This is both a solution and a proposal. I had to do the same - except more generally, I wanted to be able to have get any component's html ID and tie it to javascript.
The solution I came up with was to write an "observer" component and have all my components (subclassed from Base, Abstract and AbstractForm) implement an "Observable" interface. The idea is simple. You wrap all components you want to observe with the observer component. The observer registers itself in the request cycle under a well-known name. Observable components can be given html id patterns. In their rendercomponent method, observable components check to see if there is an observer and register themselves. The observer is also smart to tag a unique number (specific to each html id pattern). Upon registration, the observer calls an "observe" method that subclasses of observer override to provide specific funtionality. Finally, once the body of the observer has rendered, it calls a getJS function to generate javascript. In your case, such a solution would involve setting a pattern of "id" for the individual cells and the total field and having the total then use the id to compute the total. Now, in this regard, I do have a TAPESTRY MODIFICATION REQUEST. Actually two: 1) MODIFY BaseComponent, AbstractComponent and AbstractForm to all be one interface. A form comp. should really be smart enough to know if it is being included in a form and not have to rely on a subclass. Here is why - I want to introduce a common parent class or interface for all my components. Well, I have to provide three implementation, one for base, abstract and abstract form. 2) There is no mechanism, that doesn't involve the page to retain state between a rewind and render cycle. The request cycle's map gets cleared between the cycles. Why is this? Can this be modified? Also, I'd suggest the observer pattern be introduced. Cross-component javascript is pretty much impossible without it. -----Original Message----- From: news [mailto:[EMAIL PROTECTED] Behalf Of bobby rullo Sent: Monday, April 04, 2005 6:24 PM To: tapestry-user@jakarta.apache.org Subject: Need to know ALL the form id's of a given element Hi, A relatively common thing you see in a web application is an automatically updating total field. For example you have a bunch of line items and you want the total qty, price, etc. to update automatically whenever the user changes a number. Since this is a common pattern in the app I am creating, and this is Tapestry, I thought I'd make a component. My componenet would look something like this: <span jwcid="@Totaler" componentToTotal="ognl:components.numericFieldQuantity" /> The Totaler component would create javascript that would find all the form fields that the componentToTotal form component rendered and total its values. Sounded easy to me until I realize I can't "get at" all the form element id's that a particular form component may have generated - at least I don't know how to! The cheap way to do this is pass the totaler component a string which would be the prefix of the generated form inputs, and it could just iterate through all the components of the form and find ones that started with that prefix. But that is not very tapestry-like and requires that you make sure you don't have conflicting component names.... The sort of thing I was originally looking for was something like a component render listener - something I could hook into a form component and have it trigger every time it was rendered on a page so I could do a getName() and add it to my list of form id's.... Of course if there is another way to do this I'm open to that too - unless it involves submitting to the server! Thanks in advance, Bobby --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
