1 /*
2 * Copyright (c) 2003, 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
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.annotation.*;
29 import java.lang.reflect.AnnotatedType;
30 import java.lang.reflect.Array;
31 import java.lang.reflect.GenericDeclaration;
32 import java.lang.reflect.Type;
33 import java.lang.reflect.TypeVariable;
34 import java.util.LinkedHashMap;
35 import java.util.Map;
36 import java.util.Objects;
37 import sun.reflect.annotation.AnnotationSupport;
38 import sun.reflect.annotation.TypeAnnotationParser;
39 import sun.reflect.annotation.AnnotationType;
40 import sun.reflect.generics.factory.GenericsFactory;
41 import sun.reflect.generics.tree.FieldTypeSignature;
42 import sun.reflect.generics.visitor.Reifier;
43
44 /**
45 * Implementation of <tt>java.lang.reflect.TypeVariable</tt> interface
46 * for core reflection.
47 */
48 public class TypeVariableImpl<D extends GenericDeclaration>
49 extends LazyReflectiveObjectGenerator implements TypeVariable<D> {
50 D genericDeclaration;
51 private String name;
52 // upper bounds - evaluated lazily
53 private Type[] bounds;
54
55 // The ASTs for the bounds. We are required to evaluate the bounds
56 // lazily, so we store these at least until we are first asked
57 // for the bounds. This also neatly solves the
58 // problem with F-bounds - you can't reify them before the formal
59 // is defined.
60 private FieldTypeSignature[] boundASTs;
61
62 // constructor is private to enforce access through static factory
63 private TypeVariableImpl(D decl, String n, FieldTypeSignature[] bs,
64 GenericsFactory f) {
65 super(f);
66 genericDeclaration = decl;
67 name = n;
68 boundASTs = bs;
69 }
70
71 // Accessors
72
73 // accessor for ASTs for bounds. Must not be called after
74 // bounds have been evaluated, because we might throw the ASTs
75 // away (but that is not thread-safe, is it?)
76 private FieldTypeSignature[] getBoundASTs() {
77 // check that bounds were not evaluated yet
78 assert(bounds == null);
79 return boundASTs;
80 }
81
82 /**
83 * Factory method.
84 * @param decl - the reflective object that declared the type variable
85 * that this method should create
86 * @param name - the name of the type variable to be returned
87 * @param bs - an array of ASTs representing the bounds for the type
88 * variable to be created
89 * @param f - a factory that can be used to manufacture reflective
90 * objects that represent the bounds of this type variable
91 * @return A type variable with name, bounds, declaration and factory
92 * specified
93 */
94 public static <T extends GenericDeclaration>
95 TypeVariableImpl<T> make(T decl, String name,
96 FieldTypeSignature[] bs,
97 GenericsFactory f) {
98 return new TypeVariableImpl<T>(decl, name, bs, f);
99 }
100
101
102 /**
103 * Returns an array of <tt>Type</tt> objects representing the
104 * upper bound(s) of this type variable. Note that if no upper bound is
105 * explicitly declared, the upper bound is <tt>Object</tt>.
106 *
107 * <p>For each upper bound B:
108 * <ul>
109 * <li>if B is a parameterized type or a type variable, it is created,
110 * (see {@link #ParameterizedType} for the details of the creation
111 * process for parameterized types).
112 * <li>Otherwise, B is resolved.
113 * </ul>
114 *
115 * @throws <tt>TypeNotPresentException</tt> if any of the
116 * bounds refers to a non-existent type declaration
117 * @throws <tt>MalformedParameterizedTypeException</tt> if any of the
118 * bounds refer to a parameterized type that cannot be instantiated
119 * for any reason
120 * @return an array of Types representing the upper bound(s) of this
121 * type variable
122 */
123 public Type[] getBounds() {
124 // lazily initialize bounds if necessary
125 if (bounds == null) {
126 FieldTypeSignature[] fts = getBoundASTs(); // get AST
127 // allocate result array; note that
128 // keeping ts and bounds separate helps with threads
129 Type[] ts = new Type[fts.length];
130 // iterate over bound trees, reifying each in turn
131 for ( int j = 0; j < fts.length; j++) {
132 Reifier r = getReifier();
133 fts[j].accept(r);
134 ts[j] = r.getResult();
135 }
136 // cache result
137 bounds = ts;
138 // could throw away bound ASTs here; thread safety?
