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     /** The generic type info.  Lazily initialized. */
  45     private volatile Type genericType;
  46 
  47  // protected, to enforce use of static factory yet allow subclassing
  48     protected FieldRepository(String rawSig, GenericsFactory f) {
  49       super(rawSig, f);
  50     }
  51 
  52     protected TypeSignature parse(String s) {
  53         return SignatureParser.make().parseTypeSig(s);
  54     }
  55 
  56     /**
  57      * Static factory method.
  58      * @param rawSig - the generic signature of the reflective object
  59      * that this repository is servicing
  60      * @param f - a factory that will provide instances of reflective
  61      * objects when this repository converts its AST
  62      * @return a {@code FieldRepository} that manages the generic type
  63      * information represented in the signature {@code rawSig}
  64      */
  65     public static FieldRepository make(String rawSig, GenericsFactory f) {
  66         return new FieldRepository(rawSig, f);
  67     }
  68 
  69  /*
  70  * When queried for a particular piece of type information, the
  71  * general pattern is to consult the corresponding cached value.
  72  * If the corresponding field is non-null, it is returned.
  73  * If not, it is created lazily. This is done by selecting the appropriate
  74  * part of the tree and transforming it into a reflective object
  75  * using a visitor, which is created by feeding it the factory
  76  * with which the repository was created.
  77  */
  78 
  79     public Type getGenericType() {
  80         Type value = genericType;
  81         if (value == null) {
  82             value = computeGenericType();
  83             genericType = value;
  84         }
  85         return value;
  86     }
  87 
  88     private Type computeGenericType() {
  89         Reifier r = getReifier();       // obtain visitor
  90         getTree().accept(r);            // reify subtree
  91         return r.getResult();           // extract result from visitor
  92     }
  93 }