Package Summary Overview Summary

### class:Types [NONE]
- - public interface Types Utility methods for operating on types. Compatibility Note: Methods may be added to this interface in future releases of the platform. Since: 1.6 See Also: `ProcessingEnvironment.getTypeUtils()` ## Method Summary Modifier and Type Method Description `Element` `asElement (TypeMirror t)` Returns the element corresponding to a type. `TypeMirror` `asMemberOf (DeclaredType containing, Element element)` Returns the type of an element when that element is viewed as a member of, or otherwise directly contained by, a given type. `TypeElement` `boxedClass (PrimitiveType p)` Returns the class of a boxed value of the primitive type argument. `TypeMirror` `capture (TypeMirror t)` Applies capture conversion to a type. `boolean` `contains (TypeMirror t1, TypeMirror t2)` Tests whether one type argument contains another. `List <? extends TypeMirror>` `directSupertypes (TypeMirror t)` Returns the direct supertypes of a type. `TypeMirror` `erasure (TypeMirror t)` Returns the erasure of a type. `ArrayType` `getArrayType (TypeMirror componentType)` Returns an array type with the specified component type. `DeclaredType` `getDeclaredType (TypeElement typeElem, TypeMirror... typeArgs)` Returns the type corresponding to a type element and actual type arguments. `DeclaredType` `getDeclaredType (DeclaredType containing, TypeElement typeElem, TypeMirror... typeArgs)` Returns the type corresponding to a type element and actual type arguments, given a containing type of which it is a member. `NoType` `getNoType (TypeKind kind)` Returns a pseudo-type used where no actual type is appropriate. `NullType` `getNullType()` Returns the null type. `PrimitiveType` `getPrimitiveType (TypeKind kind)` Returns a primitive type. `WildcardType` `getWildcardType (TypeMirror extendsBound, TypeMirror superBound)` Returns a new wildcard type. `boolean` `isAssignable (TypeMirror t1, TypeMirror t2)` Tests whether one type is assignable to another. `boolean` `isSameType (TypeMirror t1, TypeMirror t2)` Tests whether two `TypeMirror` objects represent the same type. `boolean` `isSubsignature (ExecutableType m1, ExecutableType m2)` Tests whether the signature of one method is a subsignature of another. `boolean` `isSubtype (TypeMirror t1, TypeMirror t2)` Tests whether one type is a subtype of another. `PrimitiveType` `unboxedType (TypeMirror t)` Returns the type (a primitive type) of unboxed values of a given type. ## Method Details ### asElement Element asElement (TypeMirror t) Returns the element corresponding to a type. The type may be one of: a `DeclaredType` a `TypeVariable` a pseudo-type for a package or module The method returns `null` if the type is not one with a corresponding element. Types without corresponding elements include: primitive types executable types "none" pseudo-types null types `void` wildcard type argument Parameters: `t` - the type to map to an element Returns: the element corresponding to the given type ### isSameType boolean isSameType (TypeMirror t1, TypeMirror t2) Tests whether two `TypeMirror` objects represent the same type. Caveat: if either of the arguments to this method represents a wildcard, this method will return false. As a consequence, a wildcard is not the same type as itself. This might be surprising at first, but makes sense once you consider that an example like this must be rejected by the compiler:
        List<?> list = new ArrayList<Object>();
           list.add(list.get(0));
Since annotations are only meta-data associated with a type, the set of annotations on either argument is not taken into account when computing whether or not two `TypeMirror` objects are the same type. In particular, two `TypeMirror` objects can have different annotations and still be considered the same. Parameters: `t1` - the first type `t2` - the second type Returns: `true` if and only if the two types are the same ### isSubtype boolean isSubtype (TypeMirror t1, TypeMirror t2) Tests whether one type is a subtype of another. Any type is considered to be a subtype of itself. Parameters: `t1` - the first type `t2` - the second type Returns: `true` if and only if the first type is a subtype of the second Throws: `IllegalArgumentException` - if given a type for an executable, package, or module See Java Language Specification : 4.10 Subtyping ### isAssignable boolean isAssignable (TypeMirror t1, TypeMirror t2) Tests whether one type is assignable to another. Parameters: `t1` - the first type `t2` - the second type Returns: `true` if and only if the first type is assignable to the second Throws: `IllegalArgumentException` - if given a type for an executable, package, or module See Java Language Specification : 5.2 Assignment Contexts ### contains boolean contains (TypeMirror t1, TypeMirror t2) Tests whether one type argument contains another. Parameters: `t1` - the first type `t2` - the second type Returns: `true` if and only if the first type contains the second Throws: `IllegalArgumentException` - if given a type for an executable, package, or module See Java Language Specification : 4.5.1 Type Arguments of Parameterized Types ### isSubsignature boolean isSubsignature (ExecutableType m1, ExecutableType m2) Tests whether the signature of one method is a subsignature of another. Parameters: `m1` - the first method `m2` - the second method Returns: `true` if and only if the first signature is a subsignature of the second See Java Language Specification : 8.4.2 Method Signature ### directSupertypes List<? extends TypeMirror> directSupertypes (TypeMirror t) Returns the direct supertypes of a type. The interface types, if any, will appear last in the list. For an interface type with no direct super-interfaces, a type mirror representing `java.lang.Object` is returned. The type `java.lang.Object` has no direct supertype (JLS 8.1.4, 8.1.5) so an empty list is returned for the direct supertypes of a type mirror representing `java.lang.Object` . Parameters: `t` - the type being examined Returns: the direct supertypes, or an empty list if none