Top Description Fields Constructors Methods
org.graalvm.polyglot

public abstract Class TypeLiteral<T>

extends Object
Class Inheritance
Imports
java.lang.reflect.Array, .GenericArrayType, .ParameterizedType, .Type
Represents a generic type T. Java doesn't yet provide a way to represent generic types, so this class does. Forces clients to create a subclass of this class which enables retrieval of the type information even at runtime.

For example, to create a type literal for List<String>, you can create an empty anonymous inner class:

TypeLiteral<List<String>> list = new TypeLiteral<List<String>>() {};

Since
19.0
See Also
org.graalvm.polyglot.Value#as(TypeLiteral)

Field Summary

Modifier and TypeField and Description
private final Class<T>
rawType

private final Type
type

Constructor Summary

AccessConstructor and Description
protected
TypeLiteral()

Constructs a new type literal.

Method Summary

Modifier and TypeMethod and Description
private static Class<?>
arrayTypeFromComponentType(Class<?> componentType)

public final boolean
equals(Object
the reference object with which to compare.
obj)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

private static Type
extractLiteralType(Class<? extends TypeLiteral<T>> literalClass)

private static Class<?>
extractRawType(Type type)

public final Class<T>
getRawType()

Returns the raw class type of the literal.

public final Type
getType()

Returns the type literal including generic type information.

public final int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public final String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

rawTypeback to summary
private final Class<T> rawType
typeback to summary
private final Type type

Constructor Detail

TypeLiteralback to summary
protected TypeLiteral()

Constructs a new type literal. Derives represented class from type parameter.

Clients create an empty anonymous subclass. Doing so embeds the type parameter in the anonymous class's type hierarchy so we can reconstitute it at runtime despite erasure.

Annotations
@SuppressWarnings:unchecked
Since
19.0

Method Detail

arrayTypeFromComponentTypeback to summary
private static Class<?> arrayTypeFromComponentType(Class<?> componentType)
equalsback to summary
public final boolean equals(Object obj)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
obj:Object

the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations
@Override
Since
19.0
extractLiteralTypeback to summary
private static Type extractLiteralType(Class<? extends TypeLiteral<T>> literalClass)
extractRawTypeback to summary
private static Class<?> extractRawType(Type type)
getRawTypeback to summary
public final Class<T> getRawType()

Returns the raw class type of the literal.

Since
19.0
getTypeback to summary
public final Type getType()

Returns the type literal including generic type information.

Since
19.0
hashCodeback to summary
public final int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object

Annotations
@Override
Since
19.0
toStringback to summary
public final String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override
Since
19.0