Oliver Suciu wrote:
> Actually, it seems to work with exactly those three setters
> mentioned in the example -- I can pass a List in one instance,
> and a String in another.
>
> So now I'm wondering whether it's by design or just by accident?...
By accident, see previous discussion. Also try with Tomcat 4.0
to see what happens.
Hans
> Hans Bergsten wrote:
>
>>Oliver Suciu wrote:
>>
>>
>>>OK -- so it's underspecified. That means that the JRun implementation
>>>is just as correct or incorrect as Tomcat's...
>>>
>>No. Tomcat is the Reference Implementation, so when in doubt,
>>trust Tomcat (yeah, yeah. I know there may be bugs in Tomcat
>>as well ;-)
>>
>>Anyway, this was discussed at length in the spec group. What I
>>tell you is the conclusion of how it should work. There may even
>>be a blurb about this in the JSP 1.2 spec somewhere. Sorry, but
>>I don't have the time to look for it right now.
>>
>>You believe what you want, of course. I can only tell you that
>>if you develop tag handlers with multiple setters, they will
>>not work in most containers. I'm just trying to help, not pick
>>a fight ;-)
>>
>>
>>>BTW, there seems to be a simple (JSP- and Tomcat-compliant) way to
>>>make use of overloaded setters -- use request-time expressions:
>>>
>>>modify: <tag setData='string'>
>>>to: <tag setData='<%="string"%>'>
>>>
>>>This bypasses any conversion and correctly invokes the string setter
>>>'public void setData(String dataStr)'.
>>>
>>This only works if the type of the attribute is Object (again,
>>just one setter method). In JSP 1.1, yes this is what you have to
>>do if you want to assign a String value to the attribute. But it's
>>not very "page author friendly", so in JSP 1.2 you can use a literal
>>string instead, as in your first example.
>>
>>Note that Tomcat 4.0 (the RI for JSP 1.2) is buggy in this area.
>>It's been fixed in the source, so it should work in the latest
>>nightly build.
>>
>>Hans
>>
>>
>>>Hans Bergsten wrote:
>>>
>>>
>>>>Oliver Suciu wrote:
>>>>
>>>>
>>>>
>>>>>You're saying that the spec doesn't say anything about this;
>>>>>how comes you then say that the behavior of Tomcat is the
>>>>>correct one?...
>>>>>
>>>>>
>>>>I'm saying that the bean spec does not explicitly say that
>>>>a property can not have multiple setter methods, nor that it
>>>>can have it. When the spec text is vague, you must look at
>>>>the API and the implementation of the bean classes to find
>>>>out what to expect. Together they imply that a bean property
>>>>can only be associated with one setter method. Look, for
>>>>instance, at the java.beans.PropertyDescriptor class. The
>>>>constructors allow you to set *one* setter method, and the
>>>>getWriteMethod() returns *one* method.
>>>>
>>>>The bean spec group is aware of this and have indicated to me
>>>>that the next rev of the spec will explicitly state this as
>>>>well.
>>>>
>>>>Hans
>>>>
>>>>
>>>>
>>>>>Hans Bergsten wrote:
>>>>>
>>>>>
>>>>>
>>>>>>Oliver Suciu wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>Hi,
>>>>>>>
>>>>>>>Can anybody help clarify how a JSP container should handle
>>>>>>>overloaded setters in a custom tag:
>>>>>>>
>>>>>>>public void setData(List dataList) {
>>>>>>> this.dataList = dataList;
>>>>>>>}
>>>>>>>public void setData(Object dataObj) {
>>>>>>> this.dataObj = dataObj;
>>>>>>>}
>>>>>>>public void setData(String dataStr) {
>>>>>>> this.dataStr = dataStr;
>>>>>>>}
>>>>>>>
>>>>>>>We want to give the JSP author the convenience of passing data
>>>>>>>to a tag using different types, whichever comes in more handy.
>>>>>>>The data would be of the same "logical" kind, that's why, ideally,
>>>>>>>the setters would bear the same name, just like overloaded methods
>>>>>>>in Java.
>>>>>>>
>>>>>>>As an example, JRun 3.1 accepts the code above, whereas Tomcat
>>>>>>>3.2.3 throws a CompileException ("Unable to convert a String
>>>>>>>to java.util.List").
