/***********************************************************************************************************************
* 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.api;
import java.io.IOException;
import eu.stratosphere.core.io.IOReadableWritable;
import eu.stratosphere.runtime.io.gates.InputChannelResult;
import eu.stratosphere.nephele.template.AbstractOutputTask;
import eu.stratosphere.nephele.template.AbstractTask;
public class MutableRecordReader<T extends IOReadableWritable> extends AbstractSingleGateRecordReader<T> implements MutableReader<T> {
private boolean endOfStream;
/**
* Constructs a new mutable record reader and registers a new input gate with the application's environment.
*
* @param taskBase The application that instantiated the record reader.
*/
public MutableRecordReader(final AbstractTask taskBase) {
super(taskBase);
}
/**
* Constructs a new record reader and registers a new input gate with the application's environment.
*
* @param outputBase The application that instantiated the record reader.
*/
public MutableRecordReader(final AbstractOutputTask outputBase) {
super(outputBase);
}
/**
* Constructs a new record reader and registers a new input gate with the application's environment.
*
* @param taskBase
* the application that instantiated the record reader
* @param inputGateID
* The ID of the input gate that the reader reads from.
*/
public MutableRecordReader(final AbstractTask taskBase, final int inputGateID) {
super(taskBase);
}
/**
* Constructs a new record reader and registers a new input gate with the application's environment.
*
* @param outputBase
* the application that instantiated the record reader
* @param inputGateID
* The ID of the input gate that the reader reads from.
*/
public MutableRecordReader(final AbstractOutputTask outputBase, final int inputGateID) {
super(outputBase);
}
// --------------------------------------------------------------------------------------------
@Override
public boolean next(final T target) throws IOException, InterruptedException {
if (this.endOfStream) {
return false;
}
while (true) {
InputChannelResult result = this.inputGate.readRecord(target);
switch (result) {
case INTERMEDIATE_RECORD_FROM_BUFFER:
case LAST_RECORD_FROM_BUFFER:
return true;
case END_OF_SUPERSTEP:
if (incrementEndOfSuperstepEventAndCheck()) {
return false; // end of the superstep
}
else {
break; // fall through and wait for next record/event
}
case TASK_EVENT:
handleEvent(this.inputGate.getCurrentEvent());
break; // fall through to get next record
case END_OF_STREAM:
this.endOfStream = true;
return false;
default:
; // fall through to get next record
}
}
}
@Override
public boolean isInputClosed() {
return this.endOfStream;
}
@Override
public void setIterative(int numEventsUntilEndOfSuperstep) {
// sanity check for debug purposes
if (numEventsUntilEndOfSuperstep != getNumberOfInputChannels()) {
throw new IllegalArgumentException("Number of events till end of superstep is different from the number of input channels.");
}
super.setIterative(numEventsUntilEndOfSuperstep);
}
}