Calling a servlet from a backing bean

[Lance Cash]

I've been poking around all over the place looking for how one can invoke a servlet from within a backing bean and have come up empty. The most promising code I found was:

        FacesContext fc = FacesContext.getCurrentInstance();
        try {
            fc.getExternalContext().dispatch(url);
        } catch (Exception e) {
            this.logger.error("Failed to generate Chain of Custody report", e);
            FacesMessage message = new FacesMessage();
            message.setDetail("Failed to generate Chain of Custody report");
            message.setSeverity(FacesMessage.SEVERITY_ERROR);
            FacesContext.getCurrentInstance().addMessage("failure", message);
        } finally {
            fc.responseComplete();
        }

The problem is...it doesn't work! I don't know if it is an icefaces issue or what, but I get the following error:

java.io.IOException: Cannot dispatch on XMLHTTP request.

I'm hoping someone out there will have other ideas, and please...no suggestions on how to better design this thing. It's gotta stay a servlet! This isn't the only place this thing gets used. I am open, however to other suggestions on how to call the servlet. Originally, it was being invoked via an outputLink, but now it needs to perform some action as well. I realize that I could create a hidden input button and invoke it with some javascript, but that just seems awfully hokie to me. I would like to present my boss with a more elegant solution than that.

Thanks in advance, everyone. Lance.

[Cameron Wallace McKenzie]

What is the role of the Servlet in this case? Does it perform business logic exclusively, or does it generate markup for display?

[Lance Cash]

It is generating a pdf report of system activity.

[Lance Cash]

Alright, well...I figured out how to call the servlet from the backing bean, but it ended up not helping me out. This particular servlet needs to be invoked from the right context in order to execute properly so that it can grab stuff like the user state from the session. When calling it from a bean as I did, that stuff isn't instantiated. But for anyone that may be interested in how to do this in the future, here you go:

        try {
            URL url = new URL("http://youserver/chainOfCustody?mode=video");
            URLConnection conn = url.openConnection();

            BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;

            while ((line = rd.readLine()) != null) {
                System.out.println("Response: " + line);
            }
            rd.close();
        } catch (Exception e) {
            this.logger.error("Failed to generate Chain of Custody report", e);
            FacesMessage message = new FacesMessage();
            message.setDetail("Failed to generate Chain of Custody report");
            message.setSeverity(FacesMessage.SEVERITY_ERROR);
            FacesContext.getCurrentInstance().addMessage("failure", message);
        }

I ended up having to call on javascript to the rescue after all via a hidden button invoked by the onclick() method of the outputLink tag.

Thanks anyways, guys.