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
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
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected void
Provide a mechanism to clear tag state, to handle servlet container JSP tag pooling behaviour with some servers, such as Glassfish.int
doEndTag()
int
void
void
setDecider
(String decider) void
setPerformClearTagStateForTagPoolingServers
(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.void
void
@s.tagattribute required="false" type="Integer" description="Indicate the starting index (eg.void
Methods inherited from class org.apache.struts2.views.jsp.StrutsBodyTagSupport
findString, findValue, findValue, getBody, getPerformClearTagStateForTagPoolingServers, getStack, release, toString
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
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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:StrutsBodyTagSupport
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. 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:
setPerformClearTagStateForTagPoolingServers
in 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:
doStartTag
in interfacejakarta.servlet.jsp.tagext.Tag
- Overrides:
doStartTag
in 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:
doEndTag
in interfacejakarta.servlet.jsp.tagext.Tag
- Overrides:
doEndTag
in classStrutsBodyTagSupport
- Throws:
jakarta.servlet.jsp.JspException
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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 classStrutsBodyTagSupport
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