Programming__WebObjects-Project WONDER-Frameworks-WOOgnl

Version 9.1 by smmccraw on 2007/07/08 09:45

Overview

OGNL stands for "Object Graph Navigation Language", and it defines an entire family of key-value coding-like abilities. As Jonathan Rentzsch put it in his CAWUG presentation on Project WOnder, "Think: Key-Value Coding on Steroids". You can get more information on the specifics on OGNL at the official OGNL website.

WOOgnl provides a framework that integrates the OGNL syntax into WO's standard binding resolution. By simply including the WOOgnl framework on your build path and preceding your binding value with a "_{", it will be interpreted by WOOgnl.}

Here are some examples that demonstrate just a tiny bit of the really cool things you can do:

value="_{Hello Mr. + session.user.firstName";}
value="_{name.length().(#this>100?2#this:20+#this)";}
value="_{#A=new NSMutableArray(),#A.addObject(name),#A";}

Here are some examples provided by Max Muller, WOOgnl's original author:

   Calling methods with arguments
  Repetition1: WORepetition {
        item = arrayItem;
        list = "sort(anArray, \"name\")";
  }

// Calling static methods

  Repetition2: WORepetition {
        item = arrayItem;
        list = "@er.extensions.ERXArrayUtilities@sortedArraySortedWithKey(anArray, \"name\")";
  }

// Accessing static ivars

  String1: WOString {
        value = "@ognl.webobjects.WOOgnl@OgnlSpecialCharacters";
  }

// Use of conditionals, note that every previous value of the . is

   pushed into the ivar #this
  String2: WOString {
        value = "name.length().(#this > 100? 2*#this : 20+#this)";
  }

// String concat

  String3: WOString {
        value = "\"Hello Max \" + name";
  }

// Use of set operator in. can also use in against NSArray and

  NSSet objects
  String4: WOString {
        value = "name in {\"Main\", \"Something\"} ? \"Yes\" : \"No\"";
  }

// Variable declaration. Note that commas allow multiple actions

   per expression.
  String5: WOString {
        value = "#A=new com.webobjects.foundation.NSMutableArray(),#A.addObject(name), #A.addObjectsFromArray(session.languages), #A";
  }

Category:WebObjects