beanshellvalidator.java

一个很好实用的工作流OSWORKFLOW开发例子.有着非常优秀的灵活性.

/*
 * Copyright (c) 2002-2003 by OpenSymphony
 * All rights reserved.
 */
package com.opensymphony.workflow.util.beanshell;

import bsh.Interpreter;
import bsh.TargetError;

import com.opensymphony.module.propertyset.PropertySet;

import com.opensymphony.workflow.*;
import com.opensymphony.workflow.spi.WorkflowEntry;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.util.Map;


/**
 * Beanshell inline script validator.
 * The input is determined to be invalid of the script throws a  {@link InvalidInputException}.
 */
public class BeanShellValidator implements Validator {
    //~ Static fields/initializers /////////////////////////////////////////////

    private static final Log log = LogFactory.getLog(BeanShellValidator.class);

    //~ Methods ////////////////////////////////////////////////////////////////

    public void validate(Map transientVars, Map args, PropertySet ps) throws WorkflowException {
        Interpreter i = new Interpreter();
        ClassLoader loader = Thread.currentThread().getContextClassLoader();

        try {
            String contents = (String) args.get(AbstractWorkflow.BSH_SCRIPT);

            WorkflowContext context = (WorkflowContext) transientVars.get("context");
            WorkflowEntry entry = (WorkflowEntry) transientVars.get("entry");

            if (loader != null) {
                i.setClassLoader(loader);
            }

            i.set("entry", entry);
            i.set("context", context);
            i.set("transientVars", transientVars);
            i.set("propertySet", ps);

            Object o = i.eval(contents);

            if (o != null) {
                throw new InvalidInputException(o);
            }
        } catch (TargetError e) {
            if (e.getTarget() instanceof WorkflowException) {
                throw (WorkflowException) e.getTarget();
            } else {
                throw new WorkflowException("Unexpected exception in beanshell validator script:" + e.getMessage(), e);
            }
        } catch (Exception e) {
            String message = "Error executing beanshell validator";
            throw new WorkflowException(message, e);
        } finally {
            if (loader != null) {
                i.setClassLoader(null);
            }
        }
    }
}