java.lang.Object javax.servlet.jsp.tagext.VariableInfoInformation on the scripting variables that are created/modified by a tag (at run-time). This information is provided by TagExtraInfo classes and it is used by the translation phase of JSP.
Scripting variables generated by a custom action have an associated scope of either AT_BEGIN, NESTED, or AT_END.
The class name (VariableInfo.getClassName) in the returned objects
is used to determine the types of the scripting variables.
Note that because scripting variables are assigned their values
from scoped attributes which cannot be of primitive types,
"boxed" types such as
be used instead of primitives.
The class name may be a Fully Qualified Class Name, or a short class name.
If a Fully Qualified Class Name is provided, it should refer to a class that should be in the CLASSPATH for the Web Application (see Servlet 2.4 specification - essentially it is WEB-INF/lib and WEB-INF/classes). Failure to be so will lead to a translation-time error.
If a short class name is given in the VariableInfo objects, then the class name must be that of a public class in the context of the import directives of the page where the custom action appears. The class must also be in the CLASSPATH for the Web Application (see Servlet 2.4 specification - essentially it is WEB-INF/lib and WEB-INF/classes). Failure to be so will lead to a translation-time error.
Frequently a fully qualified class name will refer to a class that is known to the tag library and thus, delivered in the same JAR file as the tag handlers. In most other remaining cases it will refer to a class that is in the platform on which the JSP processor is built (like J2EE). Using fully qualified class names in this manner makes the usage relatively resistant to configuration errors.
A short name is usually generated by the tag library based on some attributes passed through from the custom action user (the author), and it is thus less robust: for instance a missing import directive in the referring JSP page will lead to an invalid short name class and a translation error.
The result of the invocation on getVariableInfo is an array of VariableInfo objects. Each such object describes a scripting variable by providing its name, its type, whether the variable is new or not, and what its scope is. Scope is best described through a picture:
The JSP 2.0 specification defines the interpretation of 3 values:
1 Called after
Variable Synchronization Points
doStartTag() doInitBody() doAfterBody() doEndTag() doTag() Tag
EVAL_BODY_INCLUDEis returned, or after
Variable Information in the TLD
Scripting variable information can also be encoded directly for most cases into the Tag Library Descriptor using the <variable> subelement of the <tag> element. See the JSP specification.
|public static final int||NESTED||Scope information that scripting variable is visible only within the start/end tags.|
|public static final int||AT_BEGIN||Scope information that scripting variable is visible after start tag.|
|public static final int||AT_END||Scope information that scripting variable is visible after end tag.|
public VariableInfo(String varName, String className, boolean declare, int scope)
|Method from javax.servlet.jsp.tagext.VariableInfo Summary:|
|getClassName, getDeclare, getScope, getVarName|
|Methods from java.lang.Object:|
|clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait|
|Method from javax.servlet.jsp.tagext.VariableInfo Detail:|
public String getClassName()
public boolean getDeclare()
public int getScope()
public String getVarName()