139 }
140 return bounds.clone(); // return cached bounds
141 }
142
143 /**
144 * Returns the <tt>GenericDeclaration</tt> object representing the
145 * generic declaration that declared this type variable.
146 *
147 * @return the generic declaration that declared this type variable.
148 *
149 * @since 1.5
150 */
151 public D getGenericDeclaration(){
152 return genericDeclaration;
153 }
154
155
156 /**
157 * Returns the name of this type variable, as it occurs in the source code.
158 *
159 * @return the name of this type variable, as it appears in the source code
160 */
161 public String getName() { return name; }
162
163 public String toString() {return getName();}
164
165 @Override
166 public boolean equals(Object o) {
167 if (o instanceof TypeVariable) {
168 TypeVariable<?> that = (TypeVariable<?>) o;
169
170 GenericDeclaration thatDecl = that.getGenericDeclaration();
171 String thatName = that.getName();
172
173 return Objects.equals(genericDeclaration, thatDecl) &&
174 Objects.equals(name, thatName);
175
176 } else
177 return false;
178 }
179
180 @Override
181 public int hashCode() {
182 return genericDeclaration.hashCode() ^ name.hashCode();
183 }
184
185 // Implementations of AnnotatedElement methods.
186 @SuppressWarnings("unchecked")
187 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
188 Objects.requireNonNull(annotationClass);
189 // T is an Annotation type, the return value of get will be an annotation
190 return (T)mapAnnotations(getAnnotations()).get(annotationClass);
191 }
192
193 public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) {
194 Objects.requireNonNull(annotationClass);
195 return getAnnotation(annotationClass);
196 }
197
198 @Override
199 public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {
200 Objects.requireNonNull(annotationClass);
201 return AnnotationSupport.getMultipleAnnotations(mapAnnotations(getAnnotations()), annotationClass);
202 }
203
204 @Override
205 public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) {
206 Objects.requireNonNull(annotationClass);
207 return getAnnotationsByType(annotationClass);
208 }
209
210 public Annotation[] getAnnotations() {
211 int myIndex = typeVarIndex();
212 if (myIndex < 0)
213 throw new AssertionError("Index must be non-negative.");
214 return TypeAnnotationParser.parseTypeVariableAnnotations(getGenericDeclaration(), myIndex);
215 }
216
217 public Annotation[] getDeclaredAnnotations() {
218 return getAnnotations();
219 }
220
221 public AnnotatedType[] getAnnotatedBounds() {
222 return TypeAnnotationParser.parseAnnotatedBounds(getBounds(),
223 getGenericDeclaration(),
224 typeVarIndex());
225 }
226
227 private static final Annotation[] EMPTY_ANNOTATION_ARRAY = new Annotation[0];
228
229 // Helpers for annotation methods
230 private int typeVarIndex() {
231 TypeVariable<?>[] tVars = getGenericDeclaration().getTypeParameters();
232 int i = -1;
233 for (TypeVariable<?> v : tVars) {
234 i++;
235 if (equals(v))
236 return i;
237 }
238 return -1;
239 }
240
241 private static Map<Class<? extends Annotation>, Annotation> mapAnnotations(Annotation[] annos) {
242 Map<Class<? extends Annotation>, Annotation> result =
243 new LinkedHashMap<>();
244 for (Annotation a : annos) {
245 Class<? extends Annotation> klass = a.annotationType();
246 AnnotationType type = AnnotationType.getInstance(klass);
247 if (type.retention() == RetentionPolicy.RUNTIME)
248 if (result.put(klass, a) != null)
249 throw new AnnotationFormatError("Duplicate annotation for class: "+klass+": " + a);
250 }
251 return result;
252 }
253 }