Summary

Add the suite of FooVisitor9 types in the usual way for the javax.lang.model API, deprecate the FooVisitor6 types, and add missing @SupportedSourceVersion annotations.

Problem

With a new platform release, the time has come to define javax.lang.model utility visitor appropriate for the release.

Solution

Besides adding the new FooVisitor9 types, also:

• Deprecate the FooVisitor6 types

• Add missing @SupportedSourceVersion  annotations to AbstractTypeVisitor{6, 7, 8}.

Specification

Deprecate the following classes:

AbstractAnnotationValueVisitor6
AbstractElementVisitor6
AbstractTypeVisitor6
ElementKindVisitor6
ElementScanner6
SimpleAnnotationValueVisitor6
SimpleElementVisitor6
SimpleTypeVisitor6
TypeKindVisitor6

Add @SupportedSourceVersion annotations as follows:

@SupportedSourceVersion(RELEASE_6) to AbstractTypeVisitor6
@SupportedSourceVersion(RELEASE_7) to AbstractTypeVisitor7
@SupportedSourceVersion(RELEASE_8) to AbstractTypeVisitor8

Add the following types:

AbstractAnnotationValueVisitor9
AbstractElementVisitor9
AbstractTypeVisitor9
ElementKindVisitor9
ElementScanner9
SimpleAnnotationValueVisitor9
SimpleElementVisitor9
SimpleTypeVisitor9
TypeKindVisitor9

Specification of those types below:

+/**
+ * A skeletal visitor for annotation values with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.
+ *
+ * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} interface
+ * implemented by this class may have methods added to it in the
+ * future to accommodate new, currently unknown, language structures
+ * added to future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new abstract annotation
+ * value visitor class will also be introduced to correspond to the
+ * new language level; this visitor will have different default
+ * behavior for the visit method in question.  When the new visitor is
+ * introduced, all or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods
+ * @param <P> the type of the additional parameter to this visitor's methods.
+ *
+ * @see AbstractAnnotationValueVisitor6
+ * @see AbstractAnnotationValueVisitor7
+ * @see AbstractAnnotationValueVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public abstract class AbstractAnnotationValueVisitor9<R, P> extends AbstractAnnotationValueVisitor8<R, P> {
+
+    /**
+     * Constructor for concrete subclasses to call.
+     */
+    protected AbstractAnnotationValueVisitor9() {
+        super();
+    }
+}

+/**
+ * A skeletal visitor of program elements with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.
+ *
+ * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
+ * implemented by this class may have methods added to it in the
+ * future to accommodate new, currently unknown, language structures
+ * added to future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new abstract element visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see AbstractElementVisitor6
+ * @see AbstractElementVisitor7
+ * @see AbstractElementVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public abstract class AbstractElementVisitor9<R, P> extends AbstractElementVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses to call.
+     */
+    protected AbstractElementVisitor9(){
+        super();
+    }
+}

+/**
+ * A skeletal visitor of types with default behavior appropriate for
+ * the {@link javax.lang.model.SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.
+ *
+ * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
+ * by this class may have methods added to it in the future to
+ * accommodate new, currently unknown, language structures added to
+ * future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new abstract type visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see AbstractTypeVisitor6
+ * @see AbstractTypeVisitor7
+ * @see AbstractTypeVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public abstract class AbstractTypeVisitor9<R, P> extends AbstractTypeVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses to call.
+     */
+    protected AbstractTypeVisitor9() {
+        super();
+    }
+}

