src/main/java/org/apache/bsf/engines/jython/JythonEngine.java - commons-bsf - Git at Google

 /*
  * 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.bsf.engines.jython;

 import java.beans.PropertyChangeEvent;
 import java.io.ByteArrayInputStream;
 import java.util.Vector;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 import org.apache.bsf.BSFDeclaredBean;
 import org.apache.bsf.BSFException;
 import org.apache.bsf.BSFManager;
 import org.apache.bsf.util.BSFEngineImpl;
 import org.apache.bsf.util.BSFFunctions;
 import org.python.core.Py;
 import org.python.core.PyException;
 import org.python.core.PyJavaInstance;
 import org.python.core.PyObject;
 import org.python.core.PySystemState;
 import org.python.util.InteractiveInterpreter;

 /**
  * This is the interface to Jython (http://www.jython.org/) from BSF.
  * It's derived from the JPython 1.x engine
  *
  * @author   Sanjiva Weerawarana
  * @author   Finn Bock <bckfnn@worldonline.dk>
  * @author   Chuck Murcko
  * @author   Sonny To" <son.c.to@gmail.com>, 2006-10-30
  */

 public class JythonEngine extends BSFEngineImpl {
   BSFPythonInterpreter interp;
   private final static Pattern fromRegExp = Pattern.compile("from ([.^\\S]*)");

   /**
    * call the named method of the given object.
    */
   public Object call (Object object, String method, Object[] args)
       throws BSFException {
       try {
           PyObject[] pyargs = Py.EmptyObjects;

           if (args != null) {
               pyargs = new PyObject[args.length];
               for (int i = 0; i < pyargs.length; i++)
                   pyargs[i] = Py.java2py(args[i]);
           }

           if (object != null) {
               PyObject o = Py.java2py(object);
               return unwrap(o.invoke(method, pyargs));
           }

           PyObject m = interp.get(method);

           if (m == null)
               m = interp.eval(method);
           if (m != null) {
               return unwrap(m.__call__(pyargs));
           }

           return null;
       } catch (PyException e) {
           throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
                                   "exception from Jython:\n" + e, e);
       }
   }

   /**
    * Declare a bean
    */
   public void declareBean (BSFDeclaredBean bean) throws BSFException {
 	interp.set (bean.name, bean.bean);
   }

   /**
    * Evaluate an anonymous function (differs from eval() in that apply()
    * handles multiple lines).
    */
   public Object apply (String source, int lineNo, int columnNo,
                        Object funcBody, Vector paramNames,
                        Vector arguments) throws BSFException {
       try {
           /* We wrapper the original script in a function definition, and
            * evaluate the function. A hack, no question, but it allows
            * apply() to pretend to work on Jython.
            */
           StringBuffer script = new StringBuffer(byteify(funcBody.toString()));
           int index = 0;
           script.insert(0, "def bsf_temp_fn():\n");

           while (index < script.length()) {
               if (script.charAt(index) == '\n') {
                   script.insert(index+1, '\t');
               }
               index++;
           }

           String scriptStr = script.toString ();
           importPackage(scriptStr);
           interp.exec (scriptStr);

           Object result = interp.eval ("bsf_temp_fn()");

           if (result instanceof PyJavaInstance)
               result = ((PyJavaInstance)result).__tojava__(Object.class);
           return result;
       } catch (PyException e) {
           throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
                                   "exception from Jython:\n" + e, e);
       }
   }

   /**
    * Evaluate an expression.
    */
   public Object eval (String source, int lineNo, int columnNo,
 		      Object script) throws BSFException {
 	try {
 	  String scriptStr = byteify(script.toString ());
 	  importPackage(scriptStr);
 	  Object result = interp.eval (scriptStr);
 	  if (result instanceof PyJavaInstance)
 		result = ((PyJavaInstance)result).__tojava__(Object.class);
 	  return result;
 	} catch (PyException e) {
 	  throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
 			      "exception from Jython:\n" + e, e);
 	}
   }

   /**
    * Execute a script.
    */
   public void exec (String source, int lineNo, int columnNo,
 		    Object script) throws BSFException {
 	try {
 	  String scriptStr = byteify(script.toString());
 	  importPackage(scriptStr);
 	  interp.exec (scriptStr);
 	} catch (PyException e) {
 	  throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
 			      "exception from Jython:\n" + e, e);
 	}
   }

   private void importPackage(String script) {
 	Matcher matcher = fromRegExp.matcher(script);
 	while (matcher.find()) {
 		String packageName = matcher.group(1);
 		PySystemState.add_package(packageName);
 	}
   }

