| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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.apache.giraph.jython; |
| |
| import org.apache.giraph.graph.AbstractComputation; |
| import org.apache.giraph.graph.GraphType; |
| import org.apache.giraph.graph.Language; |
| import org.apache.giraph.graph.Vertex; |
| import org.apache.giraph.jython.wrappers.JythonWritableWrapper; |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableComparable; |
| import org.python.core.PyObject; |
| |
| import com.google.common.base.Preconditions; |
| |
| import java.io.IOException; |
| |
| /** |
| * The {@link org.apache.giraph.graph.Computation} class for using |
| * Jython with Giraph. This class implements the Giraph necessary |
| * interfaces but it actually holds a reference to the |
| * {@link JythonComputation} which does the real work. |
| * |
| * The two classes are linked and together they allow us to coerce Jython types |
| * to Writables. |
| * |
| * @param <I> Vertex ID |
| * @param <V> Vertex value |
| * @param <E> Edge value |
| * @param <M1> Incoming message value |
| * @param <M2> Outgoing message value |
| */ |
| public class JythonGiraphComputation<I extends WritableComparable, |
| V extends Writable, E extends Writable, M1 extends Writable, |
| M2 extends Writable> |
| extends AbstractComputation<I, V, E, M1, M2> { |
| /** The user's computation class */ |
| private final JythonComputation jythonComputation; |
| |
| /** |
| * Constructor |
| * |
| * @param jythonComputation the user's Jython computation |
| */ |
| public JythonGiraphComputation(JythonComputation jythonComputation) { |
| this.jythonComputation = jythonComputation; |
| } |
| |
| @Override public void compute(Vertex<I, V, E> vertex, Iterable<M1> messages) |
| throws IOException { |
| jythonComputation.compute(vertex, messages); |
| } |
| |
| /** |
| * Wrap a vertex id in a {@link WritableComparable} wrapper if necessary |
| * |
| * @param object data to wrap |
| * @return writable value |
| */ |
| public WritableComparable wrapIdIfNecessary(Object object) { |
| return wrapIfNecessary(object, GraphType.VERTEX_ID); |
| } |
| |
| /** |
| * Wrap a user value (IVEMM) in a {@link Writable} wrapper if necessary |
| * |
| * @param object data to wrap |
| * @param graphType type of data (IVEMM) |
| * @param <W> writable type |
| * @return writable value |
| */ |
| public <W extends Writable> W |
| wrapIfNecessary(Object object, GraphType graphType) { |
| if (graphType.interfaceClass().isInstance(object)) { |
| return (W) object; |
| } |
| if (getConf().getValueLanguages().get(graphType) == Language.JYTHON && |
| getConf().getValueNeedsWrappers().get(graphType)) { |
| Preconditions.checkArgument(object instanceof PyObject); |
| return (W) new JythonWritableWrapper((PyObject) object); |
| } else { |
| return (W) object; |
| } |
| } |
| } |