+/**
+ * A visitor of program elements based on their {@linkplain
+ * ElementKind kind} with default behavior appropriate for the {@link
+ * SourceVersion#RELEASE_9 RELEASE_9} source version.  For {@linkplain
+ * Element elements} <tt><i>XYZ</i></tt> that may have more than one
+ * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
+ * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
+ * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods
+ * call {@link #defaultAction defaultAction}, passing their arguments
+ * to {@code defaultAction}'s corresponding parameters.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
+ * implemented by this class may have methods added to it or the
+ * {@code ElementKind} {@code enum} used in this case may have
+ * constants added to it in the future to accommodate new, currently
+ * unknown, language structures added to future versions of the
+ * Java&trade; programming language.  Therefore, methods whose names
+ * begin with {@code "visit"} may be added to this class in the
+ * future; to avoid incompatibilities, classes which extend this class
+ * should not declare any instance methods with names beginning with
+ * {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new abstract element kind
+ * visitor class will also be introduced to correspond to the new
+ * language level; this visitor will have different default behavior
+ * for the visit method in question.  When the new visitor is
+ * introduced, all or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see ElementKindVisitor6
+ * @see ElementKindVisitor7
+ * @see ElementKindVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class ElementKindVisitor9<R, P> extends ElementKindVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected ElementKindVisitor9() {
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected ElementKindVisitor9(R defaultValue) {
+        super(defaultValue);
+    }
+}

+/**
+ * A scanning visitor of program elements with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.  The <tt>visit<i>XYZ</i></tt> methods in this
+ * class scan their component elements by calling {@code scan} on
+ * their {@linkplain Element#getEnclosedElements enclosed elements},
+ * {@linkplain ExecutableElement#getParameters parameters}, etc., as
+ * indicated in the individual method specifications.  A subclass can
+ * control the order elements are visited by overriding the
+ * <tt>visit<i>XYZ</i></tt> methods.  Note that clients of a scanner
+ * may get the desired behavior be invoking {@code v.scan(e, p)} rather
+ * than {@code v.visit(e, p)} on the root objects of interest.
+ *
+ * <p>When a subclass overrides a <tt>visit<i>XYZ</i></tt> method, the
+ * new method can cause the enclosed elements to be scanned in the
+ * default way by calling <tt>super.visit<i>XYZ</i></tt>.  In this
+ * fashion, the concrete visitor can control the ordering of traversal
+ * over the component elements with respect to the additional
+ * processing; for example, consistently calling
+ * <tt>super.visit<i>XYZ</i></tt> at the start of the overridden
+ * methods will yield a preorder traversal, etc.  If the component
+ * elements should be traversed in some other order, instead of
+ * calling <tt>super.visit<i>XYZ</i></tt>, an overriding visit method
+ * should call {@code scan} with the elements in the desired order.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
+ * implemented by this class may have methods added to it in the
+ * future to accommodate new, currently unknown, language structures
+ * added to future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new element scanner visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see ElementScanner6
+ * @see ElementScanner7
+ * @see ElementScanner8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class ElementScanner9<R, P> extends ElementScanner8<R, P> {
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected ElementScanner9(){
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the default value
+     */
+    protected ElementScanner9(R defaultValue){
+        super(defaultValue);
+    }
+}

+/**
+ * A simple visitor for annotation values with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.  Visit methods call {@link #defaultAction
+ * defaultAction} passing their arguments to {@code defaultAction}'s
+ * corresponding parameters.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} interface
+ * implemented by this class may have methods added to it in the
+ * future to accommodate new, currently unknown, language structures
+ * added to future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new simple annotation
+ * value visitor class will also be introduced to correspond to the
+ * new language level; this visitor will have different default
+ * behavior for the visit method in question.  When the new visitor is
+ * introduced, all or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods
+ * @param <P> the type of the additional parameter to this visitor's methods.
+ *
+ * @see SimpleAnnotationValueVisitor6
+ * @see SimpleAnnotationValueVisitor7
+ * @see SimpleAnnotationValueVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class SimpleAnnotationValueVisitor9<R, P> extends SimpleAnnotationValueVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected SimpleAnnotationValueVisitor9() {
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected SimpleAnnotationValueVisitor9(R defaultValue) {
+        super(defaultValue);
+    }
+}


