[MYFACES-3128] Problems with a custom Resource Resolver

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.0.5
• Fix Version/s: 2.1.0
• Environment: GlassFish 3.0 with Oracle JVM 1.6 and Websphere 7.0.0.13 with IBM JVM 1.6
• Assignee: Unassigned
• Reporter: Juan Fernandez Corugedo
• Created: 06/May/11 13:16
• Updated: 24/May/11 13:47
• Resolved: 09/May/11 08:07

Description

Hi.

I'm working in a project with Myfaces 2.0.5 (or 2.1.0) and I have had a problem with a custom ResourceResolver.

I have coded a ResourceResolver that dynamically builds an XHTML file when the engine asks him to resolve a certain URL.

To achieve this, I have update the web.xml as follows:

<context-param>
<param-name>javax.faces.FACELETS_VIEW_MAPPINGS</param-name>
<param-value>.test;.xhtml</param-value>
</context-param>

<context-param>
<param-name>javax.faces.FACELETS_RESOURCE_RESOLVER</param-name>
<param-value>com.test.view.facelets.CustomResourceResolver</param-value>
</context-param>

My CustomResourceResolver is very simple:

package com.test.view.facelets;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;

import javax.faces.view.facelets.ResourceResolver;

public class CustomResourceResolver extends ResourceResolver {

private ResourceResolver innerResourceResolver;

private String viewSource = ".... xhtml of the test page ....";

public CustomResourceResolver(ResourceResolver resourceResolver)

{ this.innerResourceResolver = resourceResolver; }

@Override
public URL resolveUrl(String path) {
System.out.println("Buscando la URL del recurso: " + path);
URL result = null;

if(path.endsWith(".test")){
try

{ result = getUrlForResourceAsStream(path); }

catch(Exception e)

{ System.out.println("Unexpected error while obtaining the URL from resource " + path); e.printStackTrace(System.out); }

}else

{ result = this.innerResourceResolver.resolveUrl(path); }

return result;
}

private URL getUrlForResourceAsStream(String path) throws MalformedURLException {
URLStreamHandler handler = new URLStreamHandler() {
protected URLConnection openConnection(URL u) throws IOException {
final String file = u.getFile();
return new URLConnection(u) {
public void connect() throws IOException {
}

public InputStream getInputStream() throws IOException {
System.out.println("Opening internal url to " + file);

try

{ System.out.println("Generando el InputStream de la pagina:\n" + viewSource); return new ByteArrayInputStream(viewSource.getBytes("UTF-8")); }

catch (Exception e)

{ e.printStackTrace(); throw new RuntimeException("Unexpected error while obtaining the view", e); }

}
};
}
};
return new URL("internal", null, 0, path, handler);
}
}

As you can see, the code is very simple. When the suffix matches the pattern ".test", the Resolver creates a mock URL with a backing ByteArrayInputStream. If the suffix does not matches the pattern, the normal ResourceResolver is invoked.

With this configuration and code, when I request the URL: http://xxxxxx:yyyy/zzzzz/anything.test the application fails with error:

The problem is this:

java.lang.NullPointerException
at java.lang.StringBuilder.<init>(StringBuilder.java:92)
at org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.getRenderedViewId(FaceletViewDeclarationLanguage.java:1630)
at org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.buildView(FaceletViewDeclarationLanguage.java:279)
....

The executes the viewHandler.createView("xxxx.test") method. It internally calls the getViewHandlerSupport().calculateViewId(context, viewId); method to obtain the viewId, and this method calls DefaultViewHandlerSupport.checkResourceExists(FacesContext context, String viewId), that checks the physical file of this resource, but there are not any file for this resource!!!! so it return false, and the viewId of the resulting ViewRoot is assigned to null.

This causes a NullPointerException later, when the code executes the ViewDeclarationLanguage.buildView(FacesContext context, ViewRoot viewRoot).

If I change the Myfaces implementation with Mojarra 2.0.4, it works perfectly, so I think that the problem is in the implementation.

I can't extend any class of interface of Myfaces, because my application must not be coupled to a specific implementation.

I have attached two web projects, one with Myfaces configuration, that fails, and the same project with Mojarra configuration, that works