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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2014 Eric Lafortune (eric (at) graphics.cornell.edu)
      6  *
      7  * This program is free software; you can redistribute it and/or modify it
      8  * under the terms of the GNU General Public License as published by the Free
      9  * Software Foundation; either version 2 of the License, or (at your option)
     10  * any later version.
     11  *
     12  * This program is distributed in the hope that it will be useful, but WITHOUT
     13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
     15  * more details.
     16  *
     17  * You should have received a copy of the GNU General Public License along
     18  * with this program; if not, write to the Free Software Foundation, Inc.,
     19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
     20  */
     21 package proguard.optimize.evaluation;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.visitor.*;
     25 import proguard.optimize.info.SimpleEnumMarker;
     26 
     27 /**
     28  * This ClassVisitor marks all program classes that it visits as simple enums,
     29  * if their methods qualify.
     30  *
     31  * @author Eric Lafortune
     32  */
     33 public class SimpleEnumClassChecker
     34 implements   ClassVisitor
     35 {
     36     //*
     37     private static final boolean DEBUG = false;
     38     /*/
     39     private static       boolean DEBUG = System.getProperty("enum") != null;
     40     //*/
     41 
     42 
     43     private final SimpleEnumMarker simpleEnumMarker     = new SimpleEnumMarker(true);
     44     private final MemberVisitor    virtualMethodChecker = new MemberAccessFilter(0,
     45                                                                                  ClassConstants.ACC_PRIVATE |
     46                                                                                  ClassConstants.ACC_STATIC,
     47                                                           new MemberToClassVisitor(
     48                                                           new SimpleEnumMarker(false)));
     49 
     50 
     51     // Implementations for ClassVisitor.
     52 
     53     public void visitLibraryClass(LibraryClass libraryClass) {}
     54 
     55     public void visitProgramClass(ProgramClass programClass)
     56     {
     57         // Does the class have the simple enum constructor?
     58         if (programClass.findMethod(ClassConstants.METHOD_NAME_INIT,
     59                                     ClassConstants.METHOD_TYPE_INIT_ENUM) != null)
     60         {
     61             if (DEBUG)
     62             {
     63                 System.out.println("SimpleEnumClassChecker: ["+programClass.getName()+"] is a candidate simple enum, without extra fields");
     64             }
     65 
     66             // Mark it.
     67             simpleEnumMarker.visitProgramClass(programClass);
     68 
     69             // However, unmark it again if it has any non-private, non-static
     70             // methods.
     71             programClass.methodsAccept(virtualMethodChecker);
     72         }
     73     }
     74 }