TypeDescriptor (GraalVM Truffle Java API Reference)

java.lang.Object
- org.graalvm.polyglot.tck.TypeDescriptor

```
public final class TypeDescriptor
extends Object
```
Represents a type of a polyglot value. Types include primitive types, null type, object type, array type with an optional content type and union type.

Since:

0.30

Field Summary

Fields
Modifier and Type	Field and Description
`static TypeDescriptor`	`ANY` Represents all types.
`static TypeDescriptor`	`ARRAY` Represents an array with any content type.
`static TypeDescriptor`	`BOOLEAN` Represents a boolean type.
`static TypeDescriptor`	`DATE` Type descriptor for date.
`static TypeDescriptor`	`DURATION` Type descriptor for duration.
`static TypeDescriptor`	`EXCEPTION` Type descriptor for exception.
`static TypeDescriptor`	`EXECUTABLE` Represents an executable type returning any type and accepting any number of parameters of any type.
`static TypeDescriptor`	`EXECUTABLE_ANY` Represents a raw executable type.
`static TypeDescriptor`	`HASH` Represents a hash map with any key type and any value type.
`static TypeDescriptor`	`HOST_OBJECT` Represents a host object.
`static TypeDescriptor`	`INSTANTIABLE` Represents an instantiable type accepting any number of parameters of any type.
`static TypeDescriptor`	`INSTANTIABLE_ANY` Represents a raw instantiable type.
`static TypeDescriptor`	`ITERABLE` Represents an iterable with any content type.
`static TypeDescriptor`	`ITERATOR` Represents an iterator with any content type.
`static TypeDescriptor`	`META_OBJECT` Type descriptor for metaobjects.
`static TypeDescriptor`	`NATIVE_POINTER` Represents a native pointer.
`static TypeDescriptor`	`NULL` The NULL type represents a type of null or undefined value.
`static TypeDescriptor`	`NUMBER` Represents a numeric type.
`static TypeDescriptor`	`OBJECT` Represents an object created by a guest language.
`static TypeDescriptor`	`STRING` Represents a string type.
`static TypeDescriptor`	`TIME` Type descriptor for time.
`static TypeDescriptor`	`TIME_ZONE` Type descriptor for time zone.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static TypeDescriptor`	`array(TypeDescriptor componentType)` Creates a new array type with given component type.
`boolean`	`equals(Object obj)`
`static TypeDescriptor`	`executable(TypeDescriptor returnType, boolean vararg, TypeDescriptor... parameterTypes)` Creates a new executable type with a given return type and parameter types.
`static TypeDescriptor`	`executable(TypeDescriptor returnType, TypeDescriptor... parameterTypes)` Creates a new executable type with a given return type and parameter types.
`static TypeDescriptor`	`forValue(Value value)` Creates a type for given `Value`.
`static TypeDescriptor`	`hash(TypeDescriptor keyType, TypeDescriptor valueType)` Creates a new hash map type with given key type and value type.
`int`	`hashCode()`
`static TypeDescriptor`	`instantiable(TypeDescriptor instanceType, boolean vararg, TypeDescriptor... parameterTypes)` Creates a new instantiable type with a given parameter types.
`static TypeDescriptor`	`intersection(TypeDescriptor... types)` Creates a new intersection type.
`boolean`	`isAssignable(TypeDescriptor fromType)` Checks if the given type is assignable to this type.
`boolean`	`isIntersection()` Checks if this `TypeDescriptor` represent an intersection type.
`boolean`	`isUnion()` Checks if this `TypeDescriptor` represent an union type.
`static TypeDescriptor`	`iterable(TypeDescriptor componentType)` Creates a new iterable type with given component type.
`static TypeDescriptor`	`iterator(TypeDescriptor componentType)` Creates a new iterator type with given component type.
`TypeDescriptor`	`subtract(TypeDescriptor toRemove)` Creates a new type by removing the given type from this type.
`String`	`toString()`
`static TypeDescriptor`	`union(TypeDescriptor... types)` Creates a new union type.

