blue.endless.jankson.magic

Class TypeMagic

java.lang.Object

blue.endless.jankson.magic.TypeMagic

public class TypeMagic
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
TypeMagic()

Method Summary

Modifier and Type	Method and Description
static java.lang.Class<?>	classForType(java.lang.reflect.Type t) This is a surprisingly intractable problem in Java: "Type" pretty much represents all possible states of reified and unreified type information, and each kind of Type has different, mutually exclusive, and often unintended ways of uncovering its (un-reified) class.
static <U> U	createAndCast(java.lang.Class<U> t, boolean failFast) Attempts to create a new instance of the specified class using its no-arg constructor, if it has one.
static <U> U	createAndCast(java.lang.reflect.Type t) Attempts to create a new instance of type t, and (unsafely) cast it to the target type U.
static <U> U	createAndCastCarefully(java.lang.reflect.Type t)
static <T> T	shoehorn(java.lang.Object o) Extremely unsafely casts an object into another type.

Methods inherited from class java.lang.Object

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

Constructor Detail

TypeMagic

public TypeMagic()

Method Detail

classForType

@Nullable
public static java.lang.Class<?> classForType(java.lang.reflect.Type t)

This is a surprisingly intractable problem in Java: "Type" pretty much represents all possible states of reified and unreified type information, and each kind of Type has different, mutually exclusive, and often unintended ways of uncovering its (un-reified) class.

Generally it's much safer to use this for the type from a *field* than a blind type from an argument.

createAndCast

@Nullable
public static <U> U createAndCast(java.lang.reflect.Type t)

Attempts to create a new instance of type t, and (unsafely) cast it to the target type U. This might work even if the class is private or has a private constructor.

Type Parameters:

U - the target type.

Parameters:

t - the source type. The object will be created as this type.

Returns:

an object of type t, cast to type U. If any part of this process fails, this method silently returns null instead.

createAndCastCarefully

public static <U> U createAndCastCarefully(java.lang.reflect.Type t)
                                    throws DeserializationException

Throws:

DeserializationException

createAndCast

@Nullable
public static <U> U createAndCast(java.lang.Class<U> t,
                                            boolean failFast)
                                     throws DeserializationException

Attempts to create a new instance of the specified class using its no-arg constructor, if it has one. This might work even if the class is private or the constructor is private/hidden!

Type Parameters:

U - the target type.

Parameters:

t - the source type. The object will be created as this type.

Returns:

a new object of type U. If any part of this process fails, this method silently returns null instead.

Throws:

DeserializationException

shoehorn

public static <T> T shoehorn(java.lang.Object o)

Extremely unsafely casts an object into another type. It's possible to mangle a List<Integer> into a List<String> this way, and the JVM might not throw an error until the program attempts to insert a String! So use this method with extreme caution as a last resort.

Type Parameters:

T - the destination type

Parameters:

o - the source object, of any type

Returns:

the source object cast to T.