package org.jacorb.notification.filter.bsh;
/*
* JacORB - a free Java ORB
*
* Copyright (C) 1997-2003 Gerald Brose.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
import java.util.Date;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.jacorb.notification.MessageFactory;
import org.jacorb.notification.filter.AbstractFilter;
import org.jacorb.notification.filter.EvaluationContext;
import org.jacorb.notification.filter.EvaluationException;
import org.jacorb.notification.filter.EvaluationResult;
import org.jacorb.notification.filter.FilterConstraint;
import org.jacorb.notification.interfaces.EvaluationContextFactory;
import org.jacorb.notification.interfaces.Message;
import org.omg.CosNotifyFilter.ConstraintExp;
import org.omg.PortableServer.POA;
import bsh.EvalError;
import bsh.Interpreter;
/**
* This is an example of an custom Filter plugin.
* to make this grammar available to the FilterFactory you have
* to add an entry with the prefix jacorb.notification.filter.plugin to jacorb.properties.
* The entry must have the following form:
*
* <code>jacorb.notification.filter.plugin.GRAMMAR_NAME=CLASSNAME</code>
* <br>
* to make this grammar available one had to add the following entry to jacorb.properties:
* <code>jacorb.notification.filter.plugin.BSH=org.jacorb.notification.filter.bsh.BSHFilter</code>
*
* @author Alphonse Bendt
* @version $Id: BSHFilter.java,v 1.6 2006/03/05 13:48:19 alphonse.bendt Exp $
*/
public class BSHFilter extends AbstractFilter
{
public static final String CONSTRAINT_GRAMMAR = "BSH";
/**
* as instances of this class will be created using picocontainer the class
* can specify its dependencies in the constructor. picocontainer will fill
* in the appropiate values (as long as they are registered).
*/
public BSHFilter(Configuration config, EvaluationContextFactory evaluationContextFactory,
MessageFactory messageFactory, POA poa) throws ConfigurationException
{
super(config, evaluationContextFactory, messageFactory, poa);
}
public String constraint_grammar()
{
return CONSTRAINT_GRAMMAR;
}
public FilterConstraint newFilterConstraint(ConstraintExp constraintExp)
{
return new BSHFilterConstraint(constraintExp);
}
private static class BSHFilterConstraint implements FilterConstraint
{
private final String constraint_;
BSHFilterConstraint(ConstraintExp constraintExp)
{
constraint_ = constraintExp.constraint_expr;
}
public EvaluationResult evaluate(EvaluationContext context, Message message)
throws EvaluationException
{
try
{
Interpreter _interpreter = new Interpreter();
// TODO import useful stuff
// predefine useful functions?
_interpreter.eval("import org.omg.CORBA.*;");
_interpreter.set("event", message.toAny());
_interpreter.set("date", new Date());
_interpreter.set("constraint", constraint_);
Object _result = _interpreter.eval(constraint_);
if (_result == null)
{
return EvaluationResult.BOOL_FALSE;
}
if (_result instanceof Boolean)
{
if (_result.equals(Boolean.TRUE))
{
return EvaluationResult.BOOL_TRUE;
}
return EvaluationResult.BOOL_FALSE;
}
if (_result instanceof String)
{
if ("".equals(_result))
{
return EvaluationResult.BOOL_FALSE;
}
return EvaluationResult.BOOL_TRUE;
}
return EvaluationResult.BOOL_TRUE;
} catch (EvalError e)
{
throw new EvaluationException(e);
}
}
}
}