Class ImportHandler

java.lang.Object

jakarta.el.ImportHandler

public class ImportHandler
extends Object

Manages class and package imports for EL expressions, similar to Java import statements. The ImportHandler resolves unqualified class names to their fully qualified counterparts, supports static imports, and maintains a set of standard packages that are automatically available in EL expressions.

Since:

EL 3.0

Constructor Summary

Constructors

Constructor	Description
ImportHandler()	Constructs an ImportHandler with the java.lang package pre-imported.

Method Summary

Modifier and Type	Method	Description
void	importClass(String name)	Imports a class so it can be referenced by its simple name in EL expressions.
void	importPackage(String name)	Imports all classes from a package so they can be referenced by their simple names in EL expressions.
void	importStatic(String name)	Imports a static field or method so it can be referenced by its simple name in EL expressions.
Class<?>	resolveClass(String name)	Resolves an unqualified class name to a Class object by searching the registered class imports and package imports.
Class<?>	resolveStatic(String name)	Resolves a statically imported member name to the Class that declares it.

Methods inherited from class Object

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

Constructor Details

ImportHandler

public ImportHandler()

Constructs an ImportHandler with the java.lang package pre-imported. The java.lang package is automatically available in all EL expressions.

Method Details

importStatic

public void importStatic(String name)
                  throws ELException

Imports a static field or method so it can be referenced by its simple name in EL expressions. The argument must be a fully qualified name in the form className.staticMemberName. The static member must be public.

Parameters:

name - the fully qualified name of the static member to import

Throws:

ELException - if the name is invalid, the class cannot be found, the static member does not exist, or the import would be ambiguous

importClass

public void importClass(String name)
                 throws ELException

Imports a class so it can be referenced by its simple name in EL expressions. The argument must be a fully qualified class name. If the simple name conflicts with a previously imported class, an exception is thrown.

Parameters:

name - the fully qualified class name to import

Throws:

ELException - if the class name is invalid or conflicts with an existing import

importPackage

public void importPackage(String name)

Imports all classes from a package so they can be referenced by their simple names in EL expressions. Classes from the imported package are resolved during expression evaluation. If a simple name is ambiguous across multiple imported packages, an ELException is thrown at resolution time.

Parameters:

name - the package name to import

resolveClass

public Class<?> resolveClass(String name)

Resolves an unqualified class name to a Class object by searching the registered class imports and package imports. The name must not contain a dot. Results are cached for performance. If the name is ambiguous across multiple packages, an ELException is thrown.

Parameters:

name - the unqualified class name to resolve

Returns:

the resolved Class, or null if the class cannot be found

Throws:

ELException - if the class name is ambiguous across imported packages

resolveStatic

public Class<?> resolveStatic(String name)

Resolves a statically imported member name to the Class that declares it. The name is the simple name of the static field or method as registered by importStatic(String).

Parameters:

name - the simple name of the static member

Returns:

the declaring Class, or null if not found