Class 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
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:
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Field Summary
Fields inherited from class jakarta.servlet.jsp.tagext.BodyTagSupport
bodyContentFields inherited from class jakarta.servlet.jsp.tagext.TagSupport
id, pageContextFields inherited from interface jakarta.servlet.jsp.tagext.BodyTag
EVAL_BODY_BUFFERED, EVAL_BODY_TAGFields inherited from interface jakarta.servlet.jsp.tagext.IterationTag
EVAL_BODY_AGAINFields inherited from interface jakarta.servlet.jsp.tagext.Tag
EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected voidProvide a mechanism to clear tag state, to handle servlet container JSP tag pooling behaviour with some servers, such as Glassfish.intdoEndTag()intvoidvoidsetDecider(String decider) voidsetPerformClearTagStateForTagPoolingServers(boolean performClearTagStateForTagPoolingServers) Request that the tag state be cleared duringStrutsBodyTagSupport.doEndTag()processing, which may help with certain edge cases with tag logic running on servers that implement JSP Tag Pooling.voidvoid@s.tagattribute required="false" type="Integer" description="Indicate the starting index (eg.voidMethods inherited from class org.apache.struts2.views.jsp.StrutsBodyTagSupport
findString, findValue, findValue, getBody, getPerformClearTagStateForTagPoolingServers, getStack, release, toStringMethods inherited from class jakarta.servlet.jsp.tagext.BodyTagSupport
doAfterBody, doInitBody, getBodyContent, getPreviousOut, setBodyContentMethods inherited from class jakarta.servlet.jsp.tagext.TagSupport
findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValueMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface jakarta.servlet.jsp.tagext.Tag
getParent, setPageContext, setParent
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Constructor Details
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SubsetIteratorTag
public SubsetIteratorTag()
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Method Details
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setCount
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setSource
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setStart
@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
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setDecider
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setVar
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setPerformClearTagStateForTagPoolingServers
public void setPerformClearTagStateForTagPoolingServers(boolean performClearTagStateForTagPoolingServers) Description copied from class:StrutsBodyTagSupportRequest that the tag state be cleared duringStrutsBodyTagSupport.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 classStrutsBodyTagSupport, and this methodStrutsBodyTagSupport.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:
setPerformClearTagStateForTagPoolingServersin classStrutsBodyTagSupport- Parameters:
performClearTagStateForTagPoolingServers- true if tag state should be cleared, false otherwise.
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doStartTag
public int doStartTag() throws jakarta.servlet.jsp.JspException- Specified by:
doStartTagin interfacejakarta.servlet.jsp.tagext.Tag- Overrides:
doStartTagin classjakarta.servlet.jsp.tagext.BodyTagSupport- Throws:
jakarta.servlet.jsp.JspException
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doEndTag
public int doEndTag() throws jakarta.servlet.jsp.JspException- Specified by:
doEndTagin interfacejakarta.servlet.jsp.tagext.Tag- Overrides:
doEndTagin classStrutsBodyTagSupport- Throws:
jakarta.servlet.jsp.JspException
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clearTagStateForTagPoolingServers
protected void clearTagStateForTagPoolingServers()Description copied from class:StrutsBodyTagSupportProvide 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:
clearTagStateForTagPoolingServersin classStrutsBodyTagSupport
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