PythonActivityScriptWrapper.java

/*
 * Copyright (C) 2012 Google Inc.
 *
 * 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 interactivespaces.service.script.internal.python;

import interactivespaces.InteractiveSpacesException;
import interactivespaces.activity.Activity;
import interactivespaces.activity.ActivityFilesystem;
import interactivespaces.activity.execution.ActivityExecutionContext;
import interactivespaces.configuration.Configuration;
import interactivespaces.service.script.ActivityScriptWrapper;
import interactivespaces.service.script.ScriptActivityExecutionContext;
import interactivespaces.service.script.ScriptSource;

import org.python.core.Py;
import org.python.core.PyException;
import org.python.core.PyObject;
import org.python.core.PySystemState;
import org.python.util.PythonInterpreter;

import java.io.File;

/**
 * An {@link ActivityScriptWrapper} for python scripts.
 *
 * @author Keith M. Hughes
 */
public class PythonActivityScriptWrapper implements ActivityScriptWrapper {

  /**
   * Name of the object being extracted.
   */
  private String objectName;

  /**
   * The contents of the script.
   */
  private ScriptSource scriptSource;

  /**
   * File system for the activity
   */
  private ActivityFilesystem activityFilesystem;

  /**
   * Configuration for the activity script.
   */
  private Configuration configuration;

  public PythonActivityScriptWrapper(String objectName, ScriptSource scriptSource,
      ActivityFilesystem activityFilesystem, Configuration configuration) {
    this.objectName = objectName;
    this.scriptSource = scriptSource;
    this.activityFilesystem = activityFilesystem;
    this.configuration = configuration;
  }

  @Override
  public Activity newInstance() {
    try {
      PythonInterpreter interp = PythonInterpreter.threadLocalStateInterpreter(null);

      // If script dir in the activity install, include at beginning of
      // path.
      File scriptDir = new File(activityFilesystem.getInstallDirectory(), "lib/python");
      if (scriptDir.exists()) {
        if (scriptDir.canRead()) {
          PySystemState systemState = interp.getSystemState();
          systemState.path.add(0, Py.newString(scriptDir.getAbsolutePath()));
        }
      }

      String script = scriptSource.getScriptContents();
      interp.exec(script);

      PyObject cls = interp.get(objectName);
      if (cls == null)
        throw new InteractiveSpacesException(String.format("No callable class named %s in %s",
            objectName, script));

      PyObject processingUnit = cls.__call__();
      Object o = processingUnit.__tojava__(Activity.class);
      if (o == Py.NoConversion)
        throw new InteractiveSpacesException(String.format(
            "The value with name %s must implement %s", objectName, Activity.class.getName()));

      return (Activity) o;
    } catch (PyException e) {
      e.printStackTrace();
      throw new InteractiveSpacesException("Could not create Jython Interactive Spaces activity ",
          e);
    }
  }

  @Override
  public ActivityExecutionContext newExecutionContext() {
    return new ScriptActivityExecutionContext(PythonActivityScriptWrapper.class.getClassLoader());
  }
}