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1   /*
2    * Copyright (c) 2003, 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.repository;
27  
28  
29  import java.lang.reflect.Type;
30  import sun.reflect.generics.factory.GenericsFactory;
31  import sun.reflect.generics.tree.TypeSignature;
32  import sun.reflect.generics.parser.SignatureParser;
33  import sun.reflect.generics.visitor.Reifier;
34  
35  
36  
37  /**
38   * This class represents the generic type information for a constructor.
39   * The code is not dependent on a particular reflective implementation.
40   * It is designed to be used unchanged by at least core reflection and JDI.
41   */
42  public class FieldRepository extends AbstractRepository<TypeSignature> {
43  
44      private Type genericType; // caches the generic type info
45  
46   // protected, to enforce use of static factory yet allow subclassing
47      protected FieldRepository(String rawSig, GenericsFactory f) {
48        super(rawSig, f);
49      }
50  
51      protected TypeSignature parse(String s) {
52          return SignatureParser.make().parseTypeSig(s);
53      }
54  
55      /**
56       * Static factory method.
57       * @param rawSig - the generic signature of the reflective object
58       * that this repository is servicing
59       * @param f - a factory that will provide instances of reflective
60       * objects when this repository converts its AST
61       * @return a <tt>FieldRepository</tt> that manages the generic type
62       * information represented in the signature <tt>rawSig</tt>
63       */
64      public static FieldRepository make(String rawSig,
65                                               GenericsFactory f) {
66          return new FieldRepository(rawSig, f);
67      }
68  
69      // public API
70  
71   /*
72   * When queried for a particular piece of type information, the
73   * general pattern is to consult the corresponding cached value.
74   * If the corresponding field is non-null, it is returned.
75   * If not, it is created lazily. This is done by selecting the appropriate
76   * part of the tree and transforming it into a reflective object
77   * using a visitor.
78   * a visitor, which is created by feeding it the factory
79   * with which the repository was created.
80   */
81  
82      public Type getGenericType(){
83          if (genericType == null) { // lazily initialize generic type
84              Reifier r = getReifier(); // obtain visitor
85              getTree().accept(r); // reify subtree
86              // extract result from visitor and cache it
87              genericType = r.getResult();
88          }
89          return genericType; // return cached result
90      }
91  }