1 /*

     2  * Copyright (c) 2010, 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 /*

    27  * This file is available under and governed by the GNU General Public

    28  * License version 2 only, as published by the Free Software Foundation.

    29  * However, the following notice accompanied the original version of this

    30  * file, and Oracle licenses the original version of this file under the BSD

    31  * license:

    32  */

    33 /*

    34    Copyright 2009-2013 Attila Szegedi

    35 

    36    Licensed under both the Apache License, Version 2.0 (the "Apache License")

    37    and the BSD License (the "BSD License"), with licensee being free to

    38    choose either of the two at their discretion.

    39 

    40    You may not use this file except in compliance with either the Apache

    41    License or the BSD License.

    42 

    43    If you choose to use this file in compliance with the Apache License, the

    44    following notice applies to you:

    45 

    46        You may obtain a copy of the Apache License at

    47 

    48            http://www.apache.org/licenses/LICENSE-2.0

    49 

    50        Unless required by applicable law or agreed to in writing, software

    51        distributed under the License is distributed on an "AS IS" BASIS,

    52        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or

    53        implied. See the License for the specific language governing

    54        permissions and limitations under the License.

    55 

    56    If you choose to use this file in compliance with the BSD License, the

    57    following notice applies to you:

    58 

    59        Redistribution and use in source and binary forms, with or without

    60        modification, are permitted provided that the following conditions are

    61        met:

    62        * Redistributions of source code must retain the above copyright

    63          notice, this list of conditions and the following disclaimer.

    64        * Redistributions in binary form must reproduce the above copyright

    65          notice, this list of conditions and the following disclaimer in the

    66          documentation and/or other materials provided with the distribution.

    67        * Neither the name of the copyright holder nor the names of

    68          contributors may be used to endorse or promote products derived from

    69          this software without specific prior written permission.

    70 

    71        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    72        IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

    73        TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

    74        PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER

    75        BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

    76        CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

    77        SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR

    78        BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

    79        WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

    80        OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

    81        ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    82 */

    83 

    84 package jdk.dynalink.beans;

    85 

    86 import java.lang.invoke.MethodHandle;

    87 import java.lang.invoke.MethodType;

    88 import java.util.Iterator;

    89 import java.util.LinkedList;

    90 import java.util.List;

    91 import jdk.dynalink.linker.ConversionComparator.Comparison;

    92 import jdk.dynalink.linker.LinkerServices;

    93 import jdk.dynalink.linker.support.TypeUtilities;

    94 

    95 /**

    96  * Utility class that encapsulates the algorithm for choosing the maximally specific methods.

    97  */

    98 class MaximallySpecific {

    99     /**

   100      * Given a list of methods, returns a list of maximally specific methods.

   101      *

   102      * @param methods the list of methods

   103      * @param varArgs whether to assume the methods are varargs

   104      * @return the list of maximally specific methods.

   105      */

   106     static List<SingleDynamicMethod> getMaximallySpecificMethods(final List<SingleDynamicMethod> methods, final boolean varArgs) {

   107         return getMaximallySpecificSingleDynamicMethods(methods, varArgs, null, null);

   108     }

   109 

   110     private abstract static class MethodTypeGetter<T> {

   111         abstract MethodType getMethodType(T t);

   112     }

   113 

   114     private static final MethodTypeGetter<MethodHandle> METHOD_HANDLE_TYPE_GETTER =

   115             new MethodTypeGetter<MethodHandle>() {

   116         @Override

   117         MethodType getMethodType(final MethodHandle t) {

   118             return t.type();

   119         }

   120     };

   121 

   122     private static final MethodTypeGetter<SingleDynamicMethod> DYNAMIC_METHOD_TYPE_GETTER =

   123             new MethodTypeGetter<SingleDynamicMethod>() {

   124         @Override

   125         MethodType getMethodType(final SingleDynamicMethod t) {

   126             return t.getMethodType();

   127         }

   128     };

   129 

   130      /**

   131       * Given a list of methods handles, returns a list of maximally specific methods, applying language-runtime

   132       * specific conversion preferences.

   133       *

   134       * @param methods the list of method handles

   135       * @param varArgs whether to assume the method handles are varargs

   136       * @param argTypes concrete argument types for the invocation

   137       * @return the list of maximally specific method handles.

   138       */

   139      static List<MethodHandle> getMaximallySpecificMethodHandles(final List<MethodHandle> methods, final boolean varArgs,

   140              final Class<?>[] argTypes, final LinkerServices ls) {

   141          return getMaximallySpecificMethods(methods, varArgs, argTypes, ls, METHOD_HANDLE_TYPE_GETTER);

   142      }

   143 

   144      /**

   145       * Given a list of methods, returns a list of maximally specific methods, applying language-runtime specific

   146       * conversion preferences.

   147       *

   148       * @param methods the list of methods

   149       * @param varArgs whether to assume the methods are varargs

   150       * @param argTypes concrete argument types for the invocation

   151       * @return the list of maximally specific methods.

