TagAttributeInfo (Java EE 5 SDK)

javax.servlet.jsp.tagext Class TagAttributeInfo

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

public class TagAttributeInfo

extends Object

Information on the attributes of a Tag, available at translation time. This class is instantiated from the Tag Library Descriptor file (TLD).

Only the information needed to generate code is included here. Other information like SCHEMA for validation belongs elsewhere.

Note from the Expert Group:
This should have been designed as an interface. Every time we change the TLD, we need to add a new constructor to this class (not good). This class should only be instantiated by container implementations (not by JSP developers).

ID

public static final String ID

"id" is wired in to be ID. There is no real benefit in having it be something else IDREFs are not handled any differently.

另请参见:

常量字段

TagAttributeInfo

public TagAttributeInfo(String name,
                        boolean required,
                        String type,
                        boolean reqTime)

Constructor for TagAttributeInfo. This class is to be instantiated only from the TagLibrary code under request from some JSP code that is parsing a TLD (Tag Library Descriptor).

参数:

name - The name of the attribute.

required - If this attribute is required in tag instances.

type - The name of the type of the attribute.

reqTime - Whether this attribute holds a request-time Attribute.

TagAttributeInfo

public TagAttributeInfo(String name,
                        boolean required,
                        String type,
                        boolean reqTime,
                        boolean fragment)

JSP 2.0 Constructor for TagAttributeInfo. This class is to be instantiated only from the TagLibrary code under request from some JSP code that is parsing a TLD (Tag Library Descriptor).

参数:

name - The name of the attribute.

required - If this attribute is required in tag instances.

type - The name of the type of the attribute.

reqTime - Whether this attribute holds a request-time Attribute.

fragment - Whether this attribute is of type JspFragment

从以下版本开始:

JSP 2.0

TagAttributeInfo

public TagAttributeInfo(String name,
                        boolean required,
                        String type,
                        boolean reqTime,
                        boolean fragment,
                        String description,
                        boolean deferredValue,
                        boolean deferredMethod,
                        String expectedTypeName,
                        String methodSignature)

JSP 2.1 Constructor for TagAttributeInfo. This class is to be instantiated only from the TagLibrary code under request from some JSP code that is parsing a TLD (Tag Library Descriptor).

参数:

name - The name of the attribute.

required - If this attribute is required in tag instances.

type - The name of the type of the attribute.

reqTime - Whether this attribute holds a request-time Attribute.

fragment - Whether this attribute is of type JspFragment

description - The description of the attribute.

deferredValue - Whether this attribute is a deferred value.

deferredMethod - Whether this attribute is a deferred method. rtexpr or deferred value.

expectedTypeName - The name of the expected type of this deferred value (or null if this is not a deferred value).

methodSignature - The expected method signature of this deferred method (or null if this is not a deferred method).

从以下版本开始:

JSP 2.1

getName

public String getName()

The name of this attribute.

返回:

the name of the attribute

getTypeName

public String getTypeName()

The type (as a String) of this attribute.

This method must return "javax.el.ValueExpression" if isDeferredValue() returns true and canBeRequestTime() returns false. It must return "javax.el.MethodExpression" if isDeferredMethod() returns true. It must return "java.lang.Object" if isDeferredValue() returns true and canBeRequestTime() returns true.

返回:

the type of the attribute

canBeRequestTime

public boolean canBeRequestTime()

Whether this attribute has been specified in the TLD as rtexprvalue. If true, this means the attribute can hold a request-time value.

返回:

true if the attribute has been specified in the TLD as rtexprvalue

isRequired

public boolean isRequired()

Whether this attribute is required.

返回:

if the attribute is required.

getIdAttribute

public static TagAttributeInfo getIdAttribute(TagAttributeInfo[] a)

Convenience static method that goes through an array of TagAttributeInfo objects and looks for "id".

参数:

a - An array of TagAttributeInfo

返回:

The TagAttributeInfo reference with name "id"

isFragment

public boolean isFragment()

Whether this attribute is of type JspFragment.

返回:

if the attribute is of type JspFragment

从以下版本开始:

JSP 2.0

getDescription

public String getDescription()

Gets the description string of this tag attribute.

返回:

the description string of this tag attribute

isDeferredValue

public boolean isDeferredValue()

Returns true if this attribute is to be passed a ValueExpression so that expression evaluation can be deferred.

If this method returns true, then getTypeName() must return "javax.el.ValueExpression".

The getExpectedType() method can be used to retrieve the expected type this value expression will be constructed with.

返回:

true if this attribute accepts a deferred value; false otherwise.

从以下版本开始:

JSP 2.1

isDeferredMethod

public boolean isDeferredMethod()

Returns true if this attribute is to be passed a MethodExpression so that expression evaluation can be deferred.

If this method returns true, then getTypeName() must return "javax.el.MethodExpression".

The getMethodSignature() method can be used to retrieve the expected method signature this method expression will be constructed with.

返回:

true if this attribute accepts a deferred method; false otherwise.

从以下版本开始:

JSP 2.1

getExpectedTypeName

public String getExpectedTypeName()

Returns the name of the expected type (as a String) of this deferred value attribute.

This method returns null if isDeferredValue() returns false.

返回:

the name of the expected type

从以下版本开始:

JSP 2.1

getMethodSignature

public String getMethodSignature()

Returns the expected method signature of this deferred method attribute.

This method returns null if isDeferredMethod() returns false.

返回:

the method signature

从以下版本开始:

JSP 2.1

toString

public String toString()

Returns a String representation of this TagAttributeInfo, suitable for debugging purposes.

重写:

toString in class Object

返回:

a String representation of this TagAttributeInfo

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