/*

  * 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.factories;

 import org.apache.giraph.conf.ClassConfOption;

 import org.apache.giraph.conf.GiraphConfigurationSettable;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;

 import org.apache.giraph.conf.StrConfOption;

 import org.apache.giraph.factories.ValueFactory;

 import org.apache.giraph.graph.GraphType;

 import org.apache.giraph.jython.JythonOptions;

 import org.apache.giraph.jython.JythonUtils;

 import org.apache.giraph.jython.wrappers.JythonWritableWrapper;

 import org.apache.hadoop.conf.Configuration;

 import org.apache.hadoop.io.Writable;

 import org.apache.log4j.Logger;

 import org.python.core.PyObject;

 /**

  * Base class for Jython factories. These factories are used to create user's

  * graph value types (IVEMM).

  *

  * @param <W> writable type

  */

 public abstract class JythonFactoryBase<W extends Writable>

     implements ValueFactory<W>, GiraphConfigurationSettable {

   /** Logger */

   private static final Logger LOG = Logger.getLogger(JythonFactoryBase.class);

   /** Name of class in Jython implementing Vertex ID */

   private String jythonClassName;

   /** Whether the Jython type needs a wrapper */

   private boolean useWrapper;

   /**

    * Get the options associated with this graph type

    *

    * @return options

    */

   public abstract JythonOptions.JythonGraphTypeOptions getOptions();

   /**

    * Get the graph type this factory is meant for

    *

    * @return GraphType

    */

   public GraphType getGraphType() {

     return getOptions().getGraphType();

   }

   /**

    * The {@link org.apache.hadoop.conf.Configuration} option for setting the

    * Jython class name in this factory implementation.

    *

    * @return {@link org.apache.giraph.conf.StrConfOption}

    */

   public StrConfOption jythonClassNameOption() {

     return getOptions().getJythonClassNameOption();

   }

   /**

    * The interface class for the value type.

    * For Vertex ID this is {@link org.apache.hadoop.io.WritableComparable}, for

    * others this is {@link org.apache.hadoop.io.Writable}

    *

    * @return interface class for the value type

    */

   public Class<? extends Writable> writableValueClass() {

     return getGraphType().interfaceClass();

   }

   @Override

   public void setConf(

       ImmutableClassesGiraphConfiguration conf) {

     jythonClassName = jythonClassNameOption().get(conf);

     useWrapper = conf.getValueNeedsWrappers().get(getGraphType());

   }

   /**

    * Instantiate a new value Jython object.

    *

    * @return new value object

    */

   public Writable newJythonClassInstance() {

     if (useWrapper) {

       PyObject jythonObj = JythonUtils.newInstance(jythonClassName);

       JythonWritableWrapper wrapper = new JythonWritableWrapper(jythonObj);

       return wrapper;

     } else {

       return JythonUtils.newInstance(jythonClassName, writableValueClass());

     }

   }

   /**

    * Use this factory in the {@link org.apache.hadoop.conf.Configuration}

    *

    * @param conf {@link org.apache.hadoop.conf.Configuration}

    * @param jythonClassName Name of Jython class implementing value type

    */

   public void useThisFactory(Configuration conf, String jythonClassName) {

     if (LOG.isInfoEnabled()) {

       LOG.info("useThisFactory: Setting up Jython factory for " +

           getGraphType() + " reading " + " using Jython type " +

           jythonClassName);

     }

     ClassConfOption factoryOption = getGraphType().factoryClassOption();

     factoryOption.set(conf, getClass());

     jythonClassNameOption().set(conf, jythonClassName);

   }

 }