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   }