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Posted to cactus-user@jakarta.apache.org by Mamadou Cisse <ma...@alatto.com> on 2004/09/29 16:54:43 UTC
java.lang.NullPointerException and RequestDispatcherWrapper.forward_aroundBody0
After spending almost long fruitless hours searching the net for clues,
I couldn't find any better place to ask than this list.
I'm using cactus 1.6 to unit/integration test J2EE components, servlets
in this particular case. My environment is Jetty/Cactus/Eclipse 3.0.
My test case extends the Cactus ServletTestCase class.
In the setUp method i create an instance of my servlet to be tested.
........
myServlet = new MyServlet();
........
In the beginMyTest(WebRequest request) method I set the URL as:
.......
request.setURL(
"myserver:port",
"/contextpath",
"/some/path/someCommand.pp", null, null);
.......
Now in the testMyTest() method I call myServlet's doPost method. like:
.......
servlet.init(config);
myServlet.doPost(request, response);
.......
In doPost a command object is created from the parameter request. This
command object does some processing and then returns a String as URL to
the doPost method which in turn tries to forward the call. The
pseudocode looks like:
{pseudocode ---
Command command = CommandFactory.getCommand(request), //1
String urlStr = command.execute(); //2
RequestDispatcher disp = request.getRequestDispatcher(urlStr); //3
disp.forward(request, response); //4
--- pseudocode}
On the line //4 there is a NullPointerException. The reason is that the
originalDispatcher in the RequestDispatcher instance is null.
Any hint would be greatly appreciated.
--------------------------------------------------
java.lang.NullPointerException
at
org.apache.cactus.server.RequestDispatcherWrapper.forward_aroundBody0(RequestDispatcherWrapper.java:71)
at
org.apache.cactus.server.RequestDispatcherWrapper.forward_aroundBody1$advice(RequestDispatcherWrapper.java:117)
at
org.apache.cactus.server.RequestDispatcherWrapper.forward(RequestDispatcherWrapper.java)
at com.mycompany.mypackage.MyServlet.doPost(MyServlet.java:110)
at
com.mycompany.mypackage.test.MyIntegrationTestCase.testMyTest(MyIntegrationTestCase.java:58)
---------------------------------------------------
--
Regards,
Mamadou
Re: java.lang.NullPointerException and
RequestDispatcherWrapper.forward_aroundBody0
Posted by Kazuhito SUGURI <su...@lab.ntt.co.jp>.
Hi,
In article <41...@alatto.com>,
Thu, 30 Sep 2004 09:50:43 +0100,
Mamadou Cisse <ma...@alatto.com> wrote:
mamadou> I went through the code in the debugger. The thing is that the returned
mamadou> instance of the RequestDispatcher is NON-NULL, but this instance has an
mamadou> instance variable called originalDispatcher which is NULL and I believe
mamadou> this to be the cause of the problem.
mamadou> Before instanciating a test suite, I set the cactus.contextURL to
mamadou> http://localhost:aport/mycontext using a call to System.setProperty:
mamadou> System.setProperty("cactus.contextURL",
mamadou> "http://localhost:aport/mycontext");
mamadou> So the question is why originalDispatcher in the returned
mamadou> RequestDispatcher is set to null when a Cactus instanciated
mamadou> HttpServletRequestWrapper is passed to a servlet's doPost method, which
mamadou> in turn calls getRequestDispatcher on the HttpRequestDispatcherWrapper
mamadou> instance?
Thank you. I believe I understand your problem better.
Following is the getRequestDispatcher method of the AbstractHttpServletRequestWrapper:
public RequestDispatcher getRequestDispatcher(String thePath)
{
if (thePath == null)
{
return null;
}
RequestDispatcher dispatcher = null;
String fullPath;
if (thePath.startsWith("/"))
{
fullPath = thePath;
}
else
{
String pI = getPathInfo();
if (pI == null)
{
fullPath = catPath(getServletPath(), thePath);
}
else
{
fullPath = catPath(getServletPath() + pI, thePath);
}
if (fullPath == null)
{
return null;
}
}
LOGGER.debug("Computed full path : [" + fullPath + "]");
dispatcher = new RequestDispatcherWrapper(
this.request.getRequestDispatcher(fullPath));
return dispatcher;
}
Your case can be occured if
this.request.getRequestDispatcher(fullPath)
returns null because null-check for the originalDispatcher is not taken
in the constructor of the RequestDispatcherWrapper.
Here, this.request should be a HttpServletRequest instance
given from your container.
For fullPath value, please follow the logic of the code above.
