sitemesh + ww1 + velocity

"Jan Berkel" <[email protected]> Wed, 31 Mar 2004 02:09:12 +0200 (CEST)

Newsgroups	gmane.comp.web.sitemesh.general
Message-ID	<[email protected]>

Hi,

I adapted the VelocityDecoratorServlet from CVS to work with Webwork1. It
will use the velocity config from webwork (basically a cut and paste
from VelocityHelper).

I wanted to be able to access the action from the decorator page, for
error messages display etc.

The problem is that at decorating-time the action is no longer on the
value stack, and the VelocityDecoratorServlet doesn't use webwork's own
context. A workaround was to grab the action from the attribute
"webwork.valuestack.head" and to setup a valuestack containing just this
action. The static class WebWorkVelocityContext is also a cut'n'paste
from VelocityHelper (it has package access there, unfortunately).

Is there are better way ? Or shouldn't the decorator page have access to
framework internals ?

        Jan

WebWorkVelocityDecoratorServlet.java (text/x-java, 2.7 KB)

import com.opensymphony.module.sitemesh.velocity.VelocityDecoratorServlet;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.context.Context;
import webwork.config.Configuration;
import webwork.dispatcher.ServletDispatcher;
import webwork.util.ServletValueStack;

import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Properties;

/**
 * WebWork specific decorator for sitemesh.
 */
public class WebWorkVelocityDecoratorServlet extends VelocityDecoratorServlet {

    protected Properties loadConfiguration(ServletConfig config) throws IOException, FileNotFoundException {
        // WebWork configuration provides main config
        final Properties conf = new Properties() {
            public Object get(Object key) {
                return Configuration.get(key.toString());
            }

            public String getProperty(String key) {
                return Configuration.getString(key.toString());
            }

            public Enumeration keys() {
                final Iterator list = Configuration.list();
                return new Enumeration() {
                    public Object nextElement() {
                        return list.next();
                    }

                    public boolean hasMoreElements() {
                        return list.hasNext();
                    }
                };
            }
        };

        return conf;
    }

    protected Context createContext(HttpServletRequest request, HttpServletResponse response) {
        Context ctxt;
        ServletValueStack vs = new ServletValueStack();
        // push last action on stack on new vs
        vs.pushValue(request.getAttribute(ServletDispatcher.STACK_HEAD));
        ctxt = new WebWorkVelocityContext(vs);

        ctxt.put(REQUEST,  request);
        ctxt.put(RESPONSE, response);
        return ctxt;
    }

    /**
     * WebWork specific Velocity context implementation.
     */
    public static class WebWorkVelocityContext extends VelocityContext {
        ServletValueStack stack;

        WebWorkVelocityContext(ServletValueStack aStack) {
            stack = aStack;
        }

        public boolean internalContainsKey(java.lang.Object key) {
            boolean contains = super.internalContainsKey(key);
            return contains ? true : stack.test(key.toString());
        }

        public Object internalGet(String key) {
            return super.internalContainsKey(key) ? super.internalGet(key) : stack.findValue(key);
        }
    }
}