org.bbottema.javareflection

Class TypeUtils

java.lang.Object

org.bbottema.javareflection.TypeUtils

public final class TypeUtils
extends Object

Utility functions that deal with type information, conversions and autoboxing.

Particularly of interest is generateCompatibleTypeLists(Set, Class[]), which generates a collection of type lists which can be derived from the input type list. This is usful for method matching, since Java reflection doesn't take into account autoboxing, casting or auto widening, let alone type conversions.

Types that are candidates for Autoboxing:

• boolean java.lang.Boolean
• char java.lang.Character
• byte java.lang.Byte
• short java.lang.Short
• int java.lang.Integer
• long java.lang.Long
• float java.lang.Float
• double java.lang.Double

For types that are candidates for common conversion, please see ValueConversionHelper.

Constructor Summary

Constructors

Constructor and Description
TypeUtils()

Method Summary

Modifier and Type	Method and Description
static @Nullable Class<?>	autobox(Class<?> c) Emulates Java's Autoboxing feature; tries to convert a type to its (un)wrapped counter version.
static @NotNull Class<?>[]	collectTypes(Object[] objects) Creates a new array of class objects harvested from an array of objects.
static boolean	containsAnnotation(Annotation[] myListOfAnnotations, Class<? extends Annotation> annotationClass)
static boolean	containsAnnotation(List<Annotation> myListOfAnnotations, Class<? extends Annotation> annotationClass)
static <T extends Annotation> T	findAnnotation(Annotation[] myListOfAnnotations, Class<T> annotationClass)
static <T extends Annotation> T	findAnnotation(Collection<Annotation> myListOfAnnotations, Class<T> annotationClass)
static @NotNull List<Class<?>[]>	generateCompatibleTypeLists(Set<LookupMode> lookupMode, Class<?>... inputTypelist) Initializes the list with type-arrays and starts generating beginning from index 0.
static boolean	isPackage(String name) Validates whether a string represents a valid package.
static boolean	isTypeListCompatible(Class<?>[] inputTypeList, Class<?>[] targetTypeList, Set<LookupMode> lookupMode)
static @NotNull Class<?>	widestNumberClass(Number... numbers) Returns the smallest class that can hold all of the specified numbers.

Methods inherited from class java.lang.Object

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

Constructor Detail

TypeUtils

public TypeUtils()

Method Detail

collectTypes

@NotNull
public static @NotNull Class<?>[] collectTypes(Object[] objects)

Creates a new array of class objects harvested from an array of objects.

NOTE: this method will never return primitive classes (such as double.class, as you can't put primitive values into an array of Objects (they will be autoboxes by the JVM).

Parameters:

objects - The array of objects to harvest classtypes from.

Returns:

The array with the harvested classtypes.

isTypeListCompatible

public static boolean isTypeListCompatible(Class<?>[] inputTypeList,
                                           Class<?>[] targetTypeList,
                                           Set<LookupMode> lookupMode)

generateCompatibleTypeLists

@NotNull
public static @NotNull List<Class<?>[]> generateCompatibleTypeLists(Set<LookupMode> lookupMode,
                                                                             Class<?>... inputTypelist)

Initializes the list with type-arrays and starts generating beginning from index 0. This method is used for (un)wrapping.

Parameters:

lookupMode - Flag indicating the search steps that need to be done.

inputTypelist - The list with original user specified types.

Returns:

The list with converted type-arrays.

autobox

@Nullable
public static @Nullable Class<?> autobox(Class<?> c)

Emulates Java's Autoboxing feature; tries to convert a type to its (un)wrapped counter version.

Parameters:

c - The datatype to convert (autobox).

Returns:

The converted version of the specified type, or null.

widestNumberClass

@NotNull
public static @NotNull Class<?> widestNumberClass(Number... numbers)

Returns the smallest class that can hold all of the specified numbers.

Parameters:

numbers - The list with numbers that all should fit in the Number container.

Returns:

The Number container that is just large enough for all specified numbers.

isPackage

public static boolean isPackage(String name)

Validates whether a string represents a valid package.

Parameters:

name - The string representing a list of packages.

Returns:

A boolean indicating whether name represents a valid package.

containsAnnotation

public static boolean containsAnnotation(List<Annotation> myListOfAnnotations,
                                         Class<? extends Annotation> annotationClass)

Returns:

Whether a given list of Annotation contains a certain annotation type.

See Also:

findAnnotation(Collection, Class)

containsAnnotation

public static boolean containsAnnotation(Annotation[] myListOfAnnotations,
                                         Class<? extends Annotation> annotationClass)

Returns:

Whether a given list of Annotation contains a certain annotation type.

See Also:

findAnnotation(Annotation[], Class)

findAnnotation

@Nullable
public static <T extends Annotation> T findAnnotation(Collection<Annotation> myListOfAnnotations,
                                                                Class<T> annotationClass)

Returns:

Whether a given list of Annotation contains a certain annotation type.

See Also:

findAnnotation(Annotation[], Class)

findAnnotation

@Nullable
public static <T extends Annotation> T findAnnotation(Annotation[] myListOfAnnotations,
                                                                Class<T> annotationClass)

Returns:

Whether a given list of Annotation contains a certain annotation type.