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Version 16.1 by yllan on 2009/06/30 02:51
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1 == Overview ==
2
3 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>>http://www.opensymphony.com/ognl/]].
4
5 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.,,
6
7 Here are some examples that demonstrate just a tiny bit of the really cool things you can do:
8
9 * value=",,Hello Mr. + session.user.firstName";,,
10 * value=",,name.length().(#this>100?2**#this:20+#this)";**,,
11 * value=",,#A=new NSMutableArray(),#A.addObject(name),#A";,,
12
13 Here are some examples provided by Max Muller, WOOgnl's original author:
14
15 {{code}}
16
17 // Calling methods with arguments
18 Repetition1: WORepetition {
19 item = arrayItem;
20 list = "~sort(anArray, \"name\")";
21 } 
22
23 {{/code}}
24
25 {{code}}
26
27 // Calling static methods
28 Repetition2: WORepetition {
29 item = arrayItem;
30 list = "~@er.extensions.ERXArrayUtilities@sortedArraySortedWithKey(anArray, \"name\")";
31 }
32
33 {{/code}}
34
35 {{code}}
36
37 // Accessing static ivars
38 String1: WOString {
39 value = "~@ognl.webobjects.WOOgnl@OgnlSpecialCharacters";
40 }
41
42 {{/code}}
43
44 {{code}}
45
46 // Use of conditionals, note that every previous value of the . is
47 // pushed into the ivar #this
48 String2: WOString {
49 value = "~name.length().(#this > 100? 2*#this : 20+#this)";
50 }
51
52 {{/code}}
53
54 {{code}}
55
56 // String concat
57 String3: WOString {
58 value = "~\"Hello Max \" + name";
59 } 
60
61 {{/code}}
62
63 {{code}}
64
65 // Use of set operator in. can also use in against NSArray and
66 NSSet objects
67 String4: WOString {
68 value = "~name in {\"Main\", \"Something\"} ? \"Yes\" : \"No\"";
69 }
70
71 {{/code}}
72
73 {{code}}
74
75 // Variable declaration. Note that commas allow multiple actions
76 // per expression.
77 String5: WOString {
78 value = "~#A=new com.webobjects.foundation.NSMutableArray(),#A.addObject(name), #A.addObjectsFromArray(session.languages), #A";
79 }
80
81 {{/code}}
82
83 === Helper system ===
84
85 For more detail, check [[http://wiki.objectstyle.org/confluence/display/WOL/WOOGNL+Helper+Functions]]. With these two lines in your properties file and Project WONDER,
86
87 {{code}}
88
89 ognl.helperFunctions=true
90 ognl.inlineBindings=true
91
92 {{/code}}
93
94 You can declare your own helper class like this:
95
96 {{code}}
97
98 public class StringHelper {
99 public String capitalize(String str) {
100 // ...
101 }
102 }
103
104 {{/code}}
105
106 And use that in your binding by "piping your data"
107
108 {{code}}
109
110 <wo:str value="$person.name|capitalize" />
111
112 {{/code}}