/***********************************************************************************************************************
* 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.spargel.java.record;
import java.io.IOException;
import java.util.Iterator;
import eu.stratosphere.api.common.aggregators.AggregatorRegistry;
import eu.stratosphere.api.common.operators.Operator;
import eu.stratosphere.api.java.record.operators.DeltaIteration;
import eu.stratosphere.api.java.record.functions.CoGroupFunction;
import eu.stratosphere.api.java.record.functions.FunctionAnnotation.ConstantFieldsFirst;
import eu.stratosphere.api.java.record.operators.CoGroupOperator;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.types.Key;
import eu.stratosphere.types.Record;
import eu.stratosphere.types.Value;
import eu.stratosphere.util.Collector;
import eu.stratosphere.util.InstantiationUtil;
import eu.stratosphere.util.ReflectionUtil;
public class SpargelIteration {
private static final String DEFAULT_NAME = "<unnamed vertex-centric iteration>";
private final DeltaIteration iteration;
private final Class<? extends Key<?>> vertexKey;
private final Class<? extends Value> vertexValue;
private final Class<? extends Value> messageType;
private final Class<? extends Value> edgeValue;
private final CoGroupOperator vertexUpdater;
private final CoGroupOperator messager;
// ----------------------------------------------------------------------------------
public <VertexKey extends Key<VertexKey>, VertexValue extends Value, Message extends Value, EdgeValue extends Value>
SpargelIteration(MessagingFunction<VertexKey, VertexValue, Message, EdgeValue> mf,
VertexUpdateFunction<VertexKey, VertexValue, Message> uf)
{
this(mf, uf, DEFAULT_NAME);
}
public <VertexKey extends Key<VertexKey>, VertexValue extends Value, Message extends Value, EdgeValue extends Value> SpargelIteration(
MessagingFunction<VertexKey, VertexValue, Message, EdgeValue> mf, VertexUpdateFunction<VertexKey, VertexValue, Message> uf,
String name)
{
// get the types
this.vertexKey = ReflectionUtil.getTemplateType1(mf.getClass());
this.vertexValue = ReflectionUtil.getTemplateType2(mf.getClass());
this.messageType = ReflectionUtil.getTemplateType3(mf.getClass());
this.edgeValue = ReflectionUtil.getTemplateType4(mf.getClass());
if (vertexKey == null || vertexValue == null || messageType == null || edgeValue == null) {
throw new RuntimeException();
}
// instantiate the data flow
this.iteration = new DeltaIteration(0, name);
this.messager = CoGroupOperator.builder(MessagingDriver.class, vertexKey, 0, 0)
.input2(iteration.getWorkset())
.name("Message Sender")
.build();
this.vertexUpdater = CoGroupOperator.builder(VertexUpdateDriver.class, vertexKey, 0, 0)
.input1(messager)
.input2(iteration.getSolutionSet())
.name("Vertex Updater")
.build();
iteration.setNextWorkset(vertexUpdater);
iteration.setSolutionSetDelta(vertexUpdater);
// parameterize the data flow
try {
Configuration vertexUdfParams = vertexUpdater.getParameters();
InstantiationUtil.writeObjectToConfig(uf, vertexUdfParams, VertexUpdateDriver.UDF_PARAM);
vertexUdfParams.setClass(VertexUpdateDriver.KEY_PARAM, vertexKey);
vertexUdfParams.setClass(VertexUpdateDriver.VALUE_PARAM, vertexValue);
vertexUdfParams.setClass(VertexUpdateDriver.MESSAGE_PARAM, messageType);
Configuration messageUdfParams = messager.getParameters();
InstantiationUtil.writeObjectToConfig(mf, messageUdfParams, MessagingDriver.UDF_PARAM);
messageUdfParams.setClass(MessagingDriver.KEY_PARAM, vertexKey);
messageUdfParams.setClass(MessagingDriver.VALUE_PARAM, vertexValue);
messageUdfParams.setClass(MessagingDriver.MESSAGE_PARAM, messageType);
messageUdfParams.setClass(MessagingDriver.EDGE_PARAM, edgeValue);
}
catch (IOException e) {
throw new RuntimeException("Could not serialize the UDFs for distribution" +
(e.getMessage() == null ? '.' : ": " + e.getMessage()), e);
}
}
// ----------------------------------------------------------------------------------
// inputs and outputs
// ----------------------------------------------------------------------------------
public void setVertexInput(Operator<Record> c) {
this.iteration.setInitialSolutionSet(c);
this.iteration.setInitialWorkset(c);
}
public void setEdgesInput(Operator<Record> c) {
this.messager.setFirstInput(c);
}
public Operator<?> getOutput() {
return this.iteration;
}
public void setDegreeOfParallelism(int dop) {
this.iteration.setDegreeOfParallelism(dop);
}
public void setNumberOfIterations(int iterations) {
this.iteration.setMaximumNumberOfIterations(iterations);
}
public AggregatorRegistry getAggregators() {
return this.iteration.getAggregators();
}
// --------------------------------------------------------------------------------------------
// Wrapping UDFs
// --------------------------------------------------------------------------------------------
