com.google.javascript.rhino.jstype
Class NoType

java.lang.Object
  com.google.javascript.rhino.jstype.JSType
      com.google.javascript.rhino.jstype.ObjectType
          com.google.javascript.rhino.jstype.FunctionType
              com.google.javascript.rhino.jstype.NoObjectType
                  com.google.javascript.rhino.jstype.NoType

All Implemented Interfaces:

StaticScope<JSType>, Serializable

public class NoType
extends NoObjectType

Bottom type, representing the subclass of any value or object. Although JavaScript programmers can't explicitly denote the bottom type, it comes up in static analysis. For example, if we have: var x = null; if (x) { f(x); } We need to be able to assign x a type within the f(x) call. Since it has no possible type, we assign x the NoType, so that f(x) is legal no matter what the type of f's first argument is.

See Also:

Bottom types, Serialized Form

isNoObjectType

public boolean isNoObjectType()

Overrides:

isNoObjectType in class NoObjectType

isNoType

public boolean isNoType()

Overrides:

isNoType in class JSType

isNullable

public boolean isNullable()

Description copied from class: JSType

Tests whether this type is nullable.

Overrides:

isNullable in class JSType

isSubtype

public boolean isSubtype(JSType that)

Description copied from class: FunctionType

A function is a subtype of another if their call methods are related via subtyping and this is a subtype of that with regard to the prototype chain.

Overrides:

isSubtype in class NoObjectType

Returns:

this <: that

getPossibleToBooleanOutcomes

public BooleanLiteralSet getPossibleToBooleanOutcomes()

Description copied from class: JSType

Computes the set of possible outcomes of the ToBoolean predicate for this type. The ToBoolean predicate is defined by the ECMA-262 standard, 3^rd edition. Its behavior for simple types can be summarized by the following table:

type	result
undefined	{false}
null	{false}
boolean	{true, false}
number	{true, false}
string	{true, false}
Object	{true}

Overrides:

getPossibleToBooleanOutcomes in class ObjectType

Returns:

the set of boolean literals for this type

matchesNumberContext

public boolean matchesNumberContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in a numeric context, such as an operand of a multiply operator.

Overrides:

matchesNumberContext in class NoObjectType

matchesObjectContext

public boolean matchesObjectContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in an Object context, such as the expression in a with statement. Most types we will encounter, except notably null, have at least the potential for converting to Object. Host defined objects can get peculiar.

Overrides:

matchesObjectContext in class NoObjectType

matchesStringContext

public boolean matchesStringContext()

Description copied from class: JSType

This predicate is used to test whether a given type can appear in a String context, such as an operand of a string concat (+) operator. All types have at least the potential for converting to String. When we add externally defined types, such as a browser OM, we may choose to add types that do not automatically convert to String.

Overrides:

matchesStringContext in class NoObjectType

visit

public <T> T visit(Visitor<T> visitor)

Description copied from class: JSType

Visit this type with the given visitor.

Overrides:

visit in class NoObjectType

Returns:

the value returned by the visitor

See Also:

Visitor

hasOwnProperty

public boolean hasOwnProperty(String propertyName)

Description copied from class: ObjectType

Checks whether the property whose name is given is present directly on the object. Returns false even if it is declared on a supertype.

Overrides:

hasOwnProperty in class ObjectType

isPropertyTypeDeclared

public boolean isPropertyTypeDeclared(String property)

Description copied from class: ObjectType

Checks whether the property's type is declared.

Specified by:

isPropertyTypeDeclared in class ObjectType

isPropertyInExterns

public boolean isPropertyInExterns(String propertyName)

Description copied from class: ObjectType

Checks whether the property was defined in the externs.

Overrides:

isPropertyInExterns in class ObjectType

getPropertyNode

public Node getPropertyNode(String propertyName)

Description copied from class: ObjectType

Gets the node corresponding to the definition of the specified property. This could be the node corresponding to declaration of the property or the node corresponding to the first reference to this property, e.g., "this.propertyName" in a constructor. Note this is mainly intended to be an estimate of where in the source code a property is defined. Sometime the returned node is not even part of the global AST but in the AST of the JsDoc that defines a type.

Overrides:

getPropertyNode in class ObjectType

Parameters:

propertyName - the name of the property

Returns:

the Node corresponding to the property or null.

unboxesTo

public JSType unboxesTo()

Description copied from class: JSType

Gets the type to which this type unboxes.

Overrides:

unboxesTo in class JSType

Returns:

the unboxed type or null if this type does not unbox.

hasReferenceName

public boolean hasReferenceName()

Description copied from class: ObjectType

Returns true if the object is named.

Overrides:

hasReferenceName in class ObjectType

Returns:

true if the object is named, false if it is anonymous

isNativeObjectType

public boolean isNativeObjectType()

Whether this is a built-in object.

Overrides:

isNativeObjectType in class ObjectType

getOwnerFunction

public FunctionType getOwnerFunction()

Description copied from class: ObjectType

Gets the owner of this if it's a function prototype.

Overrides:

getOwnerFunction in class ObjectType

getCtorImplementedInterfaces

public Iterable<ObjectType> getCtorImplementedInterfaces()

Description copied from class: ObjectType

Gets the interfaces implemented by the ctor associated with this type. Intended to be overridden by subclasses.

Overrides:

getCtorImplementedInterfaces in class ObjectType

getCtorExtendedInterfaces

public Iterable<ObjectType> getCtorExtendedInterfaces()

Description copied from class: ObjectType

Gets the interfaces extended by the interface associated with this type. Intended to be overridden by subclasses.

Overrides:

getCtorExtendedInterfaces in class ObjectType

matchConstraint

public void matchConstraint(JSType constraint)

Description copied from class: JSType

Modify this type so that it matches the specified type. This is useful for reverse type-inference, where we want to infer that an object literal matches its constraint (much like how the java compiler does reverse-inference to figure out generics).

Overrides:

matchConstraint in class JSType

matchRecordTypeConstraint

public void matchRecordTypeConstraint(ObjectType constraintObj)

© 2009 Google - Privacy Policy - Terms and Conditions - About Google