org.apache.reef.tang

Interface JavaClassHierarchy

All Superinterfaces:

ClassHierarchy

All Known Implementing Classes:

ClassHierarchyImpl

public interface JavaClassHierarchy
extends ClassHierarchy

Method Summary

Methods

Modifier and Type	Method and Description
Class<?>	classForName(String name)
Node	getNode(Class<?> c) Look up a class object in this ClassHierarchy.
<T> T	parse(NamedParameterNode<T> name, String value) Parse a string value that has been passed into a named parameter.
<T> T	parseDefaultValue(NamedParameterNode<T> name) Obtain a parsed instance of the default value of a named parameter.

Methods inherited from interface org.apache.reef.tang.ClassHierarchy

getNamespace, getNode, isImplementation, merge

Method Detail

getNode

Node getNode(Class<?> c)

Look up a class object in this ClassHierarchy. Unlike the version that takes a string in ClassHierarchy, this version does not throw NameResolutionException.

The behavior of this method is undefined if the provided Class object is not from the ClassLoader (or an ancestor of the ClassLoader) associated with this JavaClassHierarchy. By default, Tang uses the default runtime ClassLoader as its root ClassLoader, so static references (expressions like getNode(Foo.class)) are safe.

Parameters:

c - The class to be looked up in the class hierarchy.

Returns:

The associated NamedParameterNode or ClassNode.

classForName

Class<?> classForName(String name)
                      throws ClassNotFoundException

Throws:

ClassNotFoundException

parse

<T> T parse(NamedParameterNode<T> name,
          String value)
        throws ParseException

Parse a string value that has been passed into a named parameter.

Type Parameters:

T - A type

Parameters:

name - The named parameter that will receive the value.

value - A string value to be validated and parsed.

Returns:

An instance of T, or a ClassNode<? extends T>.

Throws:

ParseException - if the value failed to parse, or parsed to the wrong type (such as when it specifies a class that does not implement or extend T).

parseDefaultValue

<T> T parseDefaultValue(NamedParameterNode<T> name)
                    throws ClassHierarchyException

Obtain a parsed instance of the default value of a named parameter.

Type Parameters:

T - A type

Parameters:

name - The named parameter that should be checked for a default instance.

Returns:

The default instance or null, unless T is a set type. If T is a set, then this method returns a (potentially empty) set of default instances.

Throws:

ClassHierarchyException - if an instance failed to parse.