Methods inherited from class java.lang.Object
clone, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - NULL
```
public static final TypeDescriptor NULL
```
    The NULL type represents a type of null or undefined value.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isNull().
  - BOOLEAN
```
public static final TypeDescriptor BOOLEAN
```
    Represents a boolean type.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isBoolean().
  - NUMBER
```
public static final TypeDescriptor NUMBER
```
    Represents a numeric type.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isNumber().
  - STRING
```
public static final TypeDescriptor STRING
```
    Represents a string type.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isString().
  - ITERABLE
```
public static final TypeDescriptor ITERABLE
```
    Represents an iterable with any content type. Any iterable type, including those with content type, is assignable to this type. This iterable type is not assignable to any iterable type having a content type.
    
    Since:
    
    21.1
    
    See Also:
    
    TypeDescriptor.isAssignable(org.graalvm.polyglot.tck.TypeDescriptor)., TypeDescriptor.iterable(TypeDescriptor)., Value.hasIterator().
  - ITERATOR
```
public static final TypeDescriptor ITERATOR
```
    Represents an iterator with any content type. Any iterator type, including those with content type, is assignable to this type. This iterator type is not assignable to any iterator type having a content type.
    
    Since:
    
    21.1
    
    See Also:
    
    TypeDescriptor.isAssignable(org.graalvm.polyglot.tck.TypeDescriptor)., TypeDescriptor.iterator(TypeDescriptor)., Value.isIterator().
  - HASH
```
public static final TypeDescriptor HASH
```
    Represents a hash map with any key type and any value type. Any hash map type, including those with specified key and value types, is assignable to this type. This hash map type is not assignable to any hash map type with specified key or value types.
    
    Since:
    
    21.1
    
    See Also:
    
    TypeDescriptor.isAssignable(org.graalvm.polyglot.tck.TypeDescriptor)., TypeDescriptor.hash(TypeDescriptor, TypeDescriptor)., Value.hasHashEntries()
  - OBJECT
```
public static final TypeDescriptor OBJECT
```
    Represents an object created by a guest language.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.hasMembers().
  - ARRAY
```
public static final TypeDescriptor ARRAY
```
    Represents an array with any content type. Any array type, including those with content type, is assignable to this type. This array type is not assignable to any array type having a content type.
    
    Since:
    
    0.30
    
    See Also:
    
    TypeDescriptor.isAssignable(org.graalvm.polyglot.tck.TypeDescriptor)., Value.hasArrayElements().
  - HOST_OBJECT
```
public static final TypeDescriptor HOST_OBJECT
```
    Represents a host object.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isHostObject().
  - NATIVE_POINTER
```
public static final TypeDescriptor NATIVE_POINTER
```
    Represents a native pointer.
    
    Since:
    
    0.30
    
    See Also:
    
    Value.isNativePointer().
  - DATE
```
public static final TypeDescriptor DATE
```
    Type descriptor for date.
    
    Since:
    
    20.0
    
    See Also:
    
    Value.isDate().
  - TIME
```
public static final TypeDescriptor TIME
```
    Type descriptor for time.
    
    Since:
    
    20.0
    
    See Also:
    
    Value.isTime().
  - TIME_ZONE
```
public static final TypeDescriptor TIME_ZONE
```
    Type descriptor for time zone.
    
    Since:
    
    20.0
    
    See Also:
    
    Value.isTimeZone().
  - DURATION
```
public static final TypeDescriptor DURATION
```
    Type descriptor for duration.
    
    Since:
    
    20.0
    
    See Also:
    
    Value.isDuration().
  - META_OBJECT
```
public static final TypeDescriptor META_OBJECT
```
    Type descriptor for metaobjects.
    
    Since:
    
    20.0
    
    See Also:
    
    Value.isMetaObject().
  - EXCEPTION
```
public static final TypeDescriptor EXCEPTION
```
    Type descriptor for exception.
    
