error on back to previous page (a page saved in state)

[mike mike]

Hello All, I have 2 pages, page A and B. Page A is a page that allow user to
search, the result will be shown in a table with the link to the page B.
Page B will have a "Back" button to navigate back the previous page which is
page A (with the details that was entered previously). But I've encountered
the problems on restoring the *Table* object from the previous page. If I
saved the whole page object to the state, shouldnt it saved all the
instances inside the object which wouldnt cause the problem of
NullPointerException on getting the TableModelSource? What did i do it
wrong?

Page A will be saved into the "*tapestry.state.ApplicationObjects*" with the
scope of "*session*".

Im not sure if the design of mine that navigate between pages is correct,
anyone can help?

Thanks in advanced.

Mike,


  java.lang.NullPointerException  Stack Trace:

   -
   
org.apache.tapestry.contrib.table.components.AbstractTableViewComponent.getTableModelSource
   (AbstractTableViewComponent.java:35)
   -
   
org.apache.tapestry.contrib.table.components.TableColumns.getTableColumnIterator
   (TableColumns.java:91)
   - sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   - sun.reflect.NativeMethodAccessorImpl.invoke(
   NativeMethodAccessorImpl.java:39)
   - sun.reflect.DelegatingMethodAccessorImpl.invoke(
   DelegatingMethodAccessorImpl.java:25)
   - java.lang.reflect.Method.invoke(Method.java:585)

*Page A:*
@InjectState("pageA")
 public abstract void setPage(BasePage page);

public void toPageB()
{
setPage(this);
}

*Page B:*
@InjectState("pageA")
public abstract BasePage getPage();

public void toPageA(IRequestCycle cycle)
{
PageA pagea = (PageA) getPage();
cycle.activate(pagea);
}