DO NOT REPLY [Bug 23465] New: - "indexed" form data cannot be parsed by a struts DynaActionForm bean

[bu...@apache.org]

DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG 
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://nagoya.apache.org/bugzilla/show_bug.cgi?id=23465>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND 
INSERTED IN THE BUG DATABASE.

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=23465

"indexed" form data cannot be parsed by a struts DynaActionForm bean

           Summary: "indexed" form data cannot be parsed by a struts
                    DynaActionForm bean
           Product: Struts
           Version: 1.1 Beta 3
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: Normal
          Priority: Other
         Component: Custom Tags
        AssignedTo: struts-dev@jakarta.apache.org
        ReportedBy: minfrin@sharp.fm


If an attempt is made to publish iterative data from a DynaFormBean in a
webform, for example N line items on an invoice, this data cannot be read back
again into the DynaFormBean for processing (validation / whatever).

If a form bean is defined like so:

<form-bean
  name="invoiceForm"
  type="org.apache.struts.action.DynaActionForm">
  <form-property
    name="description"
    type="java.lang.String[]" />
  <form-property
    name="quantity"
    type="java.lang.String[]" />
  <form-property
    name="price"
    type="java.lang.String[]" />
</form-bean>

An Action pre-populates the above data with a number of line items, the number
of which is decided by the Action.

Problem A:
----------

If the struts tags are rendered as follows:

<logic:iterate indexId="index" id="description" name="invoiceForm"
property="description" />
<html:text indexed="true" property="description" />
<html:text indexed="true" property="quantity" />
<html:text indexed="true" property="price" />
</logic:iterate>

the values generated for the forms are as follows:

[L.java.lang.String;@1c7e176
[L.java.lang.String;@1c7e176
[L.java.lang.String;@1c7e176

the names generated for the text fields are as follows:

org.apache.struts.taglib.html.BEAN[0].description
org.apache.struts.taglib.html.BEAN[0].quantity
org.apache.struts.taglib.html.BEAN[0].price

With this method, the values are broken, and the form displayed is corrupt.

Problem B:
----------

If the struts tags are rendered as follows:

<logic:iterate indexId="index" id="description" name="invoiceForm"
property="description" />
<html:text indexed="true" property="<%=\"description[\" + index + \"]\"%>" />
<html:text indexed="true" property="<%=\"quantity[\" + index + \"]\"%>" />
<html:text indexed="true" property="<%=\"price[\" + index + \"]\"%>" />
</logic:iterate>

the values generated for the forms are the correct values as prepopulated by
the Action.

the names generated for the text fields are as follows:

org.apache.struts.taglib.html.BEAN[0].description[0]
org.apache.struts.taglib.html.BEAN[0].quantity[0]
org.apache.struts.taglib.html.BEAN[0].price[0]

When the above names are submitted in the form, and struts attempts to
populate the DynaActionForm bean from the values on the page, the above
names are not recognised as valid entries in the bean, and are so ignored.

Problem C:
----------

If an additional struts html submit tag is added to the mix, say to delete
a line item from the invoice, like so:

<logic:iterate indexId="index" id="description" name="invoiceForm"
property="description" />
<html:submit indexed="true" property="<%=\"delete[\" + index + \"]\"%>"
value="Delete" />
</logic:iterate>

The name is rendered as:

delete[0]

If an attempt is made to submit this form using this submit button, struts
attempts to populate the DynaActionForm bean. This time round, struts
recognises the "delete" part as an entry in the DynaActionForm bean, and
tries to set index "0" on that particular entry. However - struts has made
no attempt to create a suitable String[] array inside the DynaActionForm bean,
so the attempt bombs out with an ArrayIndexOutOfBoundsException.

Conclusion:
-----------

The most elegant way of expressing the config for the above is described
in problem A above. This way there is no need for ugly scriplets to embed
the index, it is all handled by the indexed="true" parameter.

The fix for this seems to be:

- Make the indexed="true" mechanism understand how to deal with String[]'s.
- Make the name of the form come out as "description", OR make the name come out
as "description[0]", but then struts must be taught how to populate a 
String[] correctly without throwing the ArrayLindexOutOfBoundsException. Struts
already knows how to do with normal multi-valued parameters in a form.

---------------------------------------------------------------------
To unsubscribe, e-mail: struts-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-dev-help@jakarta.apache.org