Is the fullPath value computed from your command.execute() result,
which is given as the argument thePath, valid for your container?
You can also logging the real fullPath value.
Regards,
----
Kazuhito SUGURI
mailto:suguri.kazuhito@lab.ntt.co.jp
Re: java.lang.NullPointerException and RequestDispatcherWrapper.forward_aroundBody0
Posted by Mamadou Cisse <ma...@alatto.com>.
Hi Kazuhito and All the others.
I went through the code in the debugger. The thing is that the returned
instance of the RequestDispatcher is NON-NULL, but this instance has an
instance variable called originalDispatcher which is NULL and I believe
this to be the cause of the problem.
Before instanciating a test suite, I set the cactus.contextURL to
http://localhost:aport/mycontext using a call to System.setProperty:
System.setProperty("cactus.contextURL",
"http://localhost:aport/mycontext");
So the question is why originalDispatcher in the returned
RequestDispatcher is set to null when a Cactus instanciated
HttpServletRequestWrapper is passed to a servlet's doPost method, which
in turn calls getRequestDispatcher on the HttpRequestDispatcherWrapper
instance?
Regards,
Mamadou.
>Hi,
>
>In article <41...@alatto.com>,
>Wed, 29 Sep 2004 15:54:43 +0100,
>Mamadou Cisse <ma...@alatto.com> wrote:
>mamadou> In doPost a command object is created from the parameter request. This
>mamadou> command object does some processing and then returns a String as URL to
>mamadou> the doPost method which in turn tries to forward the call. The
>mamadou> pseudocode looks like:
>mamadou> {pseudocode ---
>mamadou> Command command = CommandFactory.getCommand(request), //1
>mamadou> String urlStr = command.execute(); //2
>mamadou> RequestDispatcher disp = request.getRequestDispatcher(urlStr); //3
>mamadou> disp.forward(request, response); //4
>mamadou> --- pseudocode}
>mamadou> On the line //4 there is a NullPointerException. The reason is that the
>mamadou> originalDispatcher in the RequestDispatcher instance is null.
>
>ServletRequest#getRequestDispatcher(String) returns null
>if the servlet container cannot return a RequestDispatcher.
>So, I think, the point is that the urlStr value returned from command.execute()
>is valid or not.
>
>You might separate the test into some parts like:
> public void testCommand {
> Command command = CommandFactory.getCommand(request);
> assertEquals("expectedUrl", command.execute());
> }
> public void testDispatch {
> assertNotNull(request.getRequestDispatcher("expectedUrl"));
> }
>
>I guess testCommand() fails and/or your expectedUrl is not valid
>for your container.
>
>Hope this helps,
>----
>Kazuhito SUGURI
>mailto:suguri.kazuhito@lab.ntt.co.jp
>
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>
>
>
--
Regards,
Mamadou Cisse
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alatto Technologies
www.alatto.com
t: + 353 1 209 0785
f: + 353 1 209 0707
email: mamadou.cisse@alatto.com
Re: java.lang.NullPointerException and
RequestDispatcherWrapper.forward_aroundBody0
Posted by Kazuhito SUGURI <su...@lab.ntt.co.jp>.
Hi,
In article <41...@alatto.com>,
Wed, 29 Sep 2004 15:54:43 +0100,
Mamadou Cisse <ma...@alatto.com> wrote:
mamadou> In doPost a command object is created from the parameter request. This
mamadou> command object does some processing and then returns a String as URL to
mamadou> the doPost method which in turn tries to forward the call. The
mamadou> pseudocode looks like:
mamadou> {pseudocode ---
mamadou> Command command = CommandFactory.getCommand(request), //1
mamadou> String urlStr = command.execute(); //2
mamadou> RequestDispatcher disp = request.getRequestDispatcher(urlStr); //3
mamadou> disp.forward(request, response); //4
mamadou> --- pseudocode}
mamadou> On the line //4 there is a NullPointerException. The reason is that the
mamadou> originalDispatcher in the RequestDispatcher instance is null.
ServletRequest#getRequestDispatcher(String) returns null
if the servlet container cannot return a RequestDispatcher.
So, I think, the point is that the urlStr value returned from command.execute()
is valid or not.
You might separate the test into some parts like:
public void testCommand {
Command command = CommandFactory.getCommand(request);
assertEquals("expectedUrl", command.execute());
}
public void testDispatch {
assertNotNull(request.getRequestDispatcher("expectedUrl"));
}
I guess testCommand() fails and/or your expectedUrl is not valid
for your container.
Hope this helps,
----
Kazuhito SUGURI
mailto:suguri.kazuhito@lab.ntt.co.jp