   /**
    * Execute script code, emulating console interaction.
    */
   public void iexec (String source, int lineNo, int columnNo,
                      Object script) throws BSFException {
       String scriptStr = byteify(script.toString());
       importPackage(scriptStr);
       int newline = scriptStr.indexOf("\n");

       if (newline > -1)
           scriptStr = scriptStr.substring(0, newline);

       try {
           if (interp.buffer.length() > 0)
               interp.buffer.append("\n");
           interp.buffer.append(scriptStr);
           if (!(interp.runsource(interp.buffer.toString())))
               interp.resetbuffer();
       } catch (PyException e) {
           interp.resetbuffer();
           throw new BSFException(BSFException.REASON_EXECUTION_ERROR,
                                  "exception from Jython:\n" + e, e);
       }
   }

   /**
    * Initialize the engine.
    */
   public void initialize (BSFManager mgr, String lang,
 						  Vector declaredBeans) throws BSFException {
 	super.initialize (mgr, lang, declaredBeans);

 	// create an interpreter
 	interp = new BSFPythonInterpreter ();

     // ensure that output and error streams are re-directed correctly
     interp.setOut(System.out);
     interp.setErr(System.err);

 	// register the mgr with object name "bsf"
 	interp.set ("bsf", new BSFFunctions (mgr, this));

     // Declare all declared beans to the interpreter
 	int size = declaredBeans.size ();
 	for (int i = 0; i < size; i++) {
 	  declareBean ((BSFDeclaredBean) declaredBeans.elementAt (i));
 	}
   }

   /**
    * Undeclare a previously declared bean.
    */
   public void undeclareBean (BSFDeclaredBean bean) throws BSFException {
 	interp.set (bean.name, null);
   }

   public Object unwrap(PyObject result) {
 	if (result != null) {
 	   Object ret = result.__tojava__(Object.class);
 	   if (ret != Py.NoConversion)
 		  return ret;
 	}
 	return result;
   }

   private String byteify (String orig) {
       // Ugh. Jython likes to be fed bytes, rather than the input string.
       ByteArrayInputStream bais =
           new ByteArrayInputStream(orig.getBytes());
       StringBuffer s = new StringBuffer();
       int c;

       while ((c = bais.read()) >= 0) {
           s.append((char)c);
       }

       return s.toString();
   }

   private class BSFPythonInterpreter extends InteractiveInterpreter {

       public BSFPythonInterpreter() {
       }

       // Override runcode so as not to print the stack dump
       public void runcode(PyObject code) {
           try {
               this.exec(code);
           } catch (PyException exc) {
               throw exc;
           }
       }
   }


   public void propertyChange(PropertyChangeEvent e) {
 	  super.propertyChange(e);
 	  String name = e.getPropertyName();
       Object value = e.getNewValue();
       if (name.equals("classLoader")) {
 		Py.getSystemState().setClassLoader((ClassLoader) value);
       }

   }
 }
	/*
	* 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.bsf.engines.jython;

	import java.beans.PropertyChangeEvent;
	import java.io.ByteArrayInputStream;
	import java.util.Vector;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	import org.apache.bsf.BSFDeclaredBean;
	import org.apache.bsf.BSFException;
	import org.apache.bsf.BSFManager;
	import org.apache.bsf.util.BSFEngineImpl;
	import org.apache.bsf.util.BSFFunctions;
	import org.python.core.Py;
	import org.python.core.PyException;
	import org.python.core.PyJavaInstance;
	import org.python.core.PyObject;
	import org.python.core.PySystemState;
	import org.python.util.InteractiveInterpreter;

	/**
	* This is the interface to Jython (http://www.jython.org/) from BSF.
	* It's derived from the JPython 1.x engine
	*
	* @author Sanjiva Weerawarana
	* @author Finn Bock <bckfnn@worldonline.dk>
	* @author Chuck Murcko
	* @author Sonny To" <son.c.to@gmail.com>, 2006-10-30
	*/

	public class JythonEngine extends BSFEngineImpl {
	BSFPythonInterpreter interp;
	private final static Pattern fromRegExp = Pattern.compile("from ([.^\\S]*)");

	/**
	* call the named method of the given object.
	*/
	public Object call (Object object, String method, Object[] args)
	throws BSFException {
	try {
	PyObject[] pyargs = Py.EmptyObjects;

	if (args != null) {
	pyargs = new PyObject[args.length];
	for (int i = 0; i < pyargs.length; i++)
	pyargs[i] = Py.java2py(args[i]);
	}

	if (object != null) {
	PyObject o = Py.java2py(object);
	return unwrap(o.invoke(method, pyargs));
	}

	PyObject m = interp.get(method);

	if (m == null)
	m = interp.eval(method);
	if (m != null) {
	return unwrap(m.__call__(pyargs));
	}

	return null;
	} catch (PyException e) {
	throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
	"exception from Jython:\n" + e, e);
	}
	}

	/**
	* Declare a bean
	*/
	public void declareBean (BSFDeclaredBean bean) throws BSFException {
	interp.set (bean.name, bean.bean);
	}

