1 /*
2 * Copyright (c) 2003, 2004, 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
6 * under the terms of the GNU General Public License version 2 only, as
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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.reflect.generics.reflectiveObjects;
27
28 import java.lang.reflect.GenericDeclaration;
29 import java.lang.reflect.Type;
30 import java.lang.reflect.TypeVariable;
31
32 import sun.reflect.generics.factory.GenericsFactory;
33 import sun.reflect.generics.tree.FieldTypeSignature;
34 import sun.reflect.generics.visitor.Reifier;
35
36 /**
37 * Implementation of <tt>java.lang.reflect.TypeVariable</tt> interface
38 * for core reflection.
39 */
40 public class TypeVariableImpl<D extends GenericDeclaration>
41 extends LazyReflectiveObjectGenerator implements TypeVariable<D> {
42 D genericDeclaration;
43 private String name;
44 // upper bounds - evaluated lazily
45 private Type[] bounds;
46
47 // The ASTs for the bounds. We are required to evaluate the bounds
48 // lazily, so we store these at least until we are first asked
49 // for the bounds. This also neatly solves the
50 // problem with F-bounds - you can't reify them before the formal
51 // is defined.
52 private FieldTypeSignature[] boundASTs;
53
54 // constructor is private to enforce access through static factory
55 private TypeVariableImpl(D decl, String n, FieldTypeSignature[] bs,
56 GenericsFactory f) {
57 super(f);
58 genericDeclaration = decl;
59 name = n;
60 boundASTs = bs;
61 }
62
63 // Accessors
64
65 // accessor for ASTs for bounds. Must not be called after
66 // bounds have been evaluated, because we might throw the ASTs
67 // away (but that is not thread-safe, is it?)
68 private FieldTypeSignature[] getBoundASTs() {
69 // check that bounds were not evaluated yet
70 assert(bounds == null);
71 return boundASTs;
72 }
73
74 /**
75 * Factory method.
76 * @param decl - the reflective object that declared the type variable
77 * that this method should create
78 * @param name - the name of the type variable to be returned
79 * @param bs - an array of ASTs representing the bounds for the type
80 * variable to be created
81 * @param f - a factory that can be used to manufacture reflective
82 * objects that represent the bounds of this type variable
83 * @return A type variable with name, bounds, declaration and factory
84 * specified
85 */
86 public static <T extends GenericDeclaration>
87 TypeVariableImpl<T> make(T decl, String name,
88 FieldTypeSignature[] bs,
89 GenericsFactory f) {
90 return new TypeVariableImpl<T>(decl, name, bs, f);
91 }
92
93
94 /**
95 * Returns an array of <tt>Type</tt> objects representing the
96 * upper bound(s) of this type variable. Note that if no upper bound is
97 * explicitly declared, the upper bound is <tt>Object</tt>.
98 *
99 * <p>For each upper bound B:
100 * <ul>
101 * <li>if B is a parameterized type or a type variable, it is created,
102 * (see {@link #ParameterizedType} for the details of the creation
103 * process for parameterized types).
104 * <li>Otherwise, B is resolved.
105 * </ul>
106 *
107 * @throws <tt>TypeNotPresentException</tt> if any of the
108 * bounds refers to a non-existent type declaration
109 * @throws <tt>MalformedParameterizedTypeException</tt> if any of the
110 * bounds refer to a parameterized type that cannot be instantiated
111 * for any reason
112 * @return an array of Types representing the upper bound(s) of this
113 * type variable
114 */
115 public Type[] getBounds() {
116 // lazily initialize bounds if necessary
117 if (bounds == null) {
118 FieldTypeSignature[] fts = getBoundASTs(); // get AST
119 // allocate result array; note that
120 // keeping ts and bounds separate helps with threads
121 Type[] ts = new Type[fts.length];
122 // iterate over bound trees, reifying each in turn
123 for ( int j = 0; j < fts.length; j++) {
124 Reifier r = getReifier();
125 fts[j].accept(r);
126 ts[j] = r.getResult();
127 }
128 // cache result
129 bounds = ts;
130 // could throw away bound ASTs here; thread safety?
131 }
132 return bounds.clone(); // return cached bounds
133 }
134
135 /**
136 * Returns the <tt>GenericDeclaration</tt> object representing the
137 * generic declaration that declared this type variable.
138 *
139 * @return the generic declaration that declared this type variable.
140 *
141 * @since 1.5
142 */
143 public D getGenericDeclaration(){
144 return genericDeclaration;
145 }
146
147
148 /**
149 * Returns the name of this type variable, as it occurs in the source code.
150 *
151 * @return the name of this type variable, as it appears in the source code
152 */
153 public String getName() { return name; }
154
155 public String toString() {return getName();}
156
157 @Override
158 public boolean equals(Object o) {
159 if (o instanceof TypeVariable) {
160 TypeVariable<?> that = (TypeVariable<?>) o;
161
162 GenericDeclaration thatDecl = that.getGenericDeclaration();
163 String thatName = that.getName();
164
165 return
166 (genericDeclaration == null ?
167 thatDecl == null :
168 genericDeclaration.equals(thatDecl)) &&
169 (name == null ?
170 thatName == null :
171 name.equals(thatName));
172
173 } else
174 return false;
175 }
176
177 @Override
178 public int hashCode() {
179 return genericDeclaration.hashCode() ^ name.hashCode();
180 }
181 }