Package jakarta.servlet.jsp.tagext
Class TagAdapter
- java.lang.Object
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- jakarta.servlet.jsp.tagext.TagAdapter
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public class TagAdapter extends Object implements Tag
Wraps any SimpleTag and exposes it using a Tag interface. This is used to allow collaboration between classic Tag handlers and SimpleTag handlers.Because SimpleTag does not extend Tag, and because Tag.setParent() only accepts a Tag instance, a classic tag handler (one that implements Tag) cannot have a SimpleTag as its parent. To remedy this, a TagAdapter is created to wrap the SimpleTag parent, and the adapter is passed to setParent() instead. A classic Tag Handler can call getAdaptee() to retrieve the encapsulated SimpleTag instance.
- Since:
- JSP 2.0
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Field Summary
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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 Constructor Description TagAdapter(SimpleTag adaptee)
Creates a new TagAdapter that wraps the given SimpleTag and returns the parent tag when getParent() is called.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
doEndTag()
Must not be called.int
doStartTag()
Must not be called.JspTag
getAdaptee()
Gets the tag that is being adapted to the Tag interface.Tag
getParent()
Returns the parent of this tag, which is always getAdaptee().getParent().void
release()
Must not be called.void
setPageContext(PageContext pc)
Must not be called.void
setParent(Tag parentTag)
Must not be called.
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Constructor Detail
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TagAdapter
public TagAdapter(SimpleTag adaptee)
Creates a new TagAdapter that wraps the given SimpleTag and returns the parent tag when getParent() is called.- Parameters:
adaptee
- The SimpleTag being adapted as a Tag.
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Method Detail
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setPageContext
public void setPageContext(PageContext pc)
Must not be called.- Specified by:
setPageContext
in interfaceTag
- Parameters:
pc
- ignored.- Throws:
UnsupportedOperationException
- Must not be called
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setParent
public void setParent(Tag parentTag)
Must not be called. The parent of this tag is always getAdaptee().getParent().- Specified by:
setParent
in interfaceTag
- Parameters:
parentTag
- ignored.- Throws:
UnsupportedOperationException
- Must not be called.
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getParent
public Tag getParent()
Returns the parent of this tag, which is always getAdaptee().getParent(). This will either be the enclosing Tag (if getAdaptee().getParent() implements Tag), or an adapter to the enclosing Tag (if getAdaptee().getParent() does not implement Tag).- Specified by:
getParent
in interfaceTag
- Returns:
- The parent of the tag being adapted.
- See Also:
TagSupport.findAncestorWithClass(jakarta.servlet.jsp.tagext.Tag, java.lang.Class<?>)
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getAdaptee
public JspTag getAdaptee()
Gets the tag that is being adapted to the Tag interface. This should be an instance of SimpleTag in JSP 2.0, but room is left for other kinds of tags in future spec versions.- Returns:
- the tag that is being adapted
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doStartTag
public int doStartTag() throws JspException
Must not be called.- Specified by:
doStartTag
in interfaceTag
- Returns:
- always throws UnsupportedOperationException
- Throws:
UnsupportedOperationException
- Must not be calledJspException
- never thrown- See Also:
BodyTag
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doEndTag
public int doEndTag() throws JspException
Must not be called.- Specified by:
doEndTag
in interfaceTag
- Returns:
- always throws UnsupportedOperationException
- Throws:
UnsupportedOperationException
- Must not be calledJspException
- never thrown
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release
public void release()
Must not be called.- Specified by:
release
in interfaceTag
- Throws:
UnsupportedOperationException
- Must not be called
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