   152       */

   153      static List<SingleDynamicMethod> getMaximallySpecificSingleDynamicMethods(final List<SingleDynamicMethod> methods,

   154              final boolean varArgs, final Class<?>[] argTypes, final LinkerServices ls) {

   155          return getMaximallySpecificMethods(methods, varArgs, argTypes, ls, DYNAMIC_METHOD_TYPE_GETTER);

   156      }

   157 

   158     /**

   159      * Given a list of methods, returns a list of maximally specific methods, applying language-runtime specific

   160      * conversion preferences.

   161      *

   162      * @param methods the list of methods

   163      * @param varArgs whether to assume the methods are varargs

   164      * @param argTypes concrete argument types for the invocation

   165      * @return the list of maximally specific methods.

   166      */

   167     private static <T> List<T> getMaximallySpecificMethods(final List<T> methods, final boolean varArgs,

   168             final Class<?>[] argTypes, final LinkerServices ls, final MethodTypeGetter<T> methodTypeGetter) {

   169         if(methods.size() < 2) {

   170             return methods;

   171         }

   172         final LinkedList<T> maximals = new LinkedList<>();

   173         for(final T m: methods) {

   174             final MethodType methodType = methodTypeGetter.getMethodType(m);

   175             boolean lessSpecific = false;

   176             for(final Iterator<T> maximal = maximals.iterator(); maximal.hasNext();) {

   177                 final T max = maximal.next();

   178                 switch(isMoreSpecific(methodType, methodTypeGetter.getMethodType(max), varArgs, argTypes, ls)) {

   179                     case TYPE_1_BETTER: {

   180                         maximal.remove();

   181                         break;

   182                     }

   183                     case TYPE_2_BETTER: {

   184                         lessSpecific = true;

   185                         break;

   186                     }

   187                     case INDETERMINATE: {

   188                         // do nothing

   189                         break;

   190                     }

   191                     default: {

   192                         throw new AssertionError();

   193                     }

   194                 }

   195             }

   196             if(!lessSpecific) {

   197                 maximals.addLast(m);

   198             }

   199         }

   200         return maximals;

   201     }

   202 

   203     private static Comparison isMoreSpecific(final MethodType t1, final MethodType t2, final boolean varArgs, final Class<?>[] argTypes,

   204             final LinkerServices ls) {

   205         final int pc1 = t1.parameterCount();

   206         final int pc2 = t2.parameterCount();

   207         assert varArgs || (pc1 == pc2) && (argTypes == null || argTypes.length == pc1);

   208         assert (argTypes == null) == (ls == null);

   209         final int maxPc = Math.max(Math.max(pc1, pc2), argTypes == null ? 0 : argTypes.length);

   210         boolean t1MoreSpecific = false;

   211         boolean t2MoreSpecific = false;

   212         // NOTE: Starting from 1 as overloaded method resolution doesn't depend on 0th element, which is the type of

   213         // 'this'. We're only dealing with instance methods here, not static methods. Actually, static methods will have

   214         // a fake 'this' of type StaticClass.

   215         for(int i = 1; i < maxPc; ++i) {

   216             final Class<?> c1 = getParameterClass(t1, pc1, i, varArgs);

   217             final Class<?> c2 = getParameterClass(t2, pc2, i, varArgs);

   218             if(c1 != c2) {

   219                 final Comparison cmp = compare(c1, c2, argTypes, i, ls);

   220                 if(cmp == Comparison.TYPE_1_BETTER && !t1MoreSpecific) {

   221                     t1MoreSpecific = true;

   222                     if(t2MoreSpecific) {

   223                         return Comparison.INDETERMINATE;

   224                     }

   225                 }

   226                 if(cmp == Comparison.TYPE_2_BETTER && !t2MoreSpecific) {

   227                     t2MoreSpecific = true;

   228                     if(t1MoreSpecific) {

   229                         return Comparison.INDETERMINATE;

   230                     }

   231                 }

   232             }

   233         }

   234         if(t1MoreSpecific) {

   235             return Comparison.TYPE_1_BETTER;

   236         } else if(t2MoreSpecific) {

   237             return Comparison.TYPE_2_BETTER;

   238         }

   239         return Comparison.INDETERMINATE;

   240     }

   241 

   242     private static Comparison compare(final Class<?> c1, final Class<?> c2, final Class<?>[] argTypes, final int i, final LinkerServices cmp) {

   243         if(cmp != null) {

   244             final Comparison c = cmp.compareConversion(argTypes[i], c1, c2);

   245             if(c != Comparison.INDETERMINATE) {

   246                 return c;

   247             }

   248         }

   249         if(TypeUtilities.isSubtype(c1, c2)) {

   250             return Comparison.TYPE_1_BETTER;

   251         } if(TypeUtilities.isSubtype(c2, c1)) {

   252             return Comparison.TYPE_2_BETTER;

   253         }

   254         return Comparison.INDETERMINATE;

   255     }

   256 

   257     private static Class<?> getParameterClass(final MethodType t, final int l, final int i, final boolean varArgs) {

   258         return varArgs && i >= l - 1 ? t.parameterType(l - 1).getComponentType() : t.parameterType(i);

   259     }

   260 }