package org.jgroups;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Interface to provide state (state provider) and set state (state requester)
* @since 4.0
* @author Bela Ban
* @author Vladimir Blagojevic
*/
public interface StateListener {
/**
* Allows an application to write a state through a provided 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
* @see OutputStream#close()
*/
default void getState(OutputStream output) throws Exception {}
/**
* Allows an application to read a state through a provided 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
* @see InputStream#close()
*/
default void setState(InputStream input) throws Exception {}
}