/*
* Copyright 2014 University of Southern California
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package edu.usc.pgroup.floe.examples.pellets;
import edu.usc.pgroup.floe.app.AppContext;
import edu.usc.pgroup.floe.app.Emitter;
import edu.usc.pgroup.floe.app.Tuple;
import edu.usc.pgroup.floe.app.pellets.PelletContext;
import edu.usc.pgroup.floe.app.pellets.Signallable;
import edu.usc.pgroup.floe.app.pellets.StatelessPellet;
import edu.usc.pgroup.floe.signals.PelletSignal;
import edu.usc.pgroup.floe.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
/**
* @author kumbhare
*/
public class HelloGreetingPellet
extends StatelessPellet implements Signallable {
/**
* the global logger instance.
*/
private static final Logger LOGGER =
LoggerFactory.getLogger(HelloGreetingPellet.class);
/**
* The setup function is called once to let the pellet initialize.
* @param appContext Application's context. Some data related to
* application's deployment.
* @param pelletContext Pellet instance context. Related to this
* particular pellet instance.
*/
@Override
public void onStart(final AppContext appContext,
final PelletContext pelletContext) {
}
/**
* The execute method which is called for each tuple.
*
* @param t input tuple received from the preceding pellet.
* @param emitter An output emitter which may be used by the user to emmit
*/
@Override
public final void execute(final Tuple t, final Emitter emitter) {
if (t == null) {
LOGGER.info("Dummy execute Hello.");
} else {
LOGGER.info("Hello " + t.get("word"));
}
}
/**
* The teardown function, called when the topology is killed.
* Or when the Pellet instance is scaled down.
*/
@Override
public void teardown() {
}
/**
* @return The names of the streams to be used later during emitting
* messages.
*/
@Override
public final List<String> getOutputStreamNames() {
return null;
}
/**
* Called when a signal is received for the component.
*
* @param signal the signal received for this pellet.
*/
@Override
public final void onSignal(final PelletSignal signal) {
LOGGER.info("RECEIVED SIGNAL: {}",
Utils.deserialize(signal.getSignalData()));
}
}