java.lang.reflect
Interface WildcardType
- Type
Represents a wildcard type expression, where the type variable
is unnamed. The simplest example of this is
?,
which represents any unbounded type. Another example is
? extends Number, which specifies any type
which is a subclass of
Number (
Number
is the upper bound).
? super String gives the type a less common lower bound,
which means that the type must be either a
String or one
of its superclasses. This can be useful in working with collections.
You may want a method to add instances of a class to a collection
with a more generic type (e.g. adding
Strings to
a list of
Objects), but don't want to allow users
to pass in a collection with a more specific type.
Type[] | getLowerBounds()-
Returns an array of
Types, which specify the
lower bounds of this type.
|
Type[] | getUpperBounds()-
Returns an array of
Types, which specify the
upper bounds of this type.
|
getLowerBounds
public Type[] getLowerBounds()
Returns an array of
Types, which specify the
lower bounds of this type. The default lower bound is
null, which causes this method to return an
empty array.
In generating the array of
Types, each
ParameterizedType or
TypeVariable is
created, (see the documentation for these classes for details of this
process), if necessary, while all other types are simply
resolved.
- an array of
Type objects, representing
the wildcard type's lower bounds.
getUpperBounds
public Type[] getUpperBounds()
Returns an array of
Types, which specify the
upper bounds of this type. The default upper bound is
Object, which causes this method to return an
array, containing just the
Type instance for
Object.
In generating the array of
Types, each
ParameterizedType or
TypeVariable is
created, (see the documentation for these classes for details of this
process), if necessary, while all other types are simply
resolved.
- an array of
Type objects, representing
the wildcard type's upper bounds.
WildcardType.java -- A wildcard type expression e.g. ? extends String
Copyright (C) 2004, 2005 Free Software Foundation, Inc.
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