src/share/classes/javax/lang/model/util/AbstractTypeVisitor8.java

Wed, 23 Jan 2013 20:11:07 -0800

author
darcy
date
Wed, 23 Jan 2013 20:11:07 -0800
changeset 1522
09f65aad4759
parent 1448
7d34e91f66bb
child 2525
2eb010b6cb22
permissions
-rw-r--r--

8006264: Add explanation of why default methods cannot be used in JDK 8 javax.lang.model
Reviewed-by: jjg

darcy@1054 1 /*
darcy@1522 2 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
darcy@1054 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
darcy@1054 4 *
darcy@1054 5 * This code is free software; you can redistribute it and/or modify it
darcy@1054 6 * under the terms of the GNU General Public License version 2 only, as
darcy@1054 7 * published by the Free Software Foundation. Oracle designates this
darcy@1054 8 * particular file as subject to the "Classpath" exception as provided
darcy@1054 9 * by Oracle in the LICENSE file that accompanied this code.
darcy@1054 10 *
darcy@1054 11 * This code is distributed in the hope that it will be useful, but WITHOUT
darcy@1054 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
darcy@1054 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
darcy@1054 14 * version 2 for more details (a copy is included in the LICENSE file that
darcy@1054 15 * accompanied this code).
darcy@1054 16 *
darcy@1054 17 * You should have received a copy of the GNU General Public License version
darcy@1054 18 * 2 along with this work; if not, write to the Free Software Foundation,
darcy@1054 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
darcy@1054 20 *
darcy@1054 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
darcy@1054 22 * or visit www.oracle.com if you need additional information or have any
darcy@1054 23 * questions.
darcy@1054 24 */
darcy@1054 25
darcy@1054 26 package javax.lang.model.util;
darcy@1054 27
darcy@1054 28 import javax.lang.model.type.*;
darcy@1054 29
darcy@1054 30 /**
darcy@1054 31 * A skeletal visitor of types with default behavior appropriate for
darcy@1054 32 * the {@link javax.lang.model.SourceVersion#RELEASE_8 RELEASE_8}
darcy@1054 33 * source version.
darcy@1054 34 *
darcy@1054 35 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
darcy@1054 36 * by this class may have methods added to it in the future to
darcy@1054 37 * accommodate new, currently unknown, language structures added to
darcy@1054 38 * future versions of the Java&trade; programming language.
darcy@1054 39 * Therefore, methods whose names begin with {@code "visit"} may be
darcy@1054 40 * added to this class in the future; to avoid incompatibilities,
darcy@1054 41 * classes which extend this class should not declare any instance
darcy@1054 42 * methods with names beginning with {@code "visit"}.
darcy@1054 43 *
darcy@1054 44 * <p>When such a new visit method is added, the default
darcy@1054 45 * implementation in this class will be to call the {@link
darcy@1054 46 * #visitUnknown visitUnknown} method. A new abstract type visitor
darcy@1054 47 * class will also be introduced to correspond to the new language
darcy@1054 48 * level; this visitor will have different default behavior for the
darcy@1054 49 * visit method in question. When the new visitor is introduced, all
darcy@1054 50 * or portions of this visitor may be deprecated.
darcy@1054 51 *
darcy@1522 52 * <p>Note that adding a default implementation of a new visit method
darcy@1522 53 * in a visitor class will occur instead of adding a <em>default
darcy@1522 54 * method</em> directly in the visitor interface since a Java SE 8
darcy@1522 55 * language feature cannot be used to this version of the API since
darcy@1522 56 * this version is required to be runnable on Java SE 7
darcy@1522 57 * implementations. Future versions of the API that are only required
darcy@1522 58 * to run on Java SE 8 and later may take advantage of default methods
darcy@1522 59 * in this situation.
darcy@1522 60 *
darcy@1054 61 * @param <R> the return type of this visitor's methods. Use {@link
darcy@1054 62 * Void} for visitors that do not need to return results.
darcy@1054 63 * @param <P> the type of the additional parameter to this visitor's
darcy@1054 64 * methods. Use {@code Void} for visitors that do not need an
darcy@1054 65 * additional parameter.
darcy@1054 66 *
darcy@1054 67 * @see AbstractTypeVisitor6
darcy@1054 68 * @see AbstractTypeVisitor7
darcy@1054 69 * @since 1.8
darcy@1054 70 */
darcy@1054 71 public abstract class AbstractTypeVisitor8<R, P> extends AbstractTypeVisitor7<R, P> {
darcy@1054 72 /**
darcy@1054 73 * Constructor for concrete subclasses to call.
darcy@1054 74 */
darcy@1054 75 protected AbstractTypeVisitor8() {
darcy@1054 76 super();
darcy@1054 77 }
mcimadamore@1436 78
mcimadamore@1436 79 /**
mcimadamore@1436 80 * Visits an {@code IntersectionType} in a manner defined by a subclass.
mcimadamore@1436 81 *
mcimadamore@1436 82 * @param t {@inheritDoc}
mcimadamore@1436 83 * @param p {@inheritDoc}
mcimadamore@1436 84 * @return the result of the visit as defined by a subclass
mcimadamore@1436 85 */
mcimadamore@1436 86 public abstract R visitIntersection(IntersectionType t, P p);
darcy@1054 87 }

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