    Since:
    
    19.3
    
    See Also:
    
    Value.isException()
  - EXECUTABLE
```
public static final TypeDescriptor EXECUTABLE
```
    Represents an executable type returning any type and accepting any number of parameters of any type. To create an executable type with concrete types use TypeDescriptor.executable(org.graalvm.polyglot.tck.TypeDescriptor, org.graalvm.polyglot.tck.TypeDescriptor...) . This type can be used for creating value constructors but should not be used for specifying expressions or statements parameter types as no other executable is assignable to it.
    The JavaScript sample usage for no argument function constructor:
```
@Override
public Collection<? extends Snippet> createValueConstructors(Context context) {
    return Collections.singleton(Snippet.newBuilder(
            "function",
            context.eval("js", "(function(){ return function(){}})"),
            TypeDescriptor.EXECUTABLE).build());
}
```
    Since:
    
    0.30
    
    See Also:
    
    Value.canExecute().
  - EXECUTABLE_ANY
```
public static final TypeDescriptor EXECUTABLE_ANY
```
    Represents a raw executable type. Any executable can be assigned into the raw executable type, but the raw executable type cannot be assigned to any other executable. To create an executable type with concrete types use TypeDescriptor.executable(org.graalvm.polyglot.tck.TypeDescriptor, org.graalvm.polyglot.tck.TypeDescriptor...) . This type can be used for specifying expressions or statements parameter types when the passed executable is actually not invoked.
    The JavaScript sample usage for plus operator:
```
@Override
public Collection<? extends Snippet> createExpressions(Context context) {
    final Collection<Snippet> expressions = new ArrayList<>();
    final TypeDescriptor numeric = TypeDescriptor.union(
            TypeDescriptor.NUMBER,
            TypeDescriptor.BOOLEAN);
    final TypeDescriptor nonNumeric = TypeDescriptor.union(
            TypeDescriptor.STRING,
            TypeDescriptor.OBJECT,
            TypeDescriptor.ARRAY,
            TypeDescriptor.EXECUTABLE_ANY);
    Snippet.Builder builder = Snippet.newBuilder(
            "+",
            context.eval(
                    "js",
                    "(function (a, b){ return a + b;})"),
            TypeDescriptor.NUMBER).
        parameterTypes(numeric, numeric);
    expressions.add(builder.build());
    builder = Snippet.newBuilder(
            "+",
            context.eval(
                    "js",
                    "(function (a, b){ return a + b;})"),
            TypeDescriptor.STRING).
        parameterTypes(nonNumeric, TypeDescriptor.ANY);
    expressions.add(builder.build());
    builder = Snippet.newBuilder(
            "+",
            context.eval(
                    "js",
                    "(function (a, b){ return a + b;})"),
            TypeDescriptor.STRING).
        parameterTypes(TypeDescriptor.ANY, nonNumeric);
    expressions.add(builder.build());
    return expressions;
}
```
    Since:
    
    19.0
    
    See Also:
    
    TypeDescriptor.EXECUTABLE
  - INSTANTIABLE
```
public static final TypeDescriptor INSTANTIABLE
```
    Represents an instantiable type accepting any number of parameters of any type. To create an instantiable type with concrete parameter types use TypeDescriptor.instantiable(org.graalvm.polyglot.tck.TypeDescriptor, boolean, org.graalvm.polyglot.tck.TypeDescriptor...) . This type can be used for creating value constructors but should not be used for specifying expressions or statements parameter types as no other instantiable is assignable to it.
    
    Since:
    
    19.0
    
    See Also:
    
    Value.canInstantiate().
  - INSTANTIABLE_ANY
```
public static final TypeDescriptor INSTANTIABLE_ANY
```
    Represents a raw instantiable type. Any instantiable can be assigned into this raw instantiable type, but the raw instantiable type cannot be assigned to any other instantiable. To create an instantiable type with concrete types use TypeDescriptor.instantiable(org.graalvm.polyglot.tck.TypeDescriptor, boolean, org.graalvm.polyglot.tck.TypeDescriptor...) . This type can be used for specifying expressions or statements parameter types when the passed instantiable is actually not invoked.
    
