/*
* 2012-3 Red Hat Inc. and/or its affiliates and other contributors.
*
* 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 org.overlord.rtgov.ep.mvel;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.mvel2.MVEL;
import org.overlord.rtgov.ep.EventProcessor;
import org.overlord.rtgov.internal.ep.DefaultEPContext;
/**
* This class represents the MVEL implementation of the Event
* Processor.
*
*/
public class MVELEventProcessor extends EventProcessor {
private static final Logger LOG=Logger.getLogger(MVELEventProcessor.class.getName());
private DefaultEPContext _context=null;
private String _script=null;
private Object _scriptExpression=null;
/**
* {@inheritDoc}
*/
public void init() throws Exception {
super.init();
// Load the script
java.io.InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream(_script);
if (is == null) {
throw new Exception("Unable to locate MVEL script '"+_script+"'");
} else {
byte[] b=new byte[is.available()];
is.read(b);
is.close();
// Compile expression
_scriptExpression = MVEL.compileExpression(new String(b));
if (LOG.isLoggable(Level.FINE)) {
LOG.fine("Initialized script="+_script
+" compiled="+_scriptExpression);
}
}
_context = new DefaultEPContext(getServices(), getParameters());
}
/**
* This method returns the script.
*
* @return The script
*/
public String getScript() {
return (_script);
}
/**
* This method sets the script.
*
* @param script The script
*/
public void setScript(String script) {
_script = script;
}
/**
* {@inheritDoc}
*/
public java.io.Serializable process(String source,
java.io.Serializable event, int retriesLeft) throws Exception {
java.io.Serializable ret=null;
if (LOG.isLoggable(Level.FINEST)) {
LOG.finest("Process event '"+event+" from source '"+source
+"' on MVEL Event Processor '"+getScript()
+"'");
}
if (_scriptExpression != null) {
java.util.Map<String,Object> vars=
new java.util.HashMap<String, Object>();
vars.put("source", source);
vars.put("event", event);
vars.put("retriesLeft", retriesLeft);
vars.put("epc", _context);
synchronized (this) {
_context.handle(null);
MVEL.executeExpression(_scriptExpression, vars);
ret = (java.io.Serializable)_context.getResult();
}
if (ret instanceof Exception) {
throw (Exception)ret;
}
}
return (ret);
}
}