WebObjects/Project WONDER/Frameworks/WOOgnl

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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.

Provided your html markup is well-formed, you can also put ognl expressions in standard html tags if you set the following property:

ognl.parseStandardTags=true

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"; }