/*
 *
 * $author: $
 *
 * $Date: $
 *
 * $Archive: $
 *
 * $Log: $
 */
package de.fs24.services.wfms.actionhandler;

import java.util.Iterator;
import java.util.Map;

import org.apache.log4j.Logger;
import org.jbpm.ConfigurationException;
import org.jbpm.delegation.Configurable;
import org.jbpm.delegation.DecisionHandler;
import org.jbpm.delegation.ExecutionContext;
import org.jbpm.model.execution.Token;

import bsh.EvalError;
import bsh.Interpreter;


/**
 * Integrates beanshell scripts into a DecisionHandler.
 */
public class BeanShellDecisionHandler implements DecisionHandler, Configurable
{
    private static final Logger logger = Logger.getLogger(BeanShellDecisionHandler.class);
    
    String beanShellScript = null;
    
    public void configure(String config) throws ConfigurationException
    {
        this.beanShellScript = config;
    }

    /**
     * 
     */
    public BeanShellDecisionHandler()
    {
        super();
    }

    /**
     * Integrates the use of beanshell into an {@link org.jbpm.delegation.DecisionHandler}. All
     * workflow variables in the variables Map that use a java.lang.String-Object as a 
     * key are passed to the beanshell script and can be used there.<br>
     * The beanshell script must define a variable named transition that is set to the
     * transition that should be taken. The method decide returns this variable's value.
     * 
     * @param executionContext jbpm ExecutionContext
     */
    public String decide(ExecutionContext executionContext)
    {
        Interpreter i = new Interpreter();
        Token currentToken = executionContext.getToken();
        
        // Uebertrage Inhalte der Workflow-Variablen (nur solche mit Key-Typ String!)
        Map variables = executionContext.getExecutionService().getVariables(currentToken.getId());
        for (Iterator iter = variables.entrySet().iterator(); iter.hasNext();)
        {
            Map.Entry mapEntry = (Map.Entry) iter.next();
            if (mapEntry.getKey() instanceof String)
            {
                logger.debug("var: " + mapEntry.getKey() + "=" + mapEntry.getValue());
                try
                {
                    i.set((String)mapEntry.getKey(), mapEntry.getValue());
                }
                catch (EvalError e)
                {
                    logger.error("Fehler beim Setzen von BeanShell var " + mapEntry);
                    throw new RuntimeException("Fehler beim Setzen von BeanShell var " + mapEntry);
                }
            }
        }
        
        try
        {
            i.eval(this.beanShellScript);
            String transition = (String)i.get("transition");
            return transition;
        }
        catch (EvalError e)
        {
            logger.error("Fehler beim Ausfuehren des BeanShell-Scriptes " + this.beanShellScript);
            throw new RuntimeException("Fehler beim Ausfuehren des BeanShell-Scriptes " + this.beanShellScript);
        }
    }

}