workflowserializer.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.loader;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;

import java.io.ByteArrayOutputStream;
import java.io.OutputStreamWriter;


/**
 * DOCUMENT ME!
 *
 * @author $author$
 * @version $Revision: 1.2 $
 */
public class WorkflowSerializer {
    //~ Instance fields ////////////////////////////////////////////////////////

    private VelocityEngine engine;

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

    public byte[] generateWorkflowXML(WorkflowDescriptor wf) throws Exception {
        initVelocity();

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        OutputStreamWriter writer = new OutputStreamWriter(baos);
        Template template = engine.getTemplate("workflowtemplate.vm");
        VelocityContext ctx = new VelocityContext();
        ctx.put("workflow", wf);
        template.merge(ctx, writer);
        writer.flush();
        baos.flush();

        return baos.toByteArray();
    }

    protected void initVelocity() throws Exception {
        if (engine == null) {
            engine = new VelocityEngine();
            engine.setProperty("resource.loader", "class");
            engine.setProperty("class.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
            engine.init();
        }
    }
}