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 
  29 import java.lang.reflect.Type;
  30 import java.lang.reflect.WildcardType;
  31 import sun.reflect.generics.factory.GenericsFactory;
  32 import sun.reflect.generics.tree.FieldTypeSignature;
  33 import sun.reflect.generics.visitor.Reifier;
  34 import java.util.Arrays;
  35 
  36 
  37 /**
  38  * Implementation of WildcardType interface for core reflection.
  39  */
  40 public class WildcardTypeImpl extends LazyReflectiveObjectGenerator
  41     implements WildcardType {
  42 
  43     /*
  44      * We are required to evaluate the bounds lazily, so we store them as ASTs
  45      * until we are first asked for them.  This also neatly solves the problem
  46      * with F-bounds - you can't reify them before the formal is defined.
  47      */
  48 
  49     /** The upper bounds.  Lazily converted from FieldTypeSignature[] to Type[]. */
  50     private volatile Object[] upperBounds;
  51 
  52     /** The lower bounds.  Lazily converted from FieldTypeSignature[] to Type[]. */
  53     private volatile Object[] lowerBounds;
  54 
  55     // constructor is private to enforce access through static factory
  56     private WildcardTypeImpl(FieldTypeSignature[] ubs,
  57                              FieldTypeSignature[] lbs,
  58                              GenericsFactory f) {
  59         super(f);
  60         upperBounds = ubs;
  61         lowerBounds = lbs;
  62     }
  63 
  64     /**
  65      * Factory method.
  66      * @param ubs - an array of ASTs representing the upper bounds for the type
  67      * variable to be created
  68      * @param lbs - an array of ASTs representing the lower bounds for the type
  69      * variable to be created
  70      * @param f - a factory that can be used to manufacture reflective
  71      * objects that represent the bounds of this wildcard type
  72      * @return a wild card type with the requested bounds and factory
  73      */
  74     public static WildcardTypeImpl make(FieldTypeSignature[] ubs,
  75                                         FieldTypeSignature[] lbs,
  76                                         GenericsFactory f) {
  77         return new WildcardTypeImpl(ubs, lbs, f);
  78     }
  79 
  80     /**
  81      * Returns an array of <tt>Type</tt> objects representing the upper
  82      * bound(s) of this type variable.  Note that if no upper bound is
  83      * explicitly declared, the upper bound is <tt>Object</tt>.
  84      *
  85      * <p>For each upper bound B :
  86      * <ul>
  87      *  <li>if B is a parameterized type or a type variable, it is created,
  88      *  (see {@link #ParameterizedType} for the details of the creation
  89      *  process for parameterized types).
  90      *  <li>Otherwise, B is resolved.
  91      * </ul>
  92      *
  93      * @return an array of Types representing the upper bound(s) of this
  94      *     type variable
  95      * @throws <tt>TypeNotPresentException</tt> if any of the
  96      *     bounds refers to a non-existent type declaration
  97      * @throws <tt>MalformedParameterizedTypeException</tt> if any of the
  98      *     bounds refer to a parameterized type that cannot be instantiated
  99      *     for any reason
 100      */
 101     public Type[] getUpperBounds() {
 102         Object[] value = upperBounds;
 103         if (value instanceof FieldTypeSignature[]) {
 104             value = reifyBounds((FieldTypeSignature[])value);
 105             upperBounds = value;
 106         }
 107         return (Type[])value.clone();
 108     }
 109 
 110     /**
 111      * Returns an array of <tt>Type</tt> objects representing the
 112      * lower bound(s) of this type variable.  Note that if no lower bound is
 113      * explicitly declared, the lower bound is the type of <tt>null</tt>.
 114      * In this case, a zero length array is returned.
 115      *
 116      * <p>For each lower bound B :
 117      * <ul>
 118      *   <li>if B is a parameterized type or a type variable, it is created,
 119      *   (see {@link #ParameterizedType} for the details of the creation
 120      *   process for parameterized types).
 121      *   <li>Otherwise, B is resolved.
 122      * </ul>
 123      *
 124      * @return an array of Types representing the lower bound(s) of this
 125      *     type variable
 126      * @throws <tt>TypeNotPresentException</tt> if any of the
 127      *     bounds refers to a non-existent type declaration
 128      * @throws <tt>MalformedParameterizedTypeException</tt> if any of the
 129      *     bounds refer to a parameterized type that cannot be instantiated
 130      *     for any reason
 131      */
 132     public Type[] getLowerBounds() {
 133         Object[] value = lowerBounds;
 134         if (value instanceof FieldTypeSignature[]) {
 135             value = reifyBounds((FieldTypeSignature[])value);
 136             lowerBounds = value;
 137         }
 138         return (Type[])value.clone();
 139     }
 140 
 141     public String toString() {
 142         Type[] lowerBounds = getLowerBounds();
 143         Type[] bounds = lowerBounds;
 144         StringBuilder sb = new StringBuilder();
 145 
 146         if (lowerBounds.length > 0)
 147             sb.append("? super ");
 148         else {
 149             Type[] upperBounds = getUpperBounds();
 150             if (upperBounds.length > 0 && !upperBounds[0].equals(Object.class) ) {
 151                 bounds = upperBounds;
 152                 sb.append("? extends ");
 153             } else
 154                 return "?";
 155         }
 156 
 157         assert bounds.length > 0;
 158 
 159         boolean first = true;
 160         for(Type bound: bounds) {
 161             if (!first)
 162                 sb.append(" & ");
 163 
 164             first = false;
 165             sb.append(bound.getTypeName());
 166         }
 167         return sb.toString();
 168     }
 169 
 170     @Override
 171     public boolean equals(Object o) {
 172         if (o instanceof WildcardType) {
 173             WildcardType that = (WildcardType) o;
 174             return
 175                 Arrays.equals(this.getLowerBounds(),
 176                               that.getLowerBounds()) &&
 177                 Arrays.equals(this.getUpperBounds(),
 178                               that.getUpperBounds());
 179         } else
 180             return false;
 181     }
 182 
 183     @Override
 184     public int hashCode() {
 185         Type [] lowerBounds = getLowerBounds();
 186         Type [] upperBounds = getUpperBounds();
 187 
 188         return Arrays.hashCode(lowerBounds) ^ Arrays.hashCode(upperBounds);
 189     }
 190 }