langtools/src/java.compiler/share/classes/javax/lang/model/util/SimpleElementVisitor6.java
changeset 25874 83c19f00452c
parent 25690 b1dac768ab79
child 43147 823bfbf9e914
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/java.compiler/share/classes/javax/lang/model/util/SimpleElementVisitor6.java	Sun Aug 17 15:52:32 2014 +0100
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package javax.lang.model.util;
+
+import javax.lang.model.element.*;
+import javax.annotation.processing.SupportedSourceVersion;
+import javax.lang.model.SourceVersion;
+import static javax.lang.model.SourceVersion.*;
+
+
+/**
+ * A simple visitor of program elements with default behavior
+ * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
+ * source version.
+ *
+ * Visit methods corresponding to {@code RELEASE_6} language
+ * constructs call {@link #defaultAction defaultAction}, passing their
+ * arguments to {@code defaultAction}'s corresponding parameters.
+ *
+ * For constructs introduced in {@code RELEASE_7} and later, {@code
+ * visitUnknown} is called instead.
+ *
+ * <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.
+ *
+ * <p>Note that adding a default implementation of a new visit method
+ * in a visitor class will occur instead of adding a <em>default
+ * method</em> directly in the visitor interface since a Java SE 8
+ * language feature cannot be used to this version of the API since
+ * this version is required to be runnable on Java SE 7
+ * implementations.  Future versions of the API that are only required
+ * to run on Java SE 8 and later may take advantage of default methods
+ * in this situation.
+ *
+ * @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.
+ *
+ * @author Joseph D. Darcy
+ * @author Scott Seligman
+ * @author Peter von der Ah&eacute;
+ *
+ * @see SimpleElementVisitor7
+ * @see SimpleElementVisitor8
+ * @see SimpleElementVisitor9
+ * @since 1.6
+ * @deprecated Release 6 is obsolete; update to a visitor for a newer
+ * release level.
+ */
+@Deprecated
+@SupportedSourceVersion(RELEASE_6)
+public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> {
+    /**
+     * Default value to be returned; {@link #defaultAction
+     * defaultAction} returns this value unless the method is
+     * overridden.
+     */
+    protected final R DEFAULT_VALUE;
+
+    /**
+     * Constructor for concrete subclasses; uses {@code null} for the
+     * default value.
+     */
+    protected SimpleElementVisitor6(){
+        DEFAULT_VALUE = null;
+    }
+
+    /**
+     * Constructor for concrete subclasses; uses the argument for the
+     * default value.
+     *
+     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
+     */
+    protected SimpleElementVisitor6(R defaultValue){
+        DEFAULT_VALUE = defaultValue;
+    }
+    /**
+     * The default action for visit methods.  The implementation in
+     * this class just returns {@link #DEFAULT_VALUE}; subclasses will
+     * commonly override this method.
+     *
+     * @param e the element to process
+     * @param p a visitor-specified parameter
+     * @return {@code DEFAULT_VALUE} unless overridden
+     */
+    protected R defaultAction(Element e, P p) {
+        return DEFAULT_VALUE;
+    }
+
+    /**
+     * {@inheritDoc} This implementation calls {@code defaultAction}.
+     *
+     * @param e {@inheritDoc}
+     * @param p {@inheritDoc}
+     * @return  the result of {@code defaultAction}
+     */
+    public R visitPackage(PackageElement e, P p) {
+        return defaultAction(e, p);
+    }
+
+    /**
+     * {@inheritDoc} This implementation calls {@code defaultAction}.
+     *
+     * @param e {@inheritDoc}
+     * @param p {@inheritDoc}
+     * @return  the result of {@code defaultAction}
+     */
+    public R visitType(TypeElement e, P p) {
+        return defaultAction(e, p);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * This implementation calls {@code defaultAction}, unless the
+     * element is a {@code RESOURCE_VARIABLE} in which case {@code
+     * visitUnknown} is called.
+     *
+     * @param e {@inheritDoc}
+     * @param p {@inheritDoc}
+     * @return  the result of {@code defaultAction} or {@code visitUnknown}
+     */
+    public R visitVariable(VariableElement e, P p) {
+        if (e.getKind() != ElementKind.RESOURCE_VARIABLE)
+            return defaultAction(e, p);
+        else
+            return visitUnknown(e, p);
+    }
+
+    /**
+     * {@inheritDoc} This implementation calls {@code defaultAction}.
+     *
+     * @param e {@inheritDoc}
+     * @param p {@inheritDoc}
+     * @return  the result of {@code defaultAction}
+     */
+    public R visitExecutable(ExecutableElement e, P p) {
+        return defaultAction(e, p);
+    }
+
+    /**
+     * {@inheritDoc} This implementation calls {@code defaultAction}.
+     *
+     * @param e {@inheritDoc}
+     * @param p {@inheritDoc}
+     * @return  the result of {@code defaultAction}
+     */
+    public R visitTypeParameter(TypeParameterElement e, P p) {
+        return defaultAction(e, p);
+    }
+}