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javax.servlet.jsp.tagext
Class TagSupport  

java.lang.Object
  javax.servlet.jsp.tagext.TagSupport

All Implemented Interfaces:

IterationTag, JspTag, java.io.Serializable, Tag

Direct Known Subclasses:

BodyTagSupport

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public class TagSupport

extends java.lang.Object

implements IterationTag, java.io.Serializable

A base class for defining new tag handlers implementing Tag.

The TagSupport class is a utility class intended to be used as the base class for new tag handlers. The TagSupport class implements the Tag and IterationTag interfaces and adds additional convenience methods including getter methods for the properties in Tag. TagSupport has one static method that is included to facilitate coordination among cooperating tags.

Many tag handlers will extend TagSupport and only redefine a few methods.

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Field Summary
protected  java.lang.String	id           The value of the id attribute of this tag; or null.
protected  javax.servlet.jsp.PageContext	pageContext           The PageContext.
private  Tag	parent
private  java.util.Hashtable	values

 

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag

EVAL_BODY_AGAIN

 

Fields inherited from interface javax.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

 

Constructor Summary

TagSupport()           Default constructor, all subclasses are required to define only a public constructor with the same signature, and to call the superclass constructor.

 

Method Summary
int	doAfterBody()           Default processing for a body.
int	doEndTag()           Default processing of the end tag returning EVAL_PAGE.
int	doStartTag()           Default processing of the start tag, returning SKIP_BODY.
static Tag	findAncestorWithClass(Tag from, java.lang.Class klass)           Find the instance of a given class type that is closest to a given instance.
java.lang.String	getId()           The value of the id attribute of this tag; or null.
Tag	getParent()           The Tag instance most closely enclosing this tag instance.
java.lang.Object	getValue(java.lang.String k)           Get a the value associated with a key.
java.util.Enumeration	getValues()           Enumerate the keys for the values kept by this tag handler.
void	release()           Release state.
void	removeValue(java.lang.String k)           Remove a value associated with a key.
void	setId(java.lang.String id)           Set the id attribute for this tag.
void	setPageContext(javax.servlet.jsp.PageContext pageContext)           Set the page context.
void	setParent(Tag t)           Set the nesting tag of this tag.
void	setValue(java.lang.String k, java.lang.Object o)           Associate a value with a String key.

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

parent

private Tag parent

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values

private java.util.Hashtable values

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id

protected java.lang.String id

The value of the id attribute of this tag; or null.

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pageContext

protected javax.servlet.jsp.PageContext pageContext

The PageContext.

Constructor Detail

TagSupport

public TagSupport()

Default constructor, all subclasses are required to define only a public constructor with the same signature, and to call the superclass constructor. This constructor is called by the code generated by the JSP translator.

Method Detail

findAncestorWithClass

public static final Tag findAncestorWithClass(Tag from,
                                              java.lang.Class klass)

Find the instance of a given class type that is closest to a given instance. This method uses the getParent method from the Tag interface. This method is used for coordination among cooperating tags.

The current version of the specification only provides one formal way of indicating the observable type of a tag handler: its tag handler implementation class, described in the tag-class subelement of the tag element. This is extended in an informal manner by allowing the tag library author to indicate in the description subelement an observable type. The type should be a subtype of the tag handler implementation class or void. This addititional constraint can be exploited by a specialized container that knows about that specific tag library, as in the case of the JSP standard tag library.

When a tag library author provides information on the observable type of a tag handler, client programmatic code should adhere to that constraint. Specifically, the Class passed to findAncestorWithClass should be a subtype of the observable type.

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doStartTag

public int doStartTag()
               throws javax.servlet.jsp.JspException

Default processing of the start tag, returning SKIP_BODY.

Specified by:

doStartTag in interface Tag

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doEndTag

public int doEndTag()
             throws javax.servlet.jsp.JspException

Default processing of the end tag returning EVAL_PAGE.

Specified by:

doEndTag in interface Tag

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doAfterBody

public int doAfterBody()
                throws javax.servlet.jsp.JspException

Default processing for a body.

Specified by:

doAfterBody in interface IterationTag

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release

public void release()

Release state.

Specified by:

release in interface Tag

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setParent

public void setParent(Tag t)

Set the nesting tag of this tag.

Specified by:

setParent in interface Tag

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getParent

public Tag getParent()

The Tag instance most closely enclosing this tag instance.

Specified by:

getParent in interface Tag

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setId

public void setId(java.lang.String id)

Set the id attribute for this tag.

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getId

public java.lang.String getId()

The value of the id attribute of this tag; or null.

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setPageContext

public void setPageContext(javax.servlet.jsp.PageContext pageContext)

Set the page context.

Specified by:

setPageContext in interface Tag

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setValue

public void setValue(java.lang.String k,
                     java.lang.Object o)

Associate a value with a String key.

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getValue

public java.lang.Object getValue(java.lang.String k)

Get a the value associated with a key.

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removeValue

public void removeValue(java.lang.String k)

Remove a value associated with a key.

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getValues

public java.util.Enumeration getValues()

Enumerate the keys for the values kept by this tag handler.

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> javax >> servlet >> jsp >> [ tagext overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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