Class IteratorGeneratorTag

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.IteratorGeneratorTag
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 IteratorGeneratorTag extends StrutsBodyTagSupport
NOTE: JSP-TAG

Generate an iterator based on the val attribute supplied.

NOTE: The generated iterator will ALWAYS be pushed into the top of the stack, and poped at the end of the tag.
  • val* (Object) - the source to be parsed into an iterator
  • count (Object) - the max number (Integer, Float, Double, Long, String) entries to be in the iterator
  • separator (String) - the separator to be used in separating the val into entries of the iterator
  • var (String) - the name to store the resultant iterator into page context, if such name is supplied
  • converter (Object) - the converter (must extends off IteratorGenerator.Converter interface) to convert the String entry parsed from val into an object
Example One:
 Generate a simple iterator
 <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}">
  <s:iterator>
      <s:property /><br/>
  </s:iterator>
 </s:generator>
 
This generates an iterator and print it out using the iterator tag. Example Two:
 Generate an iterator with count attribute
 <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" count="3">
  <s:iterator>
      <s:property /><br/>
  </s:iterator>
 </s:generator>
 
This generates an iterator, but only 3 entries will be available in the iterator generated, namely aaa, bbb and ccc respectively because count attribute is set to 3 Example Three:
 Generate an iterator with var attribute
 <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" count="4" separator="," var="myAtt" />
 <%
  Iterator i = (Iterator) pageContext.getAttribute("myAtt");
  while(i.hasNext()) {
      String s = (String) i.next(); %>
      <%=s%> <br/>
 <%    }
 %>
 
This generates an iterator and put it in the PageContext under the key as specified by the var attribute. Example Four:
 Generate an iterator with comparator attribute
 <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}" converter="%{myConverter}">
  <s:iterator>
      <s:property /><br/>
  </s:iterator>
 </s:generator>


 public class GeneratorTagAction extends ActionSupport {

   ....

   public Converter getMyConverter() {
      return new Converter() {
          public Object convert(String value) throws Exception {
              return "converter-"+value;
          }
      };
   }

   ...

 }
 
This will generate an iterator with each entries decided by the converter supplied. With this converter, it simply add "converter-" to each entries.
See Also:
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
     

    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
    setConverter(String aConverter)
     
    void
     
    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
    setSeparator(String separator)
    @s.tagattribute required="true" type="String" description="the separator to be used in separating the val into entries of the iterator"
    void
    @s.tagattribute required="true" description="the source to be parsed into an iterator"
    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
  • Field Details

  • Constructor Details

    • IteratorGeneratorTag

      public IteratorGeneratorTag()
  • Method Details

    • setCount

      public void setCount(String count)
    • setSeparator

      public void setSeparator(String separator)
      @s.tagattribute required="true" type="String" description="the separator to be used in separating the val into entries of the iterator"
      Parameters:
      separator - the seperator
    • setVal

      public void setVal(String val)
      @s.tagattribute required="true" description="the source to be parsed into an iterator"
      Parameters:
      val - the value
    • setConverter

      public void setConverter(String aConverter)
    • 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