javax.servlet.jsp.tagext

Class TagAdapter

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: 2.0

Constructor Summary
TagAdapter(SimpleTag adaptee)
Creates a new TagAdapter that wraps the given SimpleTag and returns the parent tag when getParent() is called.
Method Summary
intdoEndTag()
Must not be called.
intdoStartTag()
Must not be called.
JspTaggetAdaptee()
Gets the tag that is being adapted to the Tag interface.
TaggetParent()
Returns the parent of this tag, which is always getAdaptee().getParent().
voidrelease()
Must not be called.
voidsetPageContext(PageContext pc)
Must not be called.
voidsetParent(Tag parentTag)
Must not be called.

Constructor Detail

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.

Method Detail

doEndTag

public int doEndTag()
Must not be called.

Returns: always throws UnsupportedOperationException

Throws: UnsupportedOperationException Must not be called JspException never thrown

doStartTag

public int doStartTag()
Must not be called.

Returns: always throws UnsupportedOperationException

Throws: UnsupportedOperationException Must not be called JspException never thrown

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

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).

Returns: The parent of the tag being adapted.

release

public void release()
Must not be called.

Throws: UnsupportedOperationException Must not be called

setPageContext

public void setPageContext(PageContext pc)
Must not be called.

Parameters: pc ignored.

Throws: UnsupportedOperationException Must not be called

setParent

public void setParent(Tag parentTag)
Must not be called. The parent of this tag is always getAdaptee().getParent().

Parameters: parentTag ignored.

Throws: UnsupportedOperationException Must not be called.

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