Class SubsetIteratorTag

java.lang.Object
jakarta.servlet.jsp.tagext.TagSupport
jakarta.servlet.jsp.tagext.BodyTagSupport
org.apache.struts2.views.jsp.StrutsBodyTagSupport
org.apache.struts2.views.jsp.iterator.SubsetIteratorTag
All Implemented Interfaces:
jakarta.servlet.jsp.tagext.BodyTag, jakarta.servlet.jsp.tagext.IterationTag, jakarta.servlet.jsp.tagext.JspTag, jakarta.servlet.jsp.tagext.Tag, Serializable

public class SubsetIteratorTag extends StrutsBodyTagSupport
NOTE: JSP-TAG

A tag that takes an iterator and outputs a subset of it. It delegates to SubsetIteratorFilter internally to perform the subset functionality.

  • count (Object) - Indicate the number of entries to be in the resulting subset iterator
  • source* (Object) - Indicate the source of which the resulting subset iterator is to be derived base on
  • start (Object) - Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator
  • decider (Object) - Extension to plug-in a decider to determine if that particular entry is to be included in the resulting subset iterator
  • var (String) - Indicate the pageContext attribute name to store the resultant subset iterator in
 
 public class MySubsetTagAction extends ActionSupport {
      public String execute() throws Exception {
         l = new ArrayList();
         l.add(new Integer(1));
         l.add(new Integer(2));
         l.add(new Integer(3));
         l.add(new Integer(4));
         l.add(new Integer(5));
         return "done";
      }


      public Integer[] getMyArray() {
         return a;
      }

      public List getMyList() {
         return l;
       }

      public Decider getMyDecider() {
      return new Decider() {
          public boolean decide(Object element) throws Exception {
              int i = ((Integer)element).intValue();
              return (((i % 2) == 0)?true:false);
          }
      };
      }
  }
 
 
 
 <!-- s: List basic -->
    <s:subset source="myList">
       <s:iterator>
          <s:property />
       </s:iterator>
    </s:subset>
 
 
 
 <!-- B: List with count -->
    <s:subset source="myList" count="3">
       <s:iterator>
           <s:property />
       </s:iterator>
     </s:subset>
 
 
 
 <!--  C: List with start -->
      <s:subset source="myList" count="13" start="3">
         <s:iterator>
           <s:property />
         </s:iterator>
      </s:subset>
 
 
 
 <!--  D: List with var -->
      <s:subset var="mySubset" source="myList" count="13" start="3" />
      <%
          Iterator i = (Iterator) pageContext.getAttribute("mySubset");
          while(i.hasNext()) {
      %>
      <%=i.next() %>
      <%  } %>
 
 
 
  <!--  D: List with Decider -->
      <s:subset source="myList" decider="myDecider">
             <s:iterator>
                  <s:property />
             </s:iterator>
      </s:subset>
 
 
@s.tag name="subset" tld-body-content="JSP" description="Takes an iterator and outputs a subset of it"
See Also:
  • Field Summary

    Fields inherited from class jakarta.servlet.jsp.tagext.BodyTagSupport

    bodyContent

    Fields inherited from class jakarta.servlet.jsp.tagext.TagSupport

    id, pageContext

    Fields inherited from interface jakarta.servlet.jsp.tagext.BodyTag

    EVAL_BODY_BUFFERED, EVAL_BODY_TAG

    Fields inherited from interface jakarta.servlet.jsp.tagext.IterationTag

    EVAL_BODY_AGAIN

    Fields inherited from interface jakarta.servlet.jsp.tagext.Tag

    EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE
  • Constructor Summary

    Constructors
    Constructor
    Description
     
  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    Provide a mechanism to clear tag state, to handle servlet container JSP tag pooling behaviour with some servers, such as Glassfish.
    int
     
    int
     
    void
     
    void
    setDecider(String decider)
     
    void
    setPerformClearTagStateForTagPoolingServers(boolean performClearTagStateForTagPoolingServers)
    Request that the tag state be cleared during StrutsBodyTagSupport.doEndTag() processing, which may help with certain edge cases with tag logic running on servers that implement JSP Tag Pooling.
    void
    setSource(String source)
     
    void
    @s.tagattribute required="false" type="Integer" description="Indicate the starting index (eg.
    void
     

