TypeMirror.java revision 2571:10fc81ac75b4 
1/*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25
26package javax.lang.model.type;
27
28import java.lang.annotation.Annotation;
29import java.util.List;
30import javax.lang.model.element.*;
31import javax.lang.model.util.Types;
32
33/**
34 * Represents a type in the Java programming language.
35 * Types include primitive types, declared types (class and interface types),
36 * array types, type variables, and the null type.
37 * Also represented are wildcard type arguments,
38 * the signature and return types of executables,
39 * and pseudo-types corresponding to packages and to the keyword {@code void}.
40 *
41 * <p> Types should be compared using the utility methods in {@link
42 * Types}.  There is no guarantee that any particular type will always
43 * be represented by the same object.
44 *
45 * <p> To implement operations based on the class of an {@code
46 * TypeMirror} object, either use a {@linkplain TypeVisitor visitor}
47 * or use the result of the {@link #getKind} method.  Using {@code
48 * instanceof} is <em>not</em> necessarily a reliable idiom for
49 * determining the effective class of an object in this modeling
50 * hierarchy since an implementation may choose to have a single
51 * object implement multiple {@code TypeMirror} subinterfaces.
52 *
53 * @author Joseph D. Darcy
54 * @author Scott Seligman
55 * @author Peter von der Ah&eacute;
56 * @see Element
57 * @see Types
58 * @since 1.6
59 */
60public interface TypeMirror extends javax.lang.model.AnnotatedConstruct {
61
62    /**
63     * Returns the {@code kind} of this type.
64     *
65     * @return the kind of this type
66     */
67    TypeKind getKind();
68
69    /**
70     * Obeys the general contract of {@link Object#equals Object.equals}.
71     * This method does not, however, indicate whether two types represent
72     * the same type.
73     * Semantic comparisons of type equality should instead use
74     * {@link Types#isSameType(TypeMirror, TypeMirror)}.
75     * The results of {@code t1.equals(t2)} and
76     * {@code Types.isSameType(t1, t2)} may differ.
77     *
78     * @param obj  the object to be compared with this type
79     * @return {@code true} if the specified object is equal to this one
80     */
81    boolean equals(Object obj);
82
83    /**
84     * Obeys the general contract of {@link Object#hashCode Object.hashCode}.
85     *
86     * @see #equals
87     */
88    int hashCode();
89
90    /**
91     * Returns an informative string representation of this type.  If
92     * possible, the string should be of a form suitable for
93     * representing this type in source code.  Any names embedded in
94     * the result are qualified if possible.
95     *
96     * @return a string representation of this type
97     */
98    String toString();
99
100    /**
101     * Applies a visitor to this type.
102     *
103     * @param <R> the return type of the visitor's methods
104     * @param <P> the type of the additional parameter to the visitor's methods
105     * @param v   the visitor operating on this type
106     * @param p   additional parameter to the visitor
107     * @return a visitor-specified result
108     */
109    <R, P> R accept(TypeVisitor<R, P> v, P p);
110}
111