@ConstantFieldsFirst(0)
public static final class VertexUpdateDriver<K extends Key<K>, V extends Value, M extends Value> extends CoGroupFunction {
private static final long serialVersionUID = 1L;
private static final String UDF_PARAM = "spargel.udf";
private static final String KEY_PARAM = "spargel.key-type";
private static final String VALUE_PARAM = "spargel.value-type";
private static final String MESSAGE_PARAM = "spargel.message-type";
private VertexUpdateFunction<K, V, M> vertexUpdateFunction;
private K vertexKey;
private V vertexValue;
private MessageIterator<M> messageIter;
@Override
public void coGroup(Iterator<Record> messages, Iterator<Record> vertex, Collector<Record> out) throws Exception {
if (vertex.hasNext()) {
Record first = vertex.next();
first.getFieldInto(0, vertexKey);
first.getFieldInto(1, vertexValue);
messageIter.setSource(messages);
vertexUpdateFunction.setOutput(first, out);
vertexUpdateFunction.updateVertex(vertexKey, vertexValue, messageIter);
} else {
if (messages.hasNext()) {
String message = "Target vertex does not exist!.";
try {
Record next = messages.next();
next.getFieldInto(0, vertexKey);
message = "Target vertex '" + vertexKey + "' does not exist!.";
} catch (Throwable t) {}
throw new Exception(message);
} else {
throw new Exception();
}
}
}
@SuppressWarnings("unchecked")
@Override
public void open(Configuration parameters) throws Exception {
// instantiate only the first time
if (vertexUpdateFunction == null) {
Class<K> vertexKeyClass = parameters.getClass(KEY_PARAM, null, Key.class);
Class<V> vertexValueClass = parameters.getClass(VALUE_PARAM, null, Value.class);
Class<M> messageClass = parameters.getClass(MESSAGE_PARAM, null, Value.class);
vertexKey = InstantiationUtil.instantiate(vertexKeyClass, Key.class);
vertexValue = InstantiationUtil.instantiate(vertexValueClass, Value.class);
messageIter = new MessageIterator<M>(InstantiationUtil.instantiate(messageClass, Value.class));
try {
this.vertexUpdateFunction = (VertexUpdateFunction<K, V, M>) InstantiationUtil.readObjectFromConfig(parameters, UDF_PARAM, parameters.getClassLoader());
} catch (Exception e) {
String message = e.getMessage() == null ? "." : ": " + e.getMessage();
throw new Exception("Could not instantiate VertexUpdateFunction" + message, e);
}
this.vertexUpdateFunction.init(getIterationRuntimeContext());
this.vertexUpdateFunction.setup(parameters);
}
this.vertexUpdateFunction.preSuperstep();
}
@Override
public void close() throws Exception {
this.vertexUpdateFunction.postSuperstep();
}
}
public static final class MessagingDriver<K extends Key<K>, V extends Value, M extends Value, E extends Value> extends CoGroupFunction {
private static final long serialVersionUID = 1L;
private static final String UDF_PARAM = "spargel.udf";
private static final String KEY_PARAM = "spargel.key-type";
private static final String VALUE_PARAM = "spargel.value-type";
private static final String MESSAGE_PARAM = "spargel.message-type";
private static final String EDGE_PARAM = "spargel.edge-value";
private MessagingFunction<K, V, M, E> messagingFunction;
private K vertexKey;
private V vertexValue;
@Override
public void coGroup(Iterator<Record> edges, Iterator<Record> state, Collector<Record> out) throws Exception {
if (state.hasNext()) {
Record first = state.next();
first.getFieldInto(0, vertexKey);
first.getFieldInto(1, vertexValue);
messagingFunction.set(edges, out);
messagingFunction.sendMessages(vertexKey, vertexValue);
}
}
@SuppressWarnings("unchecked")
@Override
public void open(Configuration parameters) throws Exception {
// instantiate only the first time
if (messagingFunction == null) {
Class<K> vertexKeyClass = parameters.getClass(KEY_PARAM, null, Key.class);
Class<V> vertexValueClass = parameters.getClass(VALUE_PARAM, null, Value.class);
// Class<M> messageClass = parameters.getClass(MESSAGE_PARAM, null, Value.class);
Class<E> edgeClass = parameters.getClass(EDGE_PARAM, null, Value.class);
vertexKey = InstantiationUtil.instantiate(vertexKeyClass, Key.class);
vertexValue = InstantiationUtil.instantiate(vertexValueClass, Value.class);
K edgeKeyHolder = InstantiationUtil.instantiate(vertexKeyClass, Key.class);
E edgeValueHolder = InstantiationUtil.instantiate(edgeClass, Value.class);
try {
this.messagingFunction = (MessagingFunction<K, V, M, E>) InstantiationUtil.readObjectFromConfig(parameters, UDF_PARAM, parameters.getClassLoader());
} catch (Exception e) {
String message = e.getMessage() == null ? "." : ": " + e.getMessage();
throw new Exception("Could not instantiate MessagingFunction" + message, e);
}
this.messagingFunction.init(getIterationRuntimeContext(), edgeKeyHolder, edgeValueHolder);
this.messagingFunction.setup(parameters);
}
this.messagingFunction.preSuperstep();
}
@Override
public void close() throws Exception {
this.messagingFunction.postSuperstep();
}
}
}