Extending base class and accessing implementation's fields in Struts 2
I have ListBaseObject foo The list is of type BaseObjectImpl BaseObject has fields: String a String b BaseObjectImpl has fields: String c String d Now I'm in a JSP and want to iterate foo (using s:iterator), accessing fields c and d (inside iterator using s:property, for example). How? As far as Struts knows I'm dealing with BaseObject. Is there a way for me to cast to BaseObjectImpl without creating a StrutsTypeConverter for every object I'm extending? In my use case, there will be several and the temptation is to just define the list with the implementation which foils reusability patterns (e.g., ListBaseObjectImpl). Likewise, what to do when posting back to a field like this: BaseObject bar (which has BaseObjectImpl as its implementation) e.g., s:textfield name=bar.c / Is there a totally different approach that would be better or is StrutsTypeConverter the only good answer? - Eric
Re: Extending base class and accessing implementation's fields in Struts 2
You're making OGNL calls against an object; it doesn't care about the type--if you access foo.bar it'll call getBar() on foo, setBar() on submission. Dave On Mon, Dec 3, 2012 at 11:19 AM, Eric Lentz ericle...@outfastsource.com wrote: I have ListBaseObject foo The list is of type BaseObjectImpl BaseObject has fields: String a String b BaseObjectImpl has fields: String c String d Now I'm in a JSP and want to iterate foo (using s:iterator), accessing fields c and d (inside iterator using s:property, for example). How? As far as Struts knows I'm dealing with BaseObject. Is there a way for me to cast to BaseObjectImpl without creating a StrutsTypeConverter for every object I'm extending? In my use case, there will be several and the temptation is to just define the list with the implementation which foils reusability patterns (e.g., ListBaseObjectImpl). Likewise, what to do when posting back to a field like this: BaseObject bar (which has BaseObjectImpl as its implementation) e.g., s:textfield name=bar.c / Is there a totally different approach that would be better or is StrutsTypeConverter the only good answer? - Eric -- e: davelnew...@gmail.com m: 908-380-8699 s: davelnewton_skype t: @dave_newton b: Bucky Bits g: davelnewton so: Dave Newton - To unsubscribe, e-mail: user-unsubscr...@struts.apache.org For additional commands, e-mail: user-h...@struts.apache.org
Re: Extending base class and accessing implementation's fields in Struts 2
I'm almost there. I didn't suspect that it would work that way with the iterator. Should have tried it first! Thanks Dave. On the way back, such as in a post, if BaseObject is an interface or abstract, as I'm hoping for it to be, then Struts tries to instantiate the BaseObject type, which it can't, so it throws: [com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler] Could not create and/or set value back on to object java.lang.InstantiationException at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30) at java.lang.reflect.Constructor.newInstance(Constructor.java:501) at java.lang.Class.newInstance0(Class.java:350) at java.lang.Class.newInstance(Class.java:303) at com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:130) at com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler.createObject(InstantiatingNullHandler.java:159) at com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler.nullPropertyValue(InstantiatingNullHandler.java:137) at com.opensymphony.xwork2.ognl.OgnlNullHandlerWrapper.nullPropertyValue(OgnlNullHandlerWrapper.java:21) at ognl.ASTProperty.getValueBody(ASTProperty.java:118) ...etc. Any ideas on solving that? - Eric On Mon, Dec 3, 2012 at 11:19 AM, Eric Lentz ericle...@outfastsource.comwrote: I have ListBaseObject foo The list is of type BaseObjectImpl BaseObject has fields: String a String b BaseObjectImpl has fields: String c String d Now I'm in a JSP and want to iterate foo (using s:iterator), accessing fields c and d (inside iterator using s:property, for example). How? As far as Struts knows I'm dealing with BaseObject. Is there a way for me to cast to BaseObjectImpl without creating a StrutsTypeConverter for every object I'm extending? In my use case, there will be several and the temptation is to just define the list with the implementation which foils reusability patterns (e.g., ListBaseObjectImpl). Likewise, what to do when posting back to a field like this: BaseObject bar (which has BaseObjectImpl as its implementation) e.g., s:textfield name=bar.c / Is there a totally different approach that would be better or is StrutsTypeConverter the only good answer? - Eric
Re: Extending base class and accessing implementation's fields in Struts 2
2012/12/3 Eric Lentz ericle...@outfastsource.com: I'm almost there. I didn't suspect that it would work that way with the iterator. Should have tried it first! Thanks Dave. On the way back, such as in a post, if BaseObject is an interface or abstract, as I'm hoping for it to be, then Struts tries to instantiate the BaseObject type, which it can't, so it throws: [com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler] Could not create and/or set value back on to object java.lang.InstantiationException at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30) at java.lang.reflect.Constructor.newInstance(Constructor.java:501) at java.lang.Class.newInstance0(Class.java:350) at java.lang.Class.newInstance(Class.java:303) at com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:130) at com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler.createObject(InstantiatingNullHandler.java:159) at com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler.nullPropertyValue(InstantiatingNullHandler.java:137) at com.opensymphony.xwork2.ognl.OgnlNullHandlerWrapper.nullPropertyValue(OgnlNullHandlerWrapper.java:21) at ognl.ASTProperty.getValueBody(ASTProperty.java:118) ...etc. Any ideas on solving that? You can implement your own ObjectTypeDeterminer or you can try to play with @Element Regards -- Łukasz + 48 606 323 122 http://www.lenart.org.pl/ - To unsubscribe, e-mail: user-unsubscr...@struts.apache.org For additional commands, e-mail: user-h...@struts.apache.org
