Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.
The id attribute is deprecated in Struts 2.1.x, and has been replaced by the var attribute.
The begin, end and step attributes are only available from 2.1.7 on
Description
Iterator will iterate over a value. An iterable value can be any of: java.util.Collection, java.util.Iterator, java.util.Enumeration, java.util.Map, or an array.
Parameters
Dynamic Attributes Allowed:false | |||||
Name | Required | Default | Evaluated | Type | Description |
|---|---|---|---|---|---|
| begin | false | 0 | false | Integer | if specified the iteration will start on that index |
| end | false | Size of the 'values' List or array, or 0 if 'step' is negative | false | Integer | if specified the iteration will end on that index(inclusive) |
| id | false | false | String | Deprecated. Use 'var' instead | |
| status | false | false | false | Boolean | If specified, an instanceof IteratorStatus will be pushed into stack upon each iteration |
| step | false | 1 | false | Integer | if specified the iteration index will be increased by this value on each iteration. It can be a negative value, in which case 'begin' must be greater than 'end' |
| value | false | false | String | the iteratable source to iterate over, else an the object itself will be put into a newly created List | |
| var | false | false | String | Name used to reference the value pushed into the Value Stack | |
Examples
The following example retrieves the value of the getDays() method of the current object on the value stack and uses it to iterate over. The <s:property/> tag prints out the current value of the iterator.
The following example uses a Bean tag and places it into the ActionContext. The iterator tag will retrieve that object from the ActionContext and then calls its getDays() method as above. The status attribute is also used to create an IteratorStatus object, which in this example, its odd() method is used to alternate row colours:
The next example will further demonstrate the use of the status attribute, using a DAO obtained from the action class through OGNL, iterating over groups and their users (in a security context). The last() method indicates if the current object is the last available in the iteration, and if not, we need to separate the users using a comma:
The next example iterates over a an action collection and passes every iterator value to another action. The trick here lies in the use of the '[0]' operator. It takes the current iterator value and passes it on to the edit action. Using the '[0]' operator has the same effect as using <s:property />. (The latter, however, does not work from inside the param tag).
A loop that iterates 5 times
Another way to create a simple loop, similar to JSTL's <c:forEach begin="..." end="..." ...> is to use some OGNL magic, which provides some under-the-covers magic to make 0-n loops trivial. This example also loops five times.
A loop that iterates over a partial list