javax.servlet.jsp.tagext
类 TagSupport

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

所有已实现的接口：

Serializable, IterationTag, JspTag, Tag

直接已知子类：

BodyTagSupport

public class TagSupport
extends Object
implements IterationTag, 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.

另请参见：

序列化表格

字段摘要

protected String	id The value of the id attribute of this tag; or null.
protected PageContext	pageContext The PageContext.

从接口 javax.servlet.jsp.tagext.IterationTag 继承的字段

EVAL_BODY_AGAIN

从接口 javax.servlet.jsp.tagext.Tag 继承的字段

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

构造方法摘要

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

方法摘要

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, Class klass) Find the instance of a given class type that is closest to a given instance.
String	getId() The value of the id attribute of this tag; or null.
Tag	getParent() The Tag instance most closely enclosing this tag instance.
Object	getValue(String k) Get a the value associated with a key.
Enumeration<String>	getValues() Enumerate the keys for the values kept by this tag handler.
void	release() Release state.
void	removeValue(String k) Remove a value associated with a key.
void	setId(String id) Set the id attribute for this tag.
void	setPageContext(PageContext pageContext) Set the page context.
void	setParent(Tag t) Set the nesting tag of this tag.
void	setValue(String k, Object o) Associate a value with a String key.

从类 java.lang.Object 继承的方法

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

字段详细信息

id

protected String id

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

pageContext

protected PageContext pageContext

The PageContext.

构造方法详细信息

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.

方法详细信息

findAncestorWithClass

public static final Tag findAncestorWithClass(Tag from,
                                              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.

参数：

from - The instance from where to start looking.

klass - The subclass of Tag or interface to be matched

返回：

the nearest ancestor that implements the interface or is an instance of the class specified

doStartTag

public int doStartTag()
               throws JspException

Default processing of the start tag, returning SKIP_BODY.

指定者：

接口 Tag 中的 doStartTag

返回：

SKIP_BODY

抛出：

JspException - if an error occurs while processing this tag

另请参见：

Tag.doStartTag()

doEndTag

public int doEndTag()
             throws JspException

Default processing of the end tag returning EVAL_PAGE.

指定者：

接口 Tag 中的 doEndTag

返回：

EVAL_PAGE

抛出：

JspException - if an error occurs while processing this tag

另请参见：

Tag.doEndTag()

doAfterBody

public int doAfterBody()
                throws JspException

Default processing for a body.

指定者：

接口 IterationTag 中的 doAfterBody

返回：

SKIP_BODY

抛出：

JspException - if an error occurs while processing this tag

另请参见：

IterationTag.doAfterBody()

release

public void release()

Release state.

指定者：

接口 Tag 中的 release

另请参见：

Tag.release()

setParent

public void setParent(Tag t)

Set the nesting tag of this tag.

指定者：

接口 Tag 中的 setParent

参数：

t - The parent Tag.

另请参见：

Tag.setParent(Tag)

getParent

public Tag getParent()

The Tag instance most closely enclosing this tag instance.

指定者：

接口 Tag 中的 getParent

返回：

the parent tag instance or null

另请参见：

Tag.getParent()

setId

public void setId(String id)

Set the id attribute for this tag.

参数：

id - The String for the id.

getId

public String getId()

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

返回：

the value of the id attribute, or null

setPageContext

public void setPageContext(PageContext pageContext)

Set the page context.

指定者：

接口 Tag 中的 setPageContext

参数：

pageContext - The PageContext.

另请参见：

Tag.setPageContext(javax.servlet.jsp.PageContext)

setValue

public void setValue(String k,
                     Object o)

Associate a value with a String key.

参数：

k - The key String.

o - The value to associate.

getValue

public Object getValue(String k)

Get a the value associated with a key.

参数：

k - The string key.

返回：

The value associated with the key, or null.

removeValue

public void removeValue(String k)

Remove a value associated with a key.

参数：

k - The string key.

getValues

public Enumeration<String> getValues()

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

返回：

An enumeration of all the keys for the values set, or null or an empty Enumeration if no values have been set.