Speed up a slow JSF XHTML editing experience in Eclipse or IBM RAD/RSA.

Speed up a slow JSF XHTML editing experience in Eclipse or IBM RAD/RSA.

If you find yourself doing some JSF (Java Server Faces) development within either Eclipse, IBM’s RAD (Rapid Application Developer) or IBM RSA (Rational Software Architect) IDEs you may find that the JSF editor can run slowly with some lag. This seems particularly a problem on RAM starved machines and/or older versions of the Eclipse/RAD IDEs. The problem (which can be intermittent) is very frustrating and can result in whole seconds going by after typing before your changes appear in the editor. It seems that the JSF code validator is taking too long to re-validate the edited JSF code file. At one point this got so bad for our team many would revert to making JSF changes in a text editor and then copy/paste the final code into the IDE.

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Thankfully there is a workaround and in order that I don’t forget if I hit this problem again I’m posting it here. The workaround (although sadly not a fix) is to use a different “editor” within the same IDE. If you right click the JSF file you want to edit and use the pop-up menu to choose to open it with the XML Editor instead of the XHTML Editor then you will find a much faster experience. Whilst this does remove some of the JSF/XHTML specific validations it provides support for tags etc and will perform faster.

Should you wish to always use the XML Editor to edit XHTML files you can make this global change via the preferences. Go to General > Editors > File Associations > File Types list > select XHTML extension > click Add > Add XML Editor. Then in the associated editors list select the XML Editor and click the ‘Default’ button – thus making XML Editor the default for all XHTML files. Of course once this is done you can still click on individual XHTML files and right click to open in the original XHTML editor should you want to temporarily switch back for an individual file.

Hopefully this will prevent you pulling your hair out in frustration when editing XHTML files.

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Setting HTTP Headers in Java Server Faces (JSF)

Setting HTTP Headers in Java Server Faces (JSF)

In my last post  I discussed using HTTP headers to control browser caching of sensitive data. The post can be found here. The examples provided in that post were all ASP.Net and so I thought I’d cover how to explicitly set your HTTP Response headers when you are using the Java JSF framework.

Adding Headers via Code

You can set HTTP response headers directly in your code via the HTTPServletResponse object, as below:

import javax.servlet.http.HttpServletResponse;

ExternalContext context = FacesContext.getCurrentInstance().getExternalContext();
HttpServletResponse response =  (HttpServletResponse)context.getResponse();
response.setHeader("TestHeader", "hello");

This results in the addition of this header in the HTTP Response: TestHeader: hello.

Adding Headers in your XHTML Markup

Alternatively you can set it directly on each XHTML page via an event tag, as shown in the example below:

<f:event type="preRenderView" listener="#{facesContext.externalContext.response.setHeader('TestHeader', 'hello')}" />
  <h:form>
    <h:panelGrid columns="2">
      <h:outputText value="Name"></h:outputText>
      <h:inputText value="#{LoginBean.name}"></h:inputText>
      <h:outputText value="Password"></h:outputText>
      <h:inputSecret value="#{LoginBean.password}"></h:inputSecret>
    </h:panelGrid>
    <h:commandButton action="welcome" value="Submit" />
</h:form>

This again results in the addition of this header in the HTTP Response: TestHeader: hello.

Adding Headers via a custom Web Filter

In order to implement a solution across your whole web application and for the ability to set headers for different resource types (not just facelets), a web filter may be what you need. Filters intercept your requests and responses to dynamically transform them or use the information contained in them. A good guide to Filters is this official Oracle one – The Essentials of Filters, or check this one out – Servlet Filter to Set Response Headers .

Here is the source code for a simple filter that sets a custom header and can be used to explicitly set HTTP response headers as required:

package Filters; 
import java.io.IOException; 
import javax.servlet.Filter; 
import javax.servlet.FilterChain; 
import javax.servlet.FilterConfig; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRequest; 
import javax.servlet.ServletResponse; 
import javax.servlet.http.HttpServletResponse;

public class HeaderFilter implements Filter 
{ 
    public void init(FilterConfig fc) throws ServletException {} 

    public void doFilter(ServletRequest req, ServletResponse res, 
            FilterChain fc) throws IOException, ServletException 
    { 
        HttpServletResponse response = (HttpServletResponse) res; 
        response.setHeader("TestHeader", "hello"); 
        fc.doFilter(req, res); 
    } 

    public void destroy() {} 
}

Once you’ve coded your filter you need to update your Web.xml file to tell the framework that you want to use this filter. Do this by adding a filter element containing the name and class details. You also need to set a filter-mapping element to map the filter with the request for resources. In the below example which configures the Filter above I have mapped “/*”  meaning all requests will go through the filter but you can configure this to only impact certain resources or file types.

<filter>
  <filter-name>MapThisCustomHeaderFilter</filter-name>
  <filter-class>Filters.HeaderFilter</filter-class>
  <init-param>
    <param-name>value</param-name>
    <param-value>test</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>MapThisCustomHeaderFilter</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>

Once configured via the web.xml file the custom header sets this header on all respones: TestHeader : hello.