    Since:
    
    19.0
    
    See Also:
    
    TypeDescriptor.INSTANTIABLE
  - ANY
```
public static final TypeDescriptor ANY
```
    Represents all types. It's an intersection of no type.
    
    Since:
    
    0.30
- Method Detail
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
    
    Since:
    
    0.30
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
    
    Since:
    
    0.30
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
    
    Since:
    
    0.30
  - isAssignable
```
public boolean isAssignable(TypeDescriptor fromType)
```
    Checks if the given type is assignable to this type. The primitive types are assignable only to itself or to an union type containing the given primitive type. The array type with a component type can be assigned to itself, to an array type without a component type and to an union type containing the given array type or an array type without a component type. The union type can be assigned to other union type containing all union elements. The intersection type can be assigned to type having any intersection type. To the target intersection type only an intersection type having all the target intersection elements can be assigned.
    
    Parameters:
    
    fromType - the type to assign
    
    Returns:
    
    true if the fromType is assignable to this type
    
    Since:
    
    0.30
  - isUnion
```
public boolean isUnion()
```
    Checks if this TypeDescriptor represent an union type.
    
    Returns:
    
    true if this type represents an union type
    
    Since:
    
    0.30
  - isIntersection
```
public boolean isIntersection()
```
    Checks if this TypeDescriptor represent an intersection type.
    
    Returns:
    
    true if this type represents an intersection type
    
    Since:
    
    0.30
  - union
```
public static TypeDescriptor union(TypeDescriptor... types)
```
    Creates a new union type. The union type is any of the given types.
    
    Parameters:
    
    types - the types to include in the union
    
    Returns:
    
    the union type containing the given types
    
    Since:
    
    0.30
  - intersection
```
public static TypeDescriptor intersection(TypeDescriptor... types)
```
    Creates a new intersection type. The intersection type is all of the given types. The intersection can be also used to create a no type. The no type is a type which has no other specialized type. The no type can be assigned to TypeDescriptor.ANY and itself. The no type is created as an empty intersection, TypeDescriptor.intersection().
    
    Parameters:
    
    types - the types to include in the intersection
    
    Returns:
    
    the intersection type containing the given types
    
    Since:
    
    0.30
  - subtract
```
public TypeDescriptor subtract(TypeDescriptor toRemove)
```
    Creates a new type by removing the given type from this type. The type subtraction works in the following way:
    - If this type and the toRemove type represent the same types then no type is returned.
    - If this type represents a union type the toRemove type is removed from the union type. When the toRemove type is also a union type then all types in the toRemove union type are removed.
    - If this type represents an intersection type the toRemove type is removed from the intersection type. When the toRemove type is also an intersection type then all types in the toRemove intersection type are removed.
    - If this and toRemove types are parameterized types (array, iterable, iterator, hash) of the same kind the type parameter types are subtracted applying the same rules.
    Examples:
    - NUMBER.subtract(NUMBER) -> no type
    - NUMBER.subtract(STRING) -> NUMBER
    - UNION[NUMBER|STRING|OBJECT].subtract(NUMBER) -> UNION[STRING|OBJECT]
    - UNION[NUMBER|STRING|OBJECT].subtract(UNION[NUMBER|STRING]) -> OBJECT
    - INTERSECTION[NUMBER&STRING&OBJECT].subtract(NUMBER) -> INTERSECTION[STRING&OBJECT]
    - INTERSECTION[NUMBER&STRING&OBJECT].subtract(INTERSECTION[NUMBER&STRING]) -> OBJECT
    - ARRAY[UNION[NUMBER|STRING]].subtract(ARRAY[NUMBER]) -> ARRAY[STRING]
    - ARRAY[INTERSECTION[NUMBER|STRING]].subtract(ARRAY[NUMBER]) -> ARRAY[STRING]
    Parameters:
    
    toRemove - the type to remove.
    
