TypeMirror abstract

abstract class TypeMirror implements DeclarationMirror

A TypeMirror reflects a Dart language class, typedef, function type or type variable.

Implemented types

• DeclarationMirror

Implementers

• ClassMirror
• TypedefMirror
• TypeVariableMirror

Constructors

TypeMirror()

TypeMirror()

Properties

hashCode no setter inherited

int get hashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Inherited from Object.

Implementation

external int get hashCode;

hasReflectedType no setter

bool get hasReflectedType

Returns true if this mirror reflects dynamic, a non-generic class or typedef, or an instantiated generic class or typedef in the current isolate. Otherwise, returns false.

Implementation

bool get hasReflectedType;

isOriginalDeclaration no setter

bool get isOriginalDeclaration

Is this the original declaration of this type?

For most classes, they are their own original declaration. For generic classes, however, there is a distinction between the original class declaration, which has unbound type variables, and the instantiations of generic classes, which have bound type variables.

Implementation

bool get isOriginalDeclaration;

isPrivate no setter inherited

bool get isPrivate

Whether this declaration is library private.

Always returns false for a library declaration, otherwise returns true if the declaration's name starts with an underscore character (_), and false if it doesn't.

Inherited from DeclarationMirror.

Implementation

bool get isPrivate;

isTopLevel no setter inherited

bool get isTopLevel

Whether this declaration is top-level.

A declaration is considered top-level if its owner is a LibraryMirror.

Inherited from DeclarationMirror.

Implementation

bool get isTopLevel;

location no setter inherited

SourceLocation? get location

The source location of this Dart language entity, or null if the entity is synthetic.

If the reflectee is a variable, the returned location gives the position of the variable name at its point of declaration.

If the reflectee is a library, class, typedef, function or type variable with associated metadata, the returned location gives the position of the first metadata declaration associated with the reflectee.

Otherwise:

If the reflectee is a library, the returned location gives the position of the keyword 'library' at the reflectee's point of declaration, if the reflectee is a named library, or the first character of the first line in the compilation unit defining the reflectee if the reflectee is anonymous.

If the reflectee is an abstract class, the returned location gives the position of the keyword 'abstract' at the reflectee's point of declaration. Otherwise, if the reflectee is a class, the returned location gives the position of the keyword 'class' at the reflectee's point of declaration.

If the reflectee is a typedef the returned location gives the position of the of the keyword 'typedef' at the reflectee's point of declaration.

If the reflectee is a function with a declared return type, the returned location gives the position of the function's return type at the reflectee's point of declaration. Otherwise. the returned location gives the position of the function's name at the reflectee's point of declaration.

This operation is optional and may throw an UnsupportedError.

Inherited from DeclarationMirror.

Implementation

SourceLocation? get location;

metadata no setter inherited

List<InstanceMirror> get metadata

A list of the metadata associated with this declaration.

Let D be the declaration this mirror reflects. If D is decorated with annotations A1, ..., An where n > 0, then for each annotation Ai associated with D, 1 <= i <= n, let ci be the constant object specified by Ai. Then this method returns a list whose members are instance mirrors on c1, ..., cn. If no annotations are associated with D, then an empty list is returned.

If evaluating any of c1, ..., cn would cause a compilation error the effect is the same as if a non-reflective compilation error had been encountered.

Inherited from DeclarationMirror.

Implementation

List<InstanceMirror> get metadata;

originalDeclaration no setter

TypeMirror get originalDeclaration

A mirror on the original declaration of this type.

For most classes, they are their own original declaration. For generic classes, however, there is a distinction between the original class declaration, which has unbound type variables, and the instantiations of generic classes, which have bound type variables.

Implementation

TypeMirror get originalDeclaration;

owner no setter inherited

DeclarationMirror? get owner

A mirror on the owner of this Dart language entity.

The owner is the declaration immediately surrounding the reflectee:

• For a library, the owner is null.
• For a class declaration, typedef or top level function or variable, the owner is the enclosing library.
• For a mixin application S with M, the owner is the owner of M.
• For a constructor, the owner is the immediately enclosing class.
• For a method, instance variable or a static variable, the owner is the immediately enclosing class, unless the class is a mixin application S with M, in which case the owner is M. Note that M may be an invocation of a generic.
• For a parameter, local variable or local function the owner is the immediately enclosing function.

Inherited from DeclarationMirror.

Implementation

DeclarationMirror? get owner;

qualifiedName no setter inherited

Symbol get qualifiedName

The fully-qualified name for this Dart language entity.

This name is qualified by the name of the owner. For instance, the qualified name of a method 'method' in class 'Class' in library 'library' is 'library.Class.method'.

Returns a Symbol constructed from a string representing the fully qualified name of the reflectee. Let o be the owner of this mirror, let r be the reflectee of this mirror, let p be the fully qualified name of the reflectee of o, and let s be the simple name of r computed by simpleName. The fully qualified name of r is the concatenation of p, '.', and s.

Because an isolate can contain more than one library with the same name (at different URIs), a fully-qualified name does not uniquely identify any language entity.

Inherited from DeclarationMirror.

Implementation

Symbol get qualifiedName;

reflectedType no setter

Type get reflectedType

If hasReflectedType returns true, returns the corresponding Type. Otherwise, an UnsupportedError is thrown.

Implementation

Type get reflectedType;

runtimeType no setter inherited

Type get runtimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

external Type get runtimeType;

simpleName no setter inherited

Symbol get simpleName

The simple name for this Dart language entity.

The simple name is in most cases the identifier name of the entity, such as 'myMethod' for a method, void myMethod() {...} or 'mylibrary' for a library 'mylibrary'; declaration.

Inherited from DeclarationMirror.

Implementation

Symbol get simpleName;

typeArguments no setter

List<TypeMirror> get typeArguments

An immutable list with mirrors for all type arguments for this type.

If the reflectee is an invocation of a generic class, the type arguments are the bindings of its type parameters. If the reflectee is the original declaration of a generic, it has no type arguments and this method returns an empty list. If the reflectee is not generic, then it has no type arguments and this method returns an empty list.

This list preserves the order of declaration of the type variables.

Implementation

List<TypeMirror> get typeArguments;

typeVariables no setter

List<TypeVariableMirror> get typeVariables

An immutable list with mirrors for all type variables for this type.

If this type is a generic declaration or an invocation of a generic declaration, the returned list contains mirrors on the type variables declared in the original declaration. Otherwise, the returned list is empty.

This list preserves the order of declaration of the type variables.

Implementation

List<TypeVariableMirror> get typeVariables;

Methods

isAssignableTo()

bool isAssignableTo(TypeMirror other)

Checks the assignability relationship, denoted by <=> in the language specification.

This is the type relationship tested on assignment in checked mode.

Implementation

bool isAssignableTo(TypeMirror other);

isSubtypeOf()

bool isSubtypeOf(TypeMirror other)

Checks the subtype relationship, denoted by <: in the language specification.

This is the type relationship used in is test checks.

Implementation

bool isSubtypeOf(TypeMirror other);

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Object.

Implementation

external String toString();

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Object.

Implementation

external bool operator ==(Object other);