Package org.joda.convert

Class Types.TypeVariableInvocationHandler

java.lang.Object

org.joda.convert.Types.TypeVariableInvocationHandler

All Implemented Interfaces:

InvocationHandler

Enclosing class:

Types

private static final class Types.TypeVariableInvocationHandler
extends Object
implements InvocationHandler

Invocation handler to work around a compatibility problem between Java 7 and Java 8.

Java 8 introduced a new method getAnnotatedBounds() in the TypeVariable interface, whose return type AnnotatedType[] is also new in Java 8. That means that we cannot implement that interface in source code in a way that will compile on both Java 7 and Java 8. If we include the getAnnotatedBounds() method then its return type means it won't compile on Java 7, while if we don't include the method then the compiler will complain that an abstract method is unimplemented. So instead we use a dynamic proxy to get an implementation. If the method being called on the TypeVariable instance has the same name as one of the public methods of Types.TypeVariableImpl, the proxy calls the same method on its instance of TypeVariableImpl. Otherwise it throws UnsupportedOperationException; this should only apply to getAnnotatedBounds(). This does mean that users on Java 8 who obtain an instance of TypeVariable from TypeResolver#resolveType will not be able to call getAnnotatedBounds() on it, but that should hopefully be rare.

This workaround should be removed at a distant future time when we no longer support Java versions earlier than 8.

Field Summary

Fields

Modifier and Type	Field	Description
private final Types.TypeVariableImpl<?>	typeVariableImpl
private static final Map<String,Method>	typeVariableMethods

Constructor Summary

Constructors

Constructor	Description
TypeVariableInvocationHandler(Types.TypeVariableImpl<?> typeVariableImpl)

Method Summary

Modifier and Type	Method	Description
Object	invoke(Object proxy, Method method, Object[] args)

Methods inherited from class java.lang.Object

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

Field Details

typeVariableMethods

private static final Map<String,Method> typeVariableMethods

typeVariableImpl

private final Types.TypeVariableImpl<?> typeVariableImpl

Constructor Details

TypeVariableInvocationHandler

TypeVariableInvocationHandler(Types.TypeVariableImpl<?> typeVariableImpl)

Method Details

invoke

public Object invoke(Object proxy,
 Method method,
 Object[] args)
              throws Throwable

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable