Class 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
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
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.
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Field Summary
FieldsFields 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()intvoidsetConverter(String aConverter) voidvoidsetPerformClearTagStateForTagPoolingServers(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.voidsetSeparator(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"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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Field Details
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DEFAULT_SEPARATOR
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Constructor Details
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IteratorGeneratorTag
public IteratorGeneratorTag()
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Method Details
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setCount
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setSeparator
@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
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setVal
@s.tagattribute required="true" description="the source to be parsed into an iterator"- Parameters:
val- the value
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setConverter
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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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