ResponsePhaseListener.java

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package renderkits.renderkit.svg;

import javax.faces.context.FacesContext;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;
import javax.servlet.http.HttpServletResponse;

import java.util.Map;

/**
 * This <code>PhaseListener</code> executes after Invoke Applications
 * Phase of the request processing lifecycle.  It detects the presence
 * of an <code>XMLHttpRequest</code> and:
 * <ul><li>grabs the request URI from the request (this will be the
 * URI of the new uocoming view) and adds it to the response;</li>
 * </ul>
 */
public class ResponsePhaseListener implements PhaseListener {

    private static final String XML_HTTP = "XML-HTTP";
    private static final String VIEW_URI = "VIEW-URI";

    public ResponsePhaseListener() {
    }

    public void afterPhase(PhaseEvent event) {
        // Disregard requests that are not XMLHttpRequest(s) 
        Map<String, String> requestHeaderMap =
              event.getFacesContext().getExternalContext().
                    getRequestHeaderMap();
        if (requestHeaderMap.get(XML_HTTP) == null) {
            return;
        }
        // If we're dealing with an XMLHttpRequest...
        // Get the URI and stuff it in the response header.
        FacesContext context = event.getFacesContext();
        String viewId = context.getViewRoot().getViewId();
        String actionURL = context.getApplication().getViewHandler()
              .getActionURL(context, viewId);
        HttpServletResponse response =
              (HttpServletResponse) context.getExternalContext().getResponse();
        response.setHeader("Cache-Control", "no-cache");
        response.setHeader(VIEW_URI, actionURL);
    }

    public void beforePhase(PhaseEvent event) {
    }

    public PhaseId getPhaseId() {
        return PhaseId.INVOKE_APPLICATION;
    }
}