As I've found with my involvement in contributing to
the Bugzilla project, radification/confirmation of
design/implementation details is critical to
acceptance of a submitted patch. Below are the
changes I propose to make this happen. The String -->
Date direction is significanly more involved than
rendering the date as a String. I investigated
performing the conversion in ConvertUtils for both,
but without overloading the Converter.convert
interface to accept a map of conversion parameters
made available to the registered Converter
implementations this is not possible. Further more,
the BeanUtils.populate method signature would also
need to change to accomodate a collection of property
specific conversion parameter name/value pairs to use
this new convert method. Thus what's outlined below
involves changes in the Struts code base only!
String --> Date
1) Add "dateformat" attribute to all html input tags.
This would specify the java.text.SimpleDateFormat
pattern of the string being submitted. Tag would
generate hidden field and a PropertyConversionParam
(new class) instance stored under the user's session
with PropertyConversionParam.getKey() used as the
session attribute and the hidden field name. This
would only be performed by the tag if the bean's
property type was a date AND 'dateformat' attribute
was specified.
Scratchpad of PropertyConversionParam class:
PropertyConversionParam {
public static final String KEY_PREFIX =
"conversion-param";
public static final String DATE_CONVERSION_PATTERN =
"dateConversionPattern";
//simple setter/getter properties
private String beanName;
private String property;
private String paramName;
private String conversionValue;
//calculated namespace key
private String key = null;
public String getKey() {
if (key == null) {
key = KEY_PREFIX +
String.valueOf(beanName.hashCode()) +
String.valueOf(property.hashCode()) +
String.valueOf(paramName.hashCode());
}
return key;
}
}
2) Modify RequestUtils.populate:
* For each property that has a dateformat value
present remove Session PropertyConversionParam
attribute and do not store name/value pair in map
given to BeanUtils.populate method.
* If there is a null attribute value ignore and allow
existing Converters to attempt conversion.
3) Add new DateUtil class to struts util package with
methods:
- java.util.Date toDate(String pattern, String value)
- String toString(String pattern, java.util.Date
value)
Realizing the tidyness of centralizing the conversion
behaviour, these methods could simply be added to the
ConvertUtils.
4) Modify RequestProcessor.processPopulate
(processPopulateConversions ?):
* After call to RequestUtils.populate() remove
session attributes that begin with
PropertyConversionParam.KEY_PREFIX
* For each PropertyConversionParam that has a
non-null request parameter conversion value, call
BeanUtils.setProperty(Object, String, Object) after
convert the string date to date a java.util.Date using
DateUtil.toDate.
PropertyConversionParam.getConversionValue() would
provide 'pattern' parameter while request would
provide the 'value' parameter.
* For each string --> date conversion that fails add
a ActionError instance for the property and follow
same redirect logic detailed in processValidate method
(perhaps a method extract refactoring).
Date --> String
1) add "dateformat" attribute to bean:write tag & all
html input tags
2) modify tag to call DateUtil.toString if bean
property is of type Date and "dateformat" attribute is
not null
Please realize this is a first cut and I expect to
incorporate loads of feedback prior to submitting a
patch.
--- Joe Germuska <[EMAIL PROTECTED]> wrote:
> At 11:23 -0700 6/27/03, Jon Wilmoth wrote:
> >I'm reposting as the previous attempt may have
> gotten
> >lost in the new release excitement.
> >
> >I'd like to know what the CURRENT plans are for
> >supporting date datatypes in the framework. This
> >means conversion of strings --> dates for FormBean
> >population and the converse date --> string for
> >rendering FormBean values.
>
> I think submitting a patch would be the most
> effective way to get
> this put into plans. But note that the
> string-to-object conversion
> is generally handled in Commons BeanUtils, not
> directly in Struts.
> The Struts "problem" to solve is where to specify
> the date format
> conversion, and unless you want to support only one
> date format for a
> whole application, how to pass date formats along to
> the form
> population process at the right time.
>
> How do you propose to handle the variety of possible
> date formats?
> Between the fact that that's a mildly complicated
> question and the
> fact that at least some Struts developers think that
> you should just
> use String types for all text fields in your forms,
> I suspect that's
> why you haven't seen any "official" support.
>
> But if you submit a patch or at least start a
> discussion of the
> implementation issues, I'm sure you'll get opinions.
> There are lots
> of those around here ;-)
>
> Joe
>
> --
> --
> Joe Germuska
> [EMAIL PROTECTED]
> http://blog.germuska.com
> "If nature worked that way, the universe would crash
> all the time."
> --Jaron Lanier
>
>
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