<itemvalue="A visitor that will recursively visit all of the element in an element model. For example, using an instance of this class to visit a [CompilationUnitElement] will also cause all of the types in the compilation unit to be visited. Subclasses that override a visit method must either invoke the overridden visit method or must explicitly ask the visited element to visit its children. Failure to do so will cause the children of the visited element to not be visited. Clients may extend this class." />
<itemvalue="An AST visitor that will throw an exception if any of the visit methods that are invoked have not been overridden. It is intended to be a superclass for classes that implement the visitor pattern and need to (a) override all of the visit methods or (b) need to override a subset of the visit method and want to catch when any other visit methods have been invoked. Clients may extend this class." />
<itemvalue="A visitor that will do nothing when visiting an element. It is intended to be a superclass for classes that use the visitor pattern primarily as a dispatch mechanism (and hence don't need to recursively visit a whole structure) and that only need to visit a small number of element types. Clients may extend this class."/>
<itemvalue="An element visitor that will recursively visit all of the elements in an element model (like instances of the class [RecursiveElementVisitor]). In addition, when an element of a specific type is visited not only will the visit method for that specific type of element be invoked, but additional methods for the supertypes of that element will also be invoked. For example, using an instance of this class to visit a [MethodElement] will cause the method [visitMethodElement] to be invoked but will also cause the methods [visitExecutableElement] and [visitElement] to be subsequently invoked. This allows visitors to be written that visit all executable elements without needing to override the visit method for each of the specific subclasses of [ExecutableElement]. Note, however, that unlike many visitors, element visitors visit objects based on the interfaces implemented by those elements. Because interfaces form a graph structure rather than a tree structure the way classes do, and because it is generally undesirable for an object to be visited more than once, this class flattens the interface graph into a pseudo-tree. In particular, this class treats elements as if the element types were structured in the following way: <pre> Element ClassElement CompilationUnitElement ExecutableElement ConstructorElement LocalElement FunctionElement MethodElement PropertyAccessorElement ExportElement HtmlElement ImportElement LabelElement LibraryElement MultiplyDefinedElement PrefixElement TypeAliasElement TypeParameterElement UndefinedElement VariableElement PropertyInducingElement FieldElement TopLevelVariableElement LocalElement LocalVariableElement ParameterElement FieldFormalParameterElement <pre> Subclasses that override a visit method must either invoke the overridden visit method or explicitly invoke the more general visit method. Failure to do so will cause the visit methods for superclasses of the element to not be invoked and will cause the children of the visited node to not be visited. Clients may extend this class."/>
<itemvalue="A visitor that will recursively visit all of the element in an element model. For example, using an instance of this class to visit a [CompilationUnitElement] will also cause all of the types in the compilation unit to be visited. Subclasses that override a visit method must either invoke the overridden visit method or must explicitly ask the visited element to visit its children. Failure to do so will cause the children of the visited element to not be visited. Clients may extend this class."/>
<itemvalue="An object that can be used to visit an element structure. Clients may not extend, implement or mix-in this class. There are classes that implement this interface that provide useful default behaviors in `package:analyzerdartelementvisitor.dart`. A couple of the most useful include SimpleElementVisitor which implements every visit method by doing nothing, RecursiveElementVisitor which will cause every node in a structure to be visited, and ThrowingElementVisitor which implements every visit method by throwing an exception."/>
