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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.classfile.visitor;
     22 
     23 import proguard.classfile.*;
     24 
     25 
     26 /**
     27  * This <code>ClassVisitor</code>     delegates its visits to another given
     28  * <code>ClassVisitor</code>, but only when the visited class
     29  * has the proper access flags.
     30  *
     31  * @see ClassConstants
     32  *
     33  * @author Eric Lafortune
     34  */
     35 public class ClassAccessFilter implements ClassVisitor
     36 {
     37     private final int          requiredSetAccessFlags;
     38     private final int          requiredUnsetAccessFlags;
     39     private final ClassVisitor classVisitor;
     40 
     41 
     42     /**
     43      * Creates a new ClassAccessFilter.
     44      * @param requiredSetAccessFlags   the class access flags that should be
     45      *                                 set.
     46      * @param requiredUnsetAccessFlags the class access flags that should be
     47      *                                 unset.
     48      * @param classVisitor             the <code>ClassVisitor</code> to
     49      *                                 which visits will be delegated.
     50      */
     51     public ClassAccessFilter(int          requiredSetAccessFlags,
     52                              int          requiredUnsetAccessFlags,
     53                              ClassVisitor classVisitor)
     54     {
     55         this.requiredSetAccessFlags   = requiredSetAccessFlags;
     56         this.requiredUnsetAccessFlags = requiredUnsetAccessFlags;
     57         this.classVisitor             = classVisitor;
     58     }
     59 
     60 
     61     // Implementations for ClassVisitor.
     62 
     63     public void visitProgramClass(ProgramClass programClass)
     64     {
     65         if (accepted(programClass.getAccessFlags()))
     66         {
     67             classVisitor.visitProgramClass(programClass);
     68         }
     69     }
     70 
     71 
     72     public void visitLibraryClass(LibraryClass libraryClass)
     73     {
     74         if (accepted(libraryClass.getAccessFlags()))
     75         {
     76             classVisitor.visitLibraryClass(libraryClass);
     77         }
     78     }
     79 
     80 
     81     // Small utility methods.
     82 
     83     private boolean accepted(int accessFlags)
     84     {
     85         return (requiredSetAccessFlags   & ~accessFlags) == 0 &&
     86                (requiredUnsetAccessFlags &  accessFlags) == 0;
     87     }
     88 }
     89