Class TypeUtilities

java.lang.Object

jdk.dynalink.linker.support.TypeUtilities

public final class TypeUtilities
extends Object

Various static utility methods for working with Java types.

Since:

9

Method Summary

Modifier and Type	Method	Description
static Class<?>	getPrimitiveType(Class<?> wrapperType)	When passed a class representing a wrapper for a primitive type, returns the class representing the corresponding primitive type.
static Class<?>	getPrimitiveTypeByName(String name)	Given a name of a primitive type returns the class representing it.
static Class<?>	getWrapperType(Class<?> primitiveType)	When passed a class representing a primitive type, returns the class representing the corresponding wrapper type.
static boolean	isConvertibleWithoutLoss(Class<?> sourceType, Class<?> targetType)	Determines whether a type can be converted to another without losing any precision.
static boolean	isMethodInvocationConvertible(Class<?> sourceType, Class<?> targetType)	Determines whether one type can be converted to another type using a method invocation conversion, as per JLS 5.3 "Method Invocation Conversion".
static boolean	isSubtype(Class<?> subType, Class<?> superType)	Determines whether one type is a subtype of another type, as per JLS 4.10 "Subtyping".
static boolean	isWrapperType(Class<?> type)	Returns true if the passed type is a wrapper for a primitive type.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Method Details

isMethodInvocationConvertible

public static boolean isMethodInvocationConvertible(Class<?> sourceType,
 Class<?> targetType)

Determines whether one type can be converted to another type using a method invocation conversion, as per JLS 5.3 "Method Invocation Conversion". This is basically all conversions allowed by subtyping (see isSubtype(Class, Class)) as well as boxing conversion (JLS 5.1.7) optionally followed by widening reference conversion, and unboxing conversion (JLS 5.1.8) optionally followed by widening primitive conversion.

Parameters:

sourceType - the type being converted from (call site type for parameter types, method type for return types)

targetType - the parameter type being converted to (method type for parameter types, call site type for return types)

Returns:

true if source type is method invocation convertible to target type.

isConvertibleWithoutLoss

public static boolean isConvertibleWithoutLoss(Class<?> sourceType,
 Class<?> targetType)

Determines whether a type can be converted to another without losing any precision. As a special case, void is considered convertible only to void and Object (either as null or as a custom value set in DynamicLinkerFactory.setAutoConversionStrategy(MethodTypeConversionStrategy)). Somewhat unintuitively, we consider anything to be convertible to void even though converting to void causes the ultimate loss of data. On the other hand, conversion to void essentially means that the value is of no interest and should be discarded, thus there's no expectation of preserving any precision.

Parameters:

sourceType - the source type

targetType - the target type

Returns:

true if lossless conversion is possible

isSubtype

public static boolean isSubtype(Class<?> subType,
 Class<?> superType)

Determines whether one type is a subtype of another type, as per JLS 4.10 "Subtyping". Note: this is not strict or proper subtype, therefore true is also returned for identical types; to be completely precise, it allows identity conversion (JLS 5.1.1), widening primitive conversion (JLS 5.1.2) and widening reference conversion (JLS 5.1.5).

Parameters:

subType - the supposed subtype

superType - the supposed supertype of the subtype

Returns:

true if subType can be converted by identity conversion, widening primitive conversion, or widening reference conversion to superType.

getPrimitiveTypeByName

public static Class<?> getPrimitiveTypeByName(String name)

Given a name of a primitive type returns the class representing it. I.e. when invoked with "int", returns Integer.TYPE.

Parameters:

name - the name of the primitive type

Returns:

the class representing the primitive type, or null if the name does not correspond to a primitive type.

getPrimitiveType

public static Class<?> getPrimitiveType(Class<?> wrapperType)

When passed a class representing a wrapper for a primitive type, returns the class representing the corresponding primitive type. I.e. calling it with Integer.class will return Integer.TYPE. If passed a class that is not a wrapper for primitive type, returns null.

Parameters:

wrapperType - the class object representing a wrapper for a primitive type.

Returns:

the class object representing the primitive type, or null if the passed class is not a primitive wrapper.

getWrapperType

public static Class<?> getWrapperType(Class<?> primitiveType)

When passed a class representing a primitive type, returns the class representing the corresponding wrapper type. I.e. calling it with int.class will return Integer.class. If passed a class that is not a primitive type, returns null.

Parameters:

primitiveType - the class object representing a primitive type

Returns:

the class object representing the wrapper type, or null if the passed class is not a primitive.

isWrapperType

public static boolean isWrapperType(Class<?> type)

Returns true if the passed type is a wrapper for a primitive type.

Parameters:

type - the examined type

Returns:

true if the passed type is a wrapper for a primitive type.