>>>>>>>
>>>>>>>What's the correct behavior?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>Tomcat's behavior is correct. When it comes to attribute setter
>>>>>>methods, a tag handler class is a "bean", so you must go to the
>>>>>>bean spec to see how it deals with property setter methods.
>>>>>>The spec text itself doesn't say anything about multiple setter
>>>>>>methods, but the implementation of the methods that deal with
>>>>>>setter methods only allow one setter method per property. Hence,
>>>>>>multiple setter methods for a tag handler attribute is not
>>>>>>allowed.
>>>>>>
>>>>>>In JSP 1.2 you can get around this by making the type of the
>>>>>>attribute Object, and the figure out which specific type you
>>>>>>got. The reason this only works well with JSP 1.2 is that
>>>>>>JSP 1.1 doesn't accept a string literal as the attribute
>>>>>>value for an attribute of type Object; JSP 1.2 does.
>>>>>>
>>>>>> public void setData(Object data) {
>>>>>> this.data = data;
>>>>>> }
>>>>>>
>>>>>> public int doStartTag() {
>>>>>> if (data instanceof List) {
>>>>>> // Work with it as a List
>>>>>> }
>>>>>> else (data.getClass().isArray()) {
>>>>>> // Work with it as an array
>>>>>> }
>>>>>> else (data instanceof String) {
>>>>>> // Work with as a String
>>>>>> }
>>>>>> else ...
>>>>>> }
>>>>>>
>>>>>>I describe this in more detail in an article that will soon
>>>>>>be published at the O'Reilly site. I'll post the URL here
>>>>>>when it's available.
>>>>>>
>>>>>>Hans
>>>>>>--
>>>>>>Hans Bergsten [EMAIL PROTECTED]
>>>>>>Gefion Software http://www.gefionsoftware.com
>>>>>>Author of JavaServer Pages (O'Reilly), http://TheJSPBook.com
>>>>>>
>>>>>>===========================================================================
>>>>>>To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
>>>>>>For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
>>>>>>Some relevant FAQs on JSP/Servlets can be found at:
>>>>>>
>>>>>>http://java.sun.com/products/jsp/faq.html
>>>>>>http://www.esperanto.org.nz/jsp/jspfaq.html
>>>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
>>>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>>>>>>
>>>>>>
>>>>>>
>>>>>===========================================================================
>>>>>To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
>>>>>For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
>>>>>Some relevant FAQs on JSP/Servlets can be found at:
>>>>>
>>>>>http://java.sun.com/products/jsp/faq.html
>>>>>http://www.esperanto.org.nz/jsp/jspfaq.html
>>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
>>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>>>>>
>>>>>
>>>>>
>>>>>
>>>>--
>>>>Hans Bergsten [EMAIL PROTECTED]
>>>>Gefion Software http://www.gefionsoftware.com
>>>>Author of JavaServer Pages (O'Reilly), http://TheJSPBook.com
>>>>
>>>>===========================================================================
>>>>To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
>>>>For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
>>>>Some relevant FAQs on JSP/Servlets can be found at:
>>>>
>>>>http://java.sun.com/products/jsp/faq.html
>>>>http://www.esperanto.org.nz/jsp/jspfaq.html
>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
>>>>http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>>>>
>>>>
>>>===========================================================================
>>>To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
>>>For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
>>>Some relevant FAQs on JSP/Servlets can be found at:
>>>
>>> http://java.sun.com/products/jsp/faq.html
>>> http://www.esperanto.org.nz/jsp/jspfaq.html
>>> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
>>> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>>>
>>>
>>>
>>--
>>Hans Bergsten [EMAIL PROTECTED]
>>Gefion Software http://www.gefionsoftware.com
>>Author of JavaServer Pages (O'Reilly), http://TheJSPBook.com
>>
>>===========================================================================
>>To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
>>For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
>>Some relevant FAQs on JSP/Servlets can be found at:
>>
>> http://java.sun.com/products/jsp/faq.html
>> http://www.esperanto.org.nz/jsp/jspfaq.html
>> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
>> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>>
>
> ===========================================================================
> To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
> For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
> Some relevant FAQs on JSP/Servlets can be found at:
>
> http://java.sun.com/products/jsp/faq.html
> http://www.esperanto.org.nz/jsp/jspfaq.html
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>
>
--
Hans Bergsten [EMAIL PROTECTED]
Gefion Software http://www.gefionsoftware.com
Author of JavaServer Pages (O'Reilly), http://TheJSPBook.com
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