    Methods inherited from class jakarta.servlet.jsp.tagext.BodyTagSupport

    doAfterBody, doInitBody, getBodyContent, getPreviousOut, setBodyContent

    Methods inherited from class jakarta.servlet.jsp.tagext.TagSupport

    findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface jakarta.servlet.jsp.tagext.Tag

    getParent, setPageContext, setParent
  • Constructor Details

    • SubsetIteratorTag

      public SubsetIteratorTag()
  • Method Details

    • setCount

      public void setCount(String count)
    • setSource

      public void setSource(String source)
    • setStart

      public void setStart(String start)
      @s.tagattribute required="false" type="Integer" description="Indicate the starting index (eg. first entry is 0) of entries in the source to be available as the first entry in the resulting subset iterator"
      Parameters:
      start - start
    • setDecider

      public void setDecider(String decider)
    • setVar

      public void setVar(String var)
    • setPerformClearTagStateForTagPoolingServers

      public void setPerformClearTagStateForTagPoolingServers(boolean performClearTagStateForTagPoolingServers)
      Description copied from class: StrutsBodyTagSupport
      Request that the tag state be cleared during StrutsBodyTagSupport.doEndTag() processing, which may help with certain edge cases with tag logic running on servers that implement JSP Tag Pooling. Note: Even though the Tag classes extend this class StrutsBodyTagSupport, and this method StrutsBodyTagSupport.setPerformClearTagStateForTagPoolingServers(boolean) exists in the method hierarchy, the JSP processing requires us to explicitly override it in every Tag class in order for the Tag handler method to be visible to the JSP processing. Defining a setter in the superclass alone is insufficient (results in "Cannot find a setter method for the attribute").

      See StrutsBodyTagSupport.clearTagStateForTagPoolingServers() for additional details. Warning: Setting this value to true may allow for the desired behaviour, but doing so may violate the JSP specification. Set to true at your own risk.

      Overrides:
      setPerformClearTagStateForTagPoolingServers in class StrutsBodyTagSupport
      Parameters:
      performClearTagStateForTagPoolingServers - true if tag state should be cleared, false otherwise.
    • doStartTag

      public int doStartTag() throws jakarta.servlet.jsp.JspException
      Specified by:
      doStartTag in interface jakarta.servlet.jsp.tagext.Tag
      Overrides:
      doStartTag in class jakarta.servlet.jsp.tagext.BodyTagSupport
      Throws:
      jakarta.servlet.jsp.JspException
    • doEndTag

      public int doEndTag() throws jakarta.servlet.jsp.JspException
      Specified by:
      doEndTag in interface jakarta.servlet.jsp.tagext.Tag
      Overrides:
      doEndTag in class StrutsBodyTagSupport
      Throws:
      jakarta.servlet.jsp.JspException
    • clearTagStateForTagPoolingServers

      protected void clearTagStateForTagPoolingServers()
      Description copied from class: StrutsBodyTagSupport
      Provide a mechanism to clear tag state, to handle servlet container JSP tag pooling behaviour with some servers, such as Glassfish.

      Usage: Override this method in descendant classes to clear any state that might cause issues should the servlet container re-use a cached instance of the tag object. If the descendant class does not declare any new field members then it should not be strictly necessary to call this method there. Typically that means calling the ancestor's ComponentTagSupport.clearTagStateForTagPoolingServers() method first, then resetting instance variables at the current level to their default state.

      Note: If the descendant overrides StrutsBodyTagSupport.doEndTag(), and does not call super.doEndTag(), then the descendant should call this method in the descendant doEndTag() method to ensure consistent clearing of tag state.

      Overrides:
      clearTagStateForTagPoolingServers in class StrutsBodyTagSupport