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org.apache.struts2.components
public class: IteratorComponent [javadoc | source]
java.lang.Object
   org.apache.struts2.components.Component
      org.apache.struts2.components.ContextBean
         org.apache.struts2.components.IteratorComponent

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.

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.


<s:iterator value="days">
  <p>day is: <s:property/></p>
</s: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:



<s:bean name="org.apache.struts2.example.IteratorExample" var="it">
  <s:param name="day" value="'foo'"/>
  <s:param name="day" value="'bar'"/>
</s:bean>

<table border="0" cellspacing="0" cellpadding="1"> <tr> <th>Days of the week</th> </tr>

<s:iterator value="#it.days" status="rowstatus"> <tr> <s:if test="#rowstatus.odd == true"> <td style="background: grey"><s:property/></td> </s:if> <s:else> <td><s:property/></td> </s:else> </tr> </s:iterator> </table>

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:



 <s:iterator value="groupDao.groups" status="groupStatus">
     <tr class="<s:if test="#groupStatus.odd == true ">odd</s:if><s:else>even</s:else>">
         <td><s:property value="name" /></td>
         <td><s:property value="description" /></td>
         <td>
             <s:iterator value="users" status="userStatus">
                 <s:property value="fullName" /><s:if test="!#userStatus.last">,</s:if>
             </s:iterator>
         </td>
     </tr>
 </s:iterator>


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).



     <s:action name="entries" var="entries"/>
     <s:iterator value="#entries.entries" >
         <s:property value="name" />
         <s:property />
         <s:push value="...">
             <s:action name="edit" var="edit" >
                 <s:param name="entry" value="[0]" />
             </s:action>
         </push>
     </s:iterator>


A loop that iterates 5 times


<s:iterator var="counter" begin="1" end="5" >
   <!-- current iteration value (1, ... 5) -->
   <s:property value="top" />
</s:iterator>


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.


<s:iterator status="stat" value="(5).{ #this }" >
   <s:property value="#stat.count" /> <!-- Note that "count" is 1-based, "index" is 0-based. -->
</s:iterator>


A loop that iterates over a partial list


<s:iterator value="{1,2,3,4,5}" begin="2" end="4" >
   <!-- current iteration value (2,3,4) -->
   <s:property value="top" />
</s:iterator>


Nested Class Summary:
class  IteratorComponent.CounterIterator   
Field Summary
protected  Iterator iterator     
protected  IteratorStatus status     
protected  Object oldStatus     
protected  StatusState statusState     
protected  String statusAttr     
protected  String value     
protected  String beginStr     
protected  Integer begin     
protected  String endStr     
protected  Integer end     
protected  String stepStr     
protected  Integer step     
Fields inherited from org.apache.struts2.components.ContextBean:
var
Fields inherited from org.apache.struts2.components.Component:
COMPONENT_STACK,  stack,  parameters,  actionMapper,  throwExceptionOnELFailure
Constructor:
 public IteratorComponent(ValueStack stack) 
Method from org.apache.struts2.components.IteratorComponent Summary:
end,   setBegin,   setEnd,   setStatus,   setStep,   setValue,   start
Methods from org.apache.struts2.components.ContextBean:
getVar,   putInContext,   setId,   setVar
Methods from org.apache.struts2.components.Component:
addAllParameters,   addParameter,   altSyntax,   altSyntax,   completeExpressionIfAltSyntax,   copyParams,   determineActionURL,   determineNamespace,   end,   end,   fieldError,   findAncestor,   findString,   findString,   findStringIfAltSyntax,   findValue,   findValue,   findValue,   getComponentStack,   getParameters,   getStack,   popComponentStack,   setActionMapper,   setThrowExceptionsOnELFailure,   start,   stripExpressionIfAltSyntax,   stripExpressionIfAltSyntax,   toString,   usesBody
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from org.apache.struts2.components.IteratorComponent Detail:
 public boolean end(Writer writer,
    String body) 
 public  void setBegin(String begin) 
 public  void setEnd(String end) 
 public  void setStatus(String status) 
 public  void setStep(String step) 
 public  void setValue(String value) 
 public boolean start(Writer writer)