Throws: `IllegalArgumentException` - if given a type for an executable, package, or module See Java Language Specification : 4.10 Subtyping ### erasure TypeMirror erasure (TypeMirror t) Returns the erasure of a type. Parameters: `t` - the type to be erased Returns: the erasure of a type Throws: `IllegalArgumentException` - if given a type for a package or module See Java Language Specification : 4.6 Type Erasure ### boxedClass TypeElement boxedClass (PrimitiveType p) Returns the class of a boxed value of the primitive type argument. That is, boxing conversion is applied. Parameters: `p` - the primitive type to be converted Returns: the class of a boxed value of the primitive type argument See Java Language Specification : 5.1.7 Boxing Conversion ### unboxedType PrimitiveType unboxedType (TypeMirror t) Returns the type (a primitive type) of unboxed values of a given type. That is, unboxing conversion is applied. Parameters: `t` - the type to be unboxed Returns: the type of an unboxed value of type `t` Throws: `IllegalArgumentException` - if the given type has no unboxing conversion See Java Language Specification : 5.1.8 Unboxing Conversion ### capture TypeMirror capture (TypeMirror t) Applies capture conversion to a type. Parameters: `t` - the type to be converted Returns: the result of applying capture conversion Throws: `IllegalArgumentException` - if given a type for an executable, package, or module See Java Language Specification : 5.1.10 Capture Conversion ### getPrimitiveType PrimitiveType getPrimitiveType (TypeKind kind) Returns a primitive type. Parameters: `kind` - the kind of primitive type to return Returns: a primitive type Throws: `IllegalArgumentException` - if `kind` is not a primitive kind ### getNullType NullType getNullType() Returns the null type. This is the type of `null`. Returns: the null type ### getNoType NoType getNoType (TypeKind kind) Returns a pseudo-type used where no actual type is appropriate. The kind of type to return may be either `VOID` or `NONE`. To get the pseudo-type corresponding to a package or module, call `asType()` on the element modeling the package or module. Names can be converted to elements for packages or modules using `Elements.getPackageElement(CharSequence)` or `Elements.getModuleElement(CharSequence)`, respectively. Parameters: `kind` - the kind of type to return Returns: a pseudo-type of kind `VOID` or `NONE` Throws: `IllegalArgumentException` - if `kind` is not valid ### getArrayType ArrayType getArrayType (TypeMirror componentType) Returns an array type with the specified component type. Parameters: `componentType` - the component type Returns: an array type with the specified component type Throws: `IllegalArgumentException` - if the component type is not valid for an array ### getWildcardType WildcardType getWildcardType (TypeMirror extendsBound, TypeMirror superBound) Returns a new wildcard type. Either of the wildcard's bounds may be specified, or neither, but not both. Parameters: `extendsBound` - the extends (upper) bound, or `null` if none `superBound` - the super (lower) bound, or `null` if none Returns: a new wildcard type Throws: `IllegalArgumentException` - if bounds are not valid ### getDeclaredType DeclaredType getDeclaredType (TypeElement typeElem, TypeMirror... typeArgs) Returns the type corresponding to a type element and actual type arguments. Given the type element for `Set` and the type mirror for `String`, for example, this method may be used to get the parameterized type `Set<String>`. The number of type arguments must either equal the number of the type element's formal type parameters, or must be zero. If zero, and if the type element is generic, then the type element's raw type is returned. If a parameterized type is being returned, its type element must not be contained within a generic outer class. The parameterized type `Outer<String>.Inner<Number>`, for example, may be constructed by first using this method to get the type `Outer<String>`, and then invoking `getDeclaredType(DeclaredType, TypeElement, TypeMirror...)` . Parameters: `typeElem` - the type element `typeArgs` - the actual type arguments Returns: the type corresponding to a type element and actual type arguments Throws: `IllegalArgumentException` - if too many or too few type arguments are given, or if an inappropriate type argument or type element is provided ### getDeclaredType DeclaredType getDeclaredType (DeclaredType containing, TypeElement typeElem, TypeMirror... typeArgs) Returns the type corresponding to a type element and actual type arguments, given a containing type of which it is a member. The parameterized type `Outer<String>.Inner<Number>`, for example, may be constructed by first using `getDeclaredType(TypeElement, TypeMirror...)` to get the type `Outer<String>`, and then invoking this method. If the containing type is a parameterized type, the number of type arguments must equal the number of `typeElem`'s formal type parameters. If it is not parameterized or if it is `null`, this method is equivalent to `getDeclaredType(typeElem, typeArgs)` . Parameters: `containing` - the containing type, or `null` if none `typeElem` - the type element `typeArgs` - the actual type arguments Returns: the type corresponding to the type element and actual type arguments, contained within the given type Throws: `IllegalArgumentException` - if too many or too few type arguments are given, or if an inappropriate type argument, type element, or containing type is provided ### asMemberOf TypeMirror asMemberOf (DeclaredType containing, Element element) Returns the type of an element when that element is viewed as a member of, or otherwise directly contained by, a given type. For example, when viewed as a member of the parameterized type `Set<String>`, the `Set.add` method is an `ExecutableType` whose parameter is of type `String`. Parameters: `containing` - the containing type `element` - the element Returns: the type of the element as viewed from the containing type Throws: `IllegalArgumentException` - if the element is not a valid one for the given type