pbcast.FLUSH} protocol), as an indication that the member
* should stop sending messages. Any messages sent after returning from this callback might get blocked by the FLUSH
* protocol. When the FLUSH protocol is done, and messages can be sent again, the FLUSH protocol
* will simply unblock all pending messages. If a callback for unblocking is desired, implement
* {@link org.jgroups.Receiver#unblock()}.
*/
default void block() {}
/**
* Called after the FLUSH protocol has unblocked previously blocked senders, and
* messages can be sent again.
*
* Note that during new view installation we provide guarantee that unblock invocation strictly
* follows view installation at some node A belonging to that view. However, some other message
* M may squeeze in between view and unblock callbacks.
* For more details see https://issues.redhat.com/browse/JGRP-986
*/
default void unblock() {}
/**
* Allows an application to write the state to an OutputStream. After the state has
* been written, the OutputStream doesn't need to be closed as stream closing is automatically
* done when a calling thread returns from this callback.
*
* @param output The OutputStream
* @throws Exception If the streaming fails, any exceptions should be thrown so that the state requester
* can re-throw them and let the caller know what happened
*/
default void getState(OutputStream output) throws Exception {
throw new UnsupportedOperationException("getState() needs to be overridden by applications");
}
/**
* Allows an application to read the state from an InputStream. After the state has been
* read, the InputStream doesn't need to be closed as stream closing is automatically done when a
* calling thread returns from this callback.
*
* @param input The InputStream
* @throws Exception If the streaming fails, any exceptions should be thrown so that the state requester
* can catch them and thus know what happened
*/
default void setState(InputStream input) throws Exception {
throw new UnsupportedOperationException("setState() needs to be overridden by applications");
}
}