eu.stratosphere.runtime.io.gates.Gate Maven / Gradle / Ivy
/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.runtime.io.gates;
import eu.stratosphere.core.io.IOReadableWritable;
import eu.stratosphere.nephele.event.task.AbstractEvent;
import eu.stratosphere.nephele.event.task.AbstractTaskEvent;
import eu.stratosphere.nephele.event.task.EventListener;
import eu.stratosphere.nephele.event.task.EventNotificationManager;
import eu.stratosphere.runtime.io.channels.ChannelType;
import eu.stratosphere.nephele.jobgraph.JobID;
import java.io.IOException;
/**
* In Nephele a gate represents the connection between a user program and the processing framework. A gate
* must be connected to exactly one record reader/writer and to at least one channel. The Gate class itself
* is abstract. A gate automatically created for every record reader/writer in the user program. A gate can only be used
* to transport one specific type of records.
*
* This class in general is not thread-safe.
*
* @param
* the record type to be transported from this gate
*
* TODO refactor with changes to input side
*/
public abstract class Gate {
/**
* The ID of the job this gate belongs to.
*/
private final JobID jobID;
/**
* The ID of this gate.
*/
private final GateID gateID;
/**
* The index of the gate in the list of available input/output gates.
*/
private final int index;
/**
* The event notification manager used to dispatch events.
*/
private final EventNotificationManager eventNotificationManager = new EventNotificationManager();
/**
* The type of input/output channels connected to this gate.
*/
private ChannelType channelType = ChannelType.NETWORK;
/**
* Constructs a new abstract gate
*
* @param jobID
* the ID of the job this gate belongs to
* @param gateID
* the ID of this gate
* @param index
* the index of the gate in the list of available input/output gates.
*/
protected Gate(final JobID jobID, final GateID gateID, final int index) {
this.jobID = jobID;
this.gateID = gateID;
this.index = index;
}
public final int getIndex() {
return this.index;
}
/**
* Returns the event notification manager used to dispatch events.
*
* @return the event notification manager used to dispatch events
*/
protected final EventNotificationManager getEventNotificationManager() {
return this.eventNotificationManager;
}
public String toString() {
return "Gate " + this.index;
}
public final void subscribeToEvent(EventListener eventListener, Class eventType) {
this.eventNotificationManager.subscribeToEvent(eventListener, eventType);
}
public final void unsubscribeFromEvent(final EventListener eventListener,
final Class eventType) {
this.eventNotificationManager.unsubscribeFromEvent(eventListener, eventType);
}
public final void deliverEvent(final AbstractTaskEvent event) {
this.eventNotificationManager.deliverEvent((AbstractTaskEvent) event);
}
public final void setChannelType(final ChannelType channelType) {
this.channelType = channelType;
}
public final ChannelType getChannelType() {
return this.channelType;
}
public JobID getJobID() {
return this.jobID;
}
public GateID getGateID() {
return this.gateID;
}
// FROM GATE INTERFACE
/**
* Publishes an event.
*
* @param event
* the event to be published
* @throws IOException
* thrown if an error occurs while transmitting the event
* @throws InterruptedException
* thrown if the thread is interrupted while waiting for the event to be published
*/
abstract public void publishEvent(AbstractEvent event) throws IOException, InterruptedException;
/**
* Releases the allocated resources (particularly buffer) of all channels attached to this gate. This method
* should only be called after the respected task has stopped running.
*/
abstract public void releaseAllChannelResources();
/**
* Checks if the gate is closed. The gate is closed if all this associated channels are closed.
*
* @return true if the gate is closed, false otherwise
* @throws IOException
* thrown if any error occurred while closing the gate
* @throws InterruptedException
* thrown if the gate is interrupted while waiting for this operation to complete
*/
abstract public boolean isClosed() throws IOException, InterruptedException;
/**
* Checks if the considered gate is an input gate.
*
* @return true if the considered gate is an input gate, false if it is an output gate
*/
abstract public boolean isInputGate();
}