Hi,
I've encountered an indexed property problem (common in Struts) when
navigating from one page to another if checkboxes are checked in the
page that I'm navigating from:
[6/28/05 12:51:01:354 EDT] 44bb6cd5 WebGroup E SRVE0026E: [Servlet
Error]-[BeanUtils.populate]: java.lang.NullPointerException
at
org.apache.commons.beanutils.PropertyUtils.getIndexedProperty(PropertyUt
ils.java:497)
at
org.apache.commons.beanutils.PropertyUtils.getIndexedProperty(PropertyUt
ils.java:410)
at
org.apache.commons.beanutils.PropertyUtils.getNestedProperty(PropertyUti
ls.java(Compiled Code))
at
org.apache.commons.beanutils.PropertyUtils.getProperty(PropertyUtils.jav
a(Inlined Compiled Code))
at
org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java(Compil
ed Code))
at
org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java(Compiled
Code))
at
org.apache.struts.util.RequestUtils.populate(RequestUtils.java(Compiled
Code))
at
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcess
or.java:779)
at
com.ford.focit.web.UTF8RequestProcessor.processPopulate(UTF8RequestProce
ssor.java:38)
at
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:
246)
at
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1292)
at
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:510)
I think that I've found the cause of the problem but need some help with
the solution.
I've identified a workaround but I'd like to apply the ideal solution if
one exists.
Here is a description of the problem.
- the page that I'm navigating from has the following code in its action
form:
public class ProgramBaseForm extends IsisBaseForm {
/**
* The program map.
*/
SortedMap programMap = new TreeMap();
/**
* Returns the program list.
* @return ProgramPTO[]
*/
public ProgramVO[] getProgramList() {
ArrayList programList = new ArrayList();
programList.addAll(programMap.values());
return ((ProgramVO[]) programList.toArray(new ProgramVO[0]));
}
/**
* Sets the program list.
* @param programList The program list
*/
public void setProgramList(ProgramVO[] programList) {
SortedMap map = new TreeMap();
for (int i=0; i<programList.length; i++) {
ProgramVO programVO = (ProgramVO) programList[i];
map.put(new Integer(i), programVO);
}
this.programMap = map;
}
/**
* Returns the program list.
* @param index The index
* @return ProgramPTO
*/
public ProgramVO getProgramList(int index) {
Integer key = new Integer(index);
ProgramVO programVO = (ProgramVO) this.programMap.get(key);
if (programVO == null) {
programVO = new ProgramVO();
this.programMap.put(key, programVO);
}
return programVO;
}
/**
* Sets the program list.
* @param index The index
* @param program The program
*/
public void setProgramList(int index, ProgramVO programVO) {
Integer key = new Integer(index);
if (index < getProgramList().length) {
this.programMap.put(key, programVO);
}
}
- the page that I'm navigating to has the following code in its action
form:
public class IncentiveGridBaseForm extends IsisBaseForm {
private List programList;
/**
* Returns the programList.
* @return List
*/
public List getProgramList() {
return programList;
}
/**
* Sets the programList.
* @param programList
*/
public void setProgramList(List programList) {
this.programList = programList;
}
As you can see, the forms implement programList differently which is the
cause of the problem. In order for indexed properties to work, the code
in the first form is appropriate. The exception occurs because the
second form uses List which does not work for indexed properties. The
issue is that I did develop the first form but not the second and I
believe that neither form should need to be changed to solve this
problem (my workaround is to rename programList in either the first or
second form, but this is not ideal).
Has anyone encountered this problem before and if so, how did you solve
it?
Thanks in advance for your help.
Regards,
Christina Siena
