I remember last year, someone wanted to do the same thing... and he succeeded by patching ognl.
Looking at the link you provided, it seems that one can simply do a OgnlRuntime.setNullHandler. Have you tried that? However, an additional configuration point for this ognl setting would be nice... According to http://jakarta.apache.org/tapestry/tapestry/hivedocs/module/tapestry.ognl.html we only support custom property accessors. Please add a bug report for this... >From Angelo Luis <[EMAIL PROTECTED]>: > In webwork if the property is null the ww construct the object, and i think > that's use OGNL to do this, > http://www.opensymphony.com/ognl/html/DeveloperGuide/nullHandler.html ... > > > This is the part of WW in Action (Manning) that talk about that... Maybe, > Tapestry implement htis some day (as soon as possible, hehe) > > As you become more familiar with writing WebWork applications, you'll often > find > yourself setting the values of properties using complex expressions. For > instance, > if you need to write a page that asks for Kermit's name, his father's name, > and his > grandfather's name, you can do one of two things: > � Set the properties name, fatherName, and grandfatherName in your > action, > and then write code that creates three Muppets, sets their names, and > reconnects > their relationships. > � Set the properties kermit.name, kermit.father.name, and > kermit.father.father.name, and include a single Muppet object, kermit, in > your action. > Clearly, the second choice is simple: It involves only one property in your > action > instead of three, and it doesn't require you to reconstruct the objects. But > how? > Recall that there is no constructor in Muppet that places stubs for the > father property, > which means that attempting to set kermit.father.name with a value will > result in a NullPointerException. > This is where OGNL steps in. It provides a way to swap in a null object with > a > real object whenever access to a property on a null object is detected. With > Web- > Work's assistance, OGNL essentially constructs the object graph of the > son-fathergrandfather relationship automatically, reducing the code you need > to write. > > On 4/24/06, Geoff Longman <[EMAIL PROTECTED]> wrote: > > > > The ognl expression translates into java calls. > > > > So client.address.street would translate into > > > > getClient().getAddress().getStreet() > > > > if getClient() or getAddress() return null, boom you get an NPE. > > > > I doubt that if webwork is using OGNL that the behaviour there is any > > different from what I have described. > > > > Geoff > > > > On 4/24/06, Angelo Luis <[EMAIL PROTECTED]> wrote: > > > I have a Client that have a Adrress and i want to navigate in the object > > > graph in that way : client.address.street, without have a null pointer > > > exception... how can i do that... > > > > > > I kwon that i can do that with webwork. is that a way to do in > > tapestry??? > > > Both (tapestry and ww) uses OGNL, so .... > > > > > > PS; sorry for my english! > > > > > > > > > > > > -- > > The Spindle guy. http://spindle.sf.net > > Blog: http://jroller.com/page/glongman > > Other interests: http://www.squidoo.com/spaceelevator/ > > > > --------------------------------------------------------------------- > > 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]
