/**
 *
 */
package com.acme.result;

import java.io.Writer;

import org.apache.log4j.Logger;

import org.apache..ServletActionContext;
import com.opensymphony.xwork.ActionInvocation;
import com.opensymphony.xwork.Result;
import com.sun.syndication.feed.synd.SyndFeed;
import com.sun.syndication.io.SyndFeedOutput;

/**
 * A simple Result to output a Rome SyndFeed object into a newsfeed.
 * @author Philip Luppens
 *
 */
public class RomeResult implements Result {

	private String feedName;

	private String feedType;

	private final static Logger logger = Logger.getLogger(RomeResult.class);

	/*
	 * (non-Javadoc)
	 *
	 * @see com.opensymphony.xwork.Result#execute(com.opensymphony.xwork.ActionInvocation)
	 */
	public void execute(ActionInvocation ai) throws Exception {
		if (feedName == null) {
			// ack, we need this to find the feed on the stack
			logger
					.error("Required parameter 'feedName' not found. "
							+ "Make sure you have the param tag set and "
							+ "the static-parameters interceptor enabled in your interceptor stack.");
			// no point in continuing ..
			return;
		}

		// don't forget to set the content to the correct mimetype
		ServletActionContext.getResponse().setContentType("text/xml");
		// get the feed from the stack that can be found by the feedName
		SyndFeed feed = (SyndFeed) ai.getStack().findValue(feedName);

		if (logger.isDebugEnabled()) {
			logger.debug("Found object on stack with name '" + feedName + "': "
					+ feed);
		}
		if (feed != null) {

			if (feedType != null) {
				// Accepted types are: rss_0.90 - rss_2.0 and atom_0.3
				// There is a bug though in the rss 2.0 generator when it checks
				// for the type attribute in the description element. It's has a
				// big 'FIXME' next to it (v. 0.7beta).
				feed.setFeedType(feedType);
			}
			SyndFeedOutput output = new SyndFeedOutput();
			//we'll need the writer since Rome doesn't support writing to an outputStream yet
			Writer out = null;
			try {
				out = ServletActionContext.getResponse().getWriter();
				output.output(feed, out);
			} catch (Exception e) {
				// Woops, couldn't write the feed ?
				logger.error("Could not write the feed", e);
			} finally {
				//close the output writer (will flush automatically)
				if (out != null) {
					out.close();
				}
			}

		} else {
			// woops .. no object found on the stack with that name ?
			logger.error("Did not find object on stack with name '" + feedName
					+ "'");
		}
	}

	public void setFeedName(String feedName) {
		this.feedName = feedName;
	}

	public void setFeedType(String feedType) {
		this.feedType = feedType;
	}

}

<package name="default" extends="struts-default">
	<result-types>
		<result-type name="feed" class="com.acme.result.RomeResult"/>
	</result-types>
	<interceptors>
..

<action name="feed" class="com.acme.action.CreateFeedAction">
	<result name="success" type="feed">
		<param name="feedName">feed</param>
		<param name="feedType">rss_1.0</param>
	</result>
</action>