001 /*
002 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package javax.lang.model.type;
027
028 import javax.lang.model.element.*;
029 import javax.lang.model.util.Types;
030
031 /**
032 * Represents a type in the Java programming language.
033 * Types include primitive types, declared types (class and interface types),
034 * array types, type variables, and the null type.
035 * Also represented are wildcard type arguments,
036 * the signature and return types of executables,
037 * and pseudo-types corresponding to packages and to the keyword {@code void}.
038 *
039 * <p> Types should be compared using the utility methods in {@link
040 * Types}. There is no guarantee that any particular type will always
041 * be represented by the same object.
042 *
043 * <p> To implement operations based on the class of an {@code
044 * TypeMirror} object, either use a {@linkplain TypeVisitor visitor}
045 * or use the result of the {@link #getKind} method. Using {@code
046 * instanceof} is <em>not</em> necessarily a reliable idiom for
047 * determining the effective class of an object in this modeling
048 * hierarchy since an implementation may choose to have a single
049 * object implement multiple {@code TypeMirror} subinterfaces.
050 *
051 * @author Joseph D. Darcy
052 * @author Scott Seligman
053 * @author Peter von der Ahé
054 * @version 1.12 07/05/05
055 * @see Element
056 * @see Types
057 * @since 1.6
058 */
059 public interface TypeMirror {
060
061 /**
062 * Returns the {@code kind} of this type.
063 *
064 * @return the kind of this type
065 */
066 TypeKind getKind();
067
068 /**
069 * Obeys the general contract of {@link Object#equals Object.equals}.
070 * This method does not, however, indicate whether two types represent
071 * the same type.
072 * Semantic comparisons of type equality should instead use
073 * {@link Types#isSameType(TypeMirror, TypeMirror)}.
074 * The results of {@code t1.equals(t2)} and
075 * {@code Types.isSameType(t1, t2)} may differ.
076 *
077 * @param obj the object to be compared with this type
078 * @return {@code true} if the specified object is equal to this one
079 */
080 boolean equals(Object obj);
081
082 /**
083 * Obeys the general contract of {@link Object#hashCode Object.hashCode}.
084 *
085 * @see #equals
086 */
087 int hashCode();
088
089 /**
090 * Returns an informative string representation of this type. If
091 * possible, the string should be of a form suitable for
092 * representing this type in source code. Any names embedded in
093 * the result are qualified if possible.
094 *
095 * @return a string representation of this type
096 */
097 String toString();
098
099 /**
100 * Applies a visitor to this type.
101 *
102 * @param <R> the return type of the visitor's methods
103 * @param <P> the type of the additional parameter to the visitor's methods
104 * @param v the visitor operating on this type
105 * @param p additional parameter to the visitor
106 * @return a visitor-specified result
107 */
108 <R, P> R accept(TypeVisitor<R, P> v, P p);
109 }
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