javax.servlet.jsp.tagext

Class TagData

public class TagData extends Object implements Cloneable

The (translation-time only) attribute/value information for a tag instance.

TagData is only used as an argument to the isValid, validate, and getVariableInfo methods of TagExtraInfo, which are invoked at translation time.

Field Summary
static ObjectREQUEST_TIME_VALUE
Distinguished value for an attribute to indicate its value is a request-time expression (which is not yet available because TagData instances are used at translation-time).
Constructor Summary
TagData(Object[][] atts)
Constructor for TagData.
TagData(Hashtable attrs)
Constructor for a TagData.
Method Summary
ObjectgetAttribute(String attName)
The value of the attribute.
EnumerationgetAttributes()
Enumerates the attributes.
StringgetAttributeString(String attName)
Get the value for a given attribute.
StringgetId()
The value of the tag's id attribute.
voidsetAttribute(String attName, Object value)
Set the value of an attribute.

Field Detail

REQUEST_TIME_VALUE

public static final Object REQUEST_TIME_VALUE
Distinguished value for an attribute to indicate its value is a request-time expression (which is not yet available because TagData instances are used at translation-time).

Constructor Detail

TagData

public TagData(Object[][] atts)
Constructor for TagData.

A typical constructor may be

 static final Object[][] att = {{"connection", "conn0"}, {"id", "query0"}};
 static final TagData td = new TagData(att);
 
All values must be Strings except for those holding the distinguished object REQUEST_TIME_VALUE.

Parameters: atts the static attribute and values. May be null.

TagData

public TagData(Hashtable attrs)
Constructor for a TagData. If you already have the attributes in a hashtable, use this constructor.

Parameters: attrs A hashtable to get the values from.

Method Detail

getAttribute

public Object getAttribute(String attName)
The value of the attribute. If a static value is specified for an attribute that accepts a request-time attribute expression then that static value is returned, even if the value is provided in the body of a action. The distinguished object REQUEST_TIME_VALUE is only returned if the value is specified as a request-time attribute expression or via the <jsp:attribute> action with a body that contains dynamic content (scriptlets, scripting expressions, EL expressions, standard actions, or custom actions). Returns null if the attribute is not set.

Parameters: attName the name of the attribute

Returns: the attribute's value

getAttributes

public Enumeration getAttributes()
Enumerates the attributes.

Returns: An enumeration of the attributes in a TagData

getAttributeString

public String getAttributeString(String attName)
Get the value for a given attribute.

Parameters: attName the name of the attribute

Returns: the attribute value string

Throws: ClassCastException if attribute value is not a String

getId

public String getId()
The value of the tag's id attribute.

Returns: the value of the tag's id attribute, or null if no such attribute was specified.

setAttribute

public void setAttribute(String attName, Object value)
Set the value of an attribute.

Parameters: attName the name of the attribute value the value.

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