public class IteratorGeneratorTag extends StrutsBodyTagSupport
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.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.
IteratorGenerator
,
Serialized FormModifier and Type | Field and Description |
---|---|
static String |
DEFAULT_SEPARATOR |
Constructor and Description |
---|
IteratorGeneratorTag() |
Modifier and Type | Method and Description |
---|---|
protected void |
clearTagStateForTagPoolingServers()
Provide a mechanism to clear tag state, to handle servlet container JSP tag pooling
behaviour with some servers, such as Glassfish.
|
int |
doEndTag() |
int |
doStartTag() |
void |
setConverter(String aConverter) |
void |
setCount(String count) |
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 |
setVal(String val)
@s.tagattribute required="true"
description="the source to be parsed into an iterator"
|
void |
setVar(String var) |
findString, findValue, findValue, getBody, getPerformClearTagStateForTagPoolingServers, getStack, release, toString
doAfterBody, doInitBody, getBodyContent, getPreviousOut, setBodyContent
findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue
public static final String DEFAULT_SEPARATOR
public void setCount(String count)
public void setSeparator(String separator)
separator
- the seperatorpublic void setVal(String val)
val
- the valuepublic void setConverter(String aConverter)
public void setVar(String var)
public void setPerformClearTagStateForTagPoolingServers(boolean performClearTagStateForTagPoolingServers)
StrutsBodyTagSupport
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.
setPerformClearTagStateForTagPoolingServers
in class StrutsBodyTagSupport
performClearTagStateForTagPoolingServers
- true if tag state should be cleared, false otherwise.public int doStartTag() throws javax.servlet.jsp.JspException
doStartTag
in interface javax.servlet.jsp.tagext.Tag
doStartTag
in class javax.servlet.jsp.tagext.BodyTagSupport
javax.servlet.jsp.JspException
public int doEndTag() throws javax.servlet.jsp.JspException
doEndTag
in interface javax.servlet.jsp.tagext.Tag
doEndTag
in class StrutsBodyTagSupport
javax.servlet.jsp.JspException
protected void clearTagStateForTagPoolingServers()
StrutsBodyTagSupport
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.
clearTagStateForTagPoolingServers
in class StrutsBodyTagSupport
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