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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.shrink;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.visitor.MemberVisitor;
     25 
     26 /**
     27  * This MemberVisitor delegates all its method calls to another MemberVisitor,
     28  * but only for Member objects that are marked as used.
     29  *
     30  * @see UsageMarker
     31  *
     32  * @author Eric Lafortune
     33  */
     34 public class UsedMemberFilter
     35 implements   MemberVisitor
     36 {
     37     private final UsageMarker   usageMarker;
     38     private final MemberVisitor memberVisitor;
     39 
     40 
     41     /**
     42      * Creates a new UsedMemberFilter.
     43      * @param usageMarker   the usage marker that is used to mark the classes
     44      *                      and class members.
     45      * @param memberVisitor the member visitor to which the visiting will be
     46      *                      delegated.
     47      */
     48     public UsedMemberFilter(UsageMarker   usageMarker,
     49                             MemberVisitor memberVisitor)
     50     {
     51         this.usageMarker   = usageMarker;
     52         this.memberVisitor = memberVisitor;
     53     }
     54 
     55 
     56     // Implementations for MemberVisitor.
     57 
     58 
     59     public void visitProgramField(ProgramClass programClass, ProgramField programField)
     60     {
     61         if (usageMarker.isUsed(programField))
     62         {
     63             memberVisitor.visitProgramField(programClass, programField);
     64         }
     65     }
     66 
     67 
     68     public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
     69     {
     70         if (usageMarker.isUsed(programMethod))
     71         {
     72             memberVisitor.visitProgramMethod(programClass, programMethod);
     73         }
     74     }
     75 
     76 
     77     public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
     78     {
     79         if (usageMarker.isUsed(libraryField))
     80         {
     81             memberVisitor.visitLibraryField(libraryClass, libraryField);
     82         }
     83     }
     84 
     85 
     86     public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
     87     {
     88         if (usageMarker.isUsed(libraryMethod))
     89         {
     90             memberVisitor.visitLibraryMethod(libraryClass, libraryMethod);
     91         }
     92     }
     93 }
     94