duke@1: /*
darcy@1522: * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
duke@1: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1: *
duke@1: * This code is free software; you can redistribute it and/or modify it
duke@1: * under the terms of the GNU General Public License version 2 only, as
ohair@554: * published by the Free Software Foundation. Oracle designates this
duke@1: * particular file as subject to the "Classpath" exception as provided
ohair@554: * by Oracle in the LICENSE file that accompanied this code.
duke@1: *
duke@1: * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1: * version 2 for more details (a copy is included in the LICENSE file that
duke@1: * accompanied this code).
duke@1: *
duke@1: * You should have received a copy of the GNU General Public License version
duke@1: * 2 along with this work; if not, write to the Free Software Foundation,
duke@1: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1: *
ohair@554: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554: * or visit www.oracle.com if you need additional information or have any
ohair@554: * questions.
duke@1: */
duke@1:
duke@1: package javax.lang.model.util;
duke@1:
jjg@1357: import javax.annotation.processing.SupportedSourceVersion;
jjg@1357: import javax.lang.model.SourceVersion;
duke@1: import javax.lang.model.element.*;
duke@1: import static javax.lang.model.SourceVersion.*;
duke@1:
duke@1:
duke@1: /**
duke@1: * A skeletal visitor of program elements with default behavior
duke@1: * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
duke@1: * source version.
duke@1: *
duke@1: * WARNING: The {@code ElementVisitor} interface
duke@1: * implemented by this class may have methods added to it in the
duke@1: * future to accommodate new, currently unknown, language structures
duke@1: * added to future versions of the Java™ programming language.
duke@1: * Therefore, methods whose names begin with {@code "visit"} may be
duke@1: * added to this class in the future; to avoid incompatibilities,
duke@1: * classes which extend this class should not declare any instance
duke@1: * methods with names beginning with {@code "visit"}.
duke@1: *
duke@1: *
When such a new visit method is added, the default
duke@1: * implementation in this class will be to call the {@link
duke@1: * #visitUnknown visitUnknown} method. A new abstract element visitor
duke@1: * class will also be introduced to correspond to the new language
duke@1: * level; this visitor will have different default behavior for the
duke@1: * visit method in question. When the new visitor is introduced, all
duke@1: * or portions of this visitor may be deprecated.
duke@1: *
darcy@1522: *
Note that adding a default implementation of a new visit method
darcy@1522: * in a visitor class will occur instead of adding a default
darcy@1522: * method directly in the visitor interface since a Java SE 8
darcy@1522: * language feature cannot be used to this version of the API since
darcy@1522: * this version is required to be runnable on Java SE 7
darcy@1522: * implementations. Future versions of the API that are only required
darcy@1522: * to run on Java SE 8 and later may take advantage of default methods
darcy@1522: * in this situation.
darcy@1522: *
duke@1: * @param the return type of this visitor's methods. Use {@link
duke@1: * Void} for visitors that do not need to return results.
duke@1: * @param the type of the additional parameter to this visitor's
duke@1: * methods. Use {@code Void} for visitors that do not need an
duke@1: * additional parameter.
duke@1: *
duke@1: * @author Joseph D. Darcy
duke@1: * @author Scott Seligman
duke@1: * @author Peter von der Ahé
darcy@575: *
darcy@575: * @see AbstractElementVisitor7
darcy@1054: * @see AbstractElementVisitor8
duke@1: * @since 1.6
duke@1: */
duke@1: @SupportedSourceVersion(RELEASE_6)
duke@1: public abstract class AbstractElementVisitor6 implements ElementVisitor {
duke@1: /**
duke@1: * Constructor for concrete subclasses to call.
duke@1: */
duke@1: protected AbstractElementVisitor6(){}
duke@1:
duke@1: /**
duke@1: * Visits any program element as if by passing itself to that
duke@1: * element's {@link Element#accept accept} method. The invocation
duke@1: * {@code v.visit(elem)} is equivalent to {@code elem.accept(v,
duke@1: * p)}.
duke@1: *
duke@1: * @param e the element to visit
duke@1: * @param p a visitor-specified parameter
duke@1: * @return a visitor-specified result
duke@1: */
duke@1: public final R visit(Element e, P p) {
duke@1: return e.accept(this, p);
duke@1: }
duke@1:
duke@1: /**
duke@1: * Visits any program element as if by passing itself to that
duke@1: * element's {@link Element#accept accept} method and passing
duke@1: * {@code null} for the additional parameter. The invocation
duke@1: * {@code v.visit(elem)} is equivalent to {@code elem.accept(v,
duke@1: * null)}.
duke@1: *
duke@1: * @param e the element to visit
duke@1: * @return a visitor-specified result
duke@1: */
duke@1: public final R visit(Element e) {
duke@1: return e.accept(this, null);
duke@1: }
duke@1:
duke@1: /**
duke@1: * {@inheritDoc}
duke@1: *
duke@1: * The default implementation of this method in
duke@1: * {@code AbstractElementVisitor6} will always throw
duke@1: * {@code UnknownElementException}.
duke@1: * This behavior is not required of a subclass.
duke@1: *
duke@1: * @param e the element to visit
duke@1: * @param p a visitor-specified parameter
duke@1: * @return a visitor-specified result
duke@1: * @throws UnknownElementException
duke@1: * a visitor implementation may optionally throw this exception
duke@1: */
duke@1: public R visitUnknown(Element e, P p) {
duke@1: throw new UnknownElementException(e, p);
duke@1: }
duke@1: }