+/**
+ * A simple visitor of program elements with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_9 RELEASE_9}
+ * source version.
+ *
+ * Visit methods corresponding to {@code RELEASE_9} and earlier
+ * language constructs call {@link #defaultAction defaultAction},
+ * passing their arguments to {@code defaultAction}'s corresponding
+ * parameters.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code ElementVisitor} interface
+ * implemented by this class may have methods added to it in the
+ * future to accommodate new, currently unknown, language structures
+ * added to future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new simple element visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@code Void}
+ *             for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's methods.  Use {@code Void}
+ *              for visitors that do not need an additional parameter.
+ *
+ * @see SimpleElementVisitor6
+ * @see SimpleElementVisitor7
+ * @see SimpleElementVisitor8
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class SimpleElementVisitor9<R, P> extends SimpleElementVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected SimpleElementVisitor9(){
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected SimpleElementVisitor9(R defaultValue){
+        super(defaultValue);
+    }
+}

+/**
+ * A simple visitor of types with default behavior appropriate for the
+ * {@link SourceVersion#RELEASE_9 RELEASE_9} source version.
+ *
+ * Visit methods corresponding to {@code RELEASE_8} and earlier
+ * language constructs call {@link #defaultAction defaultAction},
+ * passing their arguments to {@code defaultAction}'s corresponding
+ * parameters.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
+ * by this class may have methods added to it in the future to
+ * accommodate new, currently unknown, language structures added to
+ * future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new simple type visitor
+ * class will also be introduced to correspond to the new language
+ * level; this visitor will have different default behavior for the
+ * visit method in question.  When the new visitor is introduced, all
+ * or portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see SimpleTypeVisitor6
+ * @see SimpleTypeVisitor7
+ * @since 1.8
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class SimpleTypeVisitor9<R, P> extends SimpleTypeVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected SimpleTypeVisitor9(){
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected SimpleTypeVisitor9(R defaultValue){
+        super(defaultValue);
+    }
+}


+/**
+ * A visitor of types based on their {@linkplain TypeKind kind} with
+ * default behavior appropriate for the {@link SourceVersion#RELEASE_9
+ * RELEASE_9} source version.  For {@linkplain
+ * TypeMirror types} <tt><i>XYZ</i></tt> that may have more than one
+ * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
+ * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
+ * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> methods
+ * call {@link #defaultAction defaultAction}, passing their arguments
+ * to {@code defaultAction}'s corresponding parameters.
+ *
+ * <p> Methods in this class may be overridden subject to their
+ * general contract.  Note that annotating methods in concrete
+ * subclasses with {@link java.lang.Override @Override} will help
+ * ensure that methods are overridden as intended.
+ *
+ * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
+ * by this class may have methods added to it in the future to
+ * accommodate new, currently unknown, language structures added to
+ * future versions of the Java&trade; programming language.
+ * Therefore, methods whose names begin with {@code "visit"} may be
+ * added to this class in the future; to avoid incompatibilities,
+ * classes which extend this class should not declare any instance
+ * methods with names beginning with {@code "visit"}.
+ *
+ * <p>When such a new visit method is added, the default
+ * implementation in this class will be to call the {@link
+ * #visitUnknown visitUnknown} method.  A new type kind visitor class
+ * will also be introduced to correspond to the new language level;
+ * this visitor will have different default behavior for the visit
+ * method in question.  When the new visitor is introduced, all or
+ * portions of this visitor may be deprecated.
+ *
+ * @param <R> the return type of this visitor's methods.  Use {@link
+ *            Void} for visitors that do not need to return results.
+ * @param <P> the type of the additional parameter to this visitor's
+ *            methods.  Use {@code Void} for visitors that do not need an
+ *            additional parameter.
+ *
+ * @see TypeKindVisitor6
+ * @see TypeKindVisitor7
+ * @since 1.9
+ */
+@SupportedSourceVersion(RELEASE_9)
+public class TypeKindVisitor9<R, P> extends TypeKindVisitor8<R, P> {
+    /**
+     * Constructor for concrete subclasses to call; uses {@code null}
+     * for the default value.
+     */
+    protected TypeKindVisitor9() {
+        super(null);
+    }
+
+    /**
+     * Constructor for concrete subclasses to call; uses the argument
+     * for the default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected TypeKindVisitor9(R defaultValue) {
+        super(defaultValue);
+    }
+}