Module org.github.gestalt.core

Package org.github.gestalt.config.utils

Class ClassUtils

java.lang.Object

org.github.gestalt.config.utils.ClassUtils

public final class ClassUtils
extends java.lang.Object

Operates on classes without using reflection.

This class handles invalid null inputs as best it can. Each method documents its behavior in more detail.

The notion of a canonical name includes the human readable name for the type, for example int[]. The non-canonical method variants work with the JVM names, such as [I.

Since:

2.0

Method Summary

Modifier and Type	Method	Description
static boolean	isAssignable(java.lang.Class<?> cls, java.lang.Class<?> toClass)	Checks if one Class can be assigned to a variable of another Class.
static boolean	isAssignable(java.lang.Class<?> cls, java.lang.Class<?> toClass, boolean autoboxing)	Checks if one Class can be assigned to a variable of another Class.
static boolean	isPrimitiveOrWrapper(java.lang.Class<?> type)	Returns whether the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).
static boolean	isPrimitiveWrapper(java.lang.Class<?> type)	Returns whether the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).
static java.lang.Class<?>	primitiveToWrapper(java.lang.Class<?> cls)	Converts the specified primitive Class object to its corresponding wrapper Class object.
static java.lang.Class<?>	wrapperToPrimitive(java.lang.Class<?> cls)	Converts the specified wrapper class to its corresponding primitive class.

Methods inherited from class java.lang.Object

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

Method Detail

isAssignable

public static boolean isAssignable(java.lang.Class<?> cls,
                                   java.lang.Class<?> toClass)

Checks if one Class can be assigned to a variable of another Class.

Unlike the Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this Class object via an identity conversion widening primitive or widening reference conversion. See The Java Language Specification, sections 5.1.1, 5.1.2 and 5.1.4 for details.

Since Lang 3.0, this method will default behavior for calculating assignability between primitive and wrapper types corresponding to the running Java version; i.e. autoboxing will be the default behavior in VMs running Java versions > 1.5.

Parameters:

cls - the Class to check, may be null

toClass - the Class to try to assign into, returns false if null

Returns:

true if assignment possible

isAssignable

public static boolean isAssignable(java.lang.Class<?> cls,
                                   java.lang.Class<?> toClass,
                                   boolean autoboxing)

Checks if one Class can be assigned to a variable of another Class.

Unlike the Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this Class object via an identity conversion widening primitive or widening reference conversion. See The Java Language Specification, sections 5.1.1, 5.1.2 and 5.1.4 for details.

Parameters:

cls - the Class to check, may be null

toClass - the Class to try to assign into, returns false if null

autoboxing - whether to use implicit autoboxing/unboxing between primitives and wrappers

Returns:

true if assignment possible

primitiveToWrapper

public static java.lang.Class<?> primitiveToWrapper(java.lang.Class<?> cls)

Converts the specified primitive Class object to its corresponding wrapper Class object.

NOTE: From v2.2, this method handles Void.TYPE, returning Void.TYPE.

Parameters:

cls - the class to convert, may be null

Returns:

the wrapper class for cls or cls if cls is not a primitive. null if null input.

Since:

2.1

wrapperToPrimitive

public static java.lang.Class<?> wrapperToPrimitive(java.lang.Class<?> cls)

Converts the specified wrapper class to its corresponding primitive class.

This method is the counter part of primitiveToWrapper(). If the passed in class is a wrapper class for a primitive type, this primitive type will be returned (e.g. Integer.TYPE for Integer.class). For other classes, or if the parameter is null, the return value is null.

Parameters:

cls - the class to convert, may be null

Returns:

the corresponding primitive type if cls is a wrapper class, null otherwise

Since:

2.4

See Also:

primitiveToWrapper(Class)

isPrimitiveOrWrapper

public static boolean isPrimitiveOrWrapper(java.lang.Class<?> type)

Returns whether the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Parameters:

type - The class to query or null.

Returns:

true if the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Since:

3.1

isPrimitiveWrapper

public static boolean isPrimitiveWrapper(java.lang.Class<?> type)

Returns whether the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Parameters:

type - The class to query or null.

Returns:

true if the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Since:

3.1