/*
* Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. licenses this file to you 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 org.wso2.siddhi.core.trigger;
import org.wso2.siddhi.core.config.ExecutionPlanContext;
import org.wso2.siddhi.core.event.Event;
import org.wso2.siddhi.core.stream.StreamJunction;
import org.wso2.siddhi.query.api.definition.TriggerDefinition;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
/**
* Implementation of {@link EventTrigger} which will trigger events based on a pre-defined period.
*/
public class PeriodicEventTrigger implements EventTrigger {
private TriggerDefinition triggerDefinition;
private ExecutionPlanContext executionPlanContext;
private StreamJunction streamJunction;
private ScheduledFuture scheduledFuture;
@Override
public void init(TriggerDefinition triggerDefinition, ExecutionPlanContext executionPlanContext, StreamJunction
streamJunction) {
this.triggerDefinition = triggerDefinition;
this.executionPlanContext = executionPlanContext;
this.streamJunction = streamJunction;
}
@Override
public TriggerDefinition getTriggerDefinition() {
return triggerDefinition;
}
@Override
public String getId() {
return triggerDefinition.getId();
}
/**
* This will be called only once and this can be used to acquire
* required resources for the processing element.
* This will be called after initializing the system and before
* starting to process the events.
*/
@Override
public void start() {
scheduledFuture = executionPlanContext.getScheduledExecutorService().scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
long currentTime = executionPlanContext.getTimestampGenerator().currentTime();
streamJunction.sendEvent(new Event(currentTime, new Object[]{currentTime}));
}
}, triggerDefinition.getAtEvery(), triggerDefinition.getAtEvery(), TimeUnit.MILLISECONDS);
}
/**
* This will be called only once and this can be used to release
* the acquired resources for processing.
* This will be called before shutting down the system.
*/
@Override
public void stop() {
if (scheduledFuture != null) {
scheduledFuture.cancel(true);
}
}
}