    Since:
    
    20.2
  - array
```
public static TypeDescriptor array(TypeDescriptor componentType)
```
    Creates a new array type with given component type. To create a multi-dimensional array use an array type as a component type.
    
    Parameters:
    
    componentType - the required component type.
    
    Returns:
    
    an array type with given component
    
    Since:
    
    0.30
  - iterable
```
public static TypeDescriptor iterable(TypeDescriptor componentType)
```
    Creates a new iterable type with given component type.
    
    Parameters:
    
    componentType - the required component type.
    
    Returns:
    
    an iterable type with given component
    
    Since:
    
    21.1
  - iterator
```
public static TypeDescriptor iterator(TypeDescriptor componentType)
```
    Creates a new iterator type with given component type.
    
    Parameters:
    
    componentType - the required component type.
    
    Returns:
    
    an iterator type with given component
    
    Since:
    
    21.1
  - hash
```
public static TypeDescriptor hash(TypeDescriptor keyType,
                                  TypeDescriptor valueType)
```
    Creates a new hash map type with given key type and value type.
    
    Parameters:
    
    keyType - the required key type.
    
    valueType - the required value type.
    
    Returns:
    
    a new hash map type with given key and value types
    
    Since:
    
    21.1
  - executable
```
public static TypeDescriptor executable(TypeDescriptor returnType,
                                        TypeDescriptor... parameterTypes)
```
    Creates a new executable type with a given return type and parameter types.
    
    Parameters:
    
    returnType - the required return type, use ANY as any type
    
    parameterTypes - the required parameter types
    
    Returns:
    
    an executable type
    
    Since:
    
    0.30
  - executable
```
public static TypeDescriptor executable(TypeDescriptor returnType,
                                        boolean vararg,
                                        TypeDescriptor... parameterTypes)
```
    Creates a new executable type with a given return type and parameter types.
    
    Parameters:
    
    returnType - the required return type, use ANY as any type
    
    vararg - the executable has variable length arguments or ignores additional parameters. For executables created by the LanguageProvider.createValueConstructors(org.graalvm.polyglot.Context) set to false if the language neither ignores extra parameters nor the executable has variable arguments length.
    
    parameterTypes - the required parameter types
    
    Returns:
    
    an executable type
    
    Since:
    
    0.31
  - instantiable
```
public static TypeDescriptor instantiable(TypeDescriptor instanceType,
                                          boolean vararg,
                                          TypeDescriptor... parameterTypes)
```
    Creates a new instantiable type with a given parameter types.
    
    Parameters:
    
    instanceType - the type of an instance, use ANY as any type
    
    vararg - the instantiable has variable length arguments or ignores additional parameters. For instantiables created by the LanguageProvider.createValueConstructors(org.graalvm.polyglot.Context) set to false if the language neither ignores extra parameters nor the instantiable has variable arguments length.
    
    parameterTypes - the required parameter types
    
    Returns:
    
    an instantiable type
    
    Since:
    
    19.0
  - forValue
```
public static TypeDescriptor forValue(Value value)
```
    Creates a type for given Value.
    
    Parameters:
    
    value - the value to create TypeDescriptor for
    
    Returns:
    
    the type of value, may by an union type containing more primitive or array types.
    
    Since:
    
    0.30

Class TypeDescriptor

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NULL

BOOLEAN

NUMBER

STRING

ITERABLE

ITERATOR

HASH

OBJECT

ARRAY

HOST_OBJECT

NATIVE_POINTER

DATE

TIME

TIME_ZONE

DURATION

META_OBJECT

EXCEPTION

EXECUTABLE

EXECUTABLE_ANY

INSTANTIABLE

INSTANTIABLE_ANY

ANY

Method Detail

hashCode

equals

toString

isAssignable

isUnion

isIntersection

union

intersection

subtract

array

iterable

iterator

hash

executable

executable

instantiable

forValue