	/**
	* Evaluate an anonymous function (differs from eval() in that apply()
	* handles multiple lines).
	*/
	public Object apply (String source, int lineNo, int columnNo,
	Object funcBody, Vector paramNames,
	Vector arguments) throws BSFException {
	try {
	/* We wrapper the original script in a function definition, and
	* evaluate the function. A hack, no question, but it allows
	* apply() to pretend to work on Jython.
	*/
	StringBuffer script = new StringBuffer(byteify(funcBody.toString()));
	int index = 0;
	script.insert(0, "def bsf_temp_fn():\n");

	while (index < script.length()) {
	if (script.charAt(index) == '\n') {
	script.insert(index+1, '\t');
	}
	index++;
	}

	String scriptStr = script.toString ();
	importPackage(scriptStr);
	interp.exec (scriptStr);

	Object result = interp.eval ("bsf_temp_fn()");

	if (result instanceof PyJavaInstance)
	result = ((PyJavaInstance)result).__tojava__(Object.class);
	return result;
	} catch (PyException e) {
	throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
	"exception from Jython:\n" + e, e);
	}
	}

	/**
	* Evaluate an expression.
	*/
	public Object eval (String source, int lineNo, int columnNo,
	Object script) throws BSFException {
	try {
	String scriptStr = byteify(script.toString ());
	importPackage(scriptStr);
	Object result = interp.eval (scriptStr);
	if (result instanceof PyJavaInstance)
	result = ((PyJavaInstance)result).__tojava__(Object.class);
	return result;
	} catch (PyException e) {
	throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
	"exception from Jython:\n" + e, e);
	}
	}

	/**
	* Execute a script.
	*/
	public void exec (String source, int lineNo, int columnNo,
	Object script) throws BSFException {
	try {
	String scriptStr = byteify(script.toString());
	importPackage(scriptStr);
	interp.exec (scriptStr);
	} catch (PyException e) {
	throw new BSFException (BSFException.REASON_EXECUTION_ERROR,
	"exception from Jython:\n" + e, e);
	}
	}

	private void importPackage(String script) {
	Matcher matcher = fromRegExp.matcher(script);
	while (matcher.find()) {
	String packageName = matcher.group(1);
	PySystemState.add_package(packageName);
	}
	}

	/**
	* Execute script code, emulating console interaction.
	*/
	public void iexec (String source, int lineNo, int columnNo,
	Object script) throws BSFException {
	String scriptStr = byteify(script.toString());
	importPackage(scriptStr);
	int newline = scriptStr.indexOf("\n");

	if (newline > -1)
	scriptStr = scriptStr.substring(0, newline);

	try {
	if (interp.buffer.length() > 0)
	interp.buffer.append("\n");
	interp.buffer.append(scriptStr);
	if (!(interp.runsource(interp.buffer.toString())))
	interp.resetbuffer();
	} catch (PyException e) {
	interp.resetbuffer();
	throw new BSFException(BSFException.REASON_EXECUTION_ERROR,
	"exception from Jython:\n" + e, e);
	}
	}

	/**
	* Initialize the engine.
	*/
	public void initialize (BSFManager mgr, String lang,
	Vector declaredBeans) throws BSFException {
	super.initialize (mgr, lang, declaredBeans);

	// create an interpreter
	interp = new BSFPythonInterpreter ();

	// ensure that output and error streams are re-directed correctly
	interp.setOut(System.out);
	interp.setErr(System.err);

	// register the mgr with object name "bsf"
	interp.set ("bsf", new BSFFunctions (mgr, this));

	// Declare all declared beans to the interpreter
	int size = declaredBeans.size ();
	for (int i = 0; i < size; i++) {
	declareBean ((BSFDeclaredBean) declaredBeans.elementAt (i));
	}
	}

	/**
	* Undeclare a previously declared bean.
	*/
	public void undeclareBean (BSFDeclaredBean bean) throws BSFException {
	interp.set (bean.name, null);
	}

	public Object unwrap(PyObject result) {
	if (result != null) {
	Object ret = result.__tojava__(Object.class);
	if (ret != Py.NoConversion)
	return ret;
	}
	return result;
	}

	private String byteify (String orig) {
	// Ugh. Jython likes to be fed bytes, rather than the input string.
	ByteArrayInputStream bais =
	new ByteArrayInputStream(orig.getBytes());
	StringBuffer s = new StringBuffer();
	int c;

	while ((c = bais.read()) >= 0) {
	s.append((char)c);
	}

	return s.toString();
	}

	private class BSFPythonInterpreter extends InteractiveInterpreter {

	public BSFPythonInterpreter() {
	}

	// Override runcode so as not to print the stack dump
	public void runcode(PyObject code) {
	try {
	this.exec(code);
	} catch (PyException exc) {
	throw exc;
	}
	}
	}


	public void propertyChange(PropertyChangeEvent e) {
	super.propertyChange(e);
	String name = e.getPropertyName();
	Object value = e.getNewValue();
	if (name.equals("classLoader")) {
	Py.getSystemState().setClassLoader((ClassLoader) value);
	}

	}
	}