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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2009 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> lets a given <code>ClassVisitor</code>
     28  * travel to the first concrete subclasses down in its hierarchy of abstract
     29  * classes and concrete classes.
     30  *
     31  * @author Eric Lafortune
     32  */
     33 public class ConcreteClassDownTraveler
     34 implements   ClassVisitor
     35 {
     36     private final ClassVisitor classVisitor;
     37 
     38 
     39     /**
     40      * Creates a new ConcreteClassDownTraveler.
     41      * @param classVisitor     the <code>ClassVisitor</code> to
     42      *                         which visits will be delegated.
     43      */
     44     public ConcreteClassDownTraveler(ClassVisitor classVisitor)
     45     {
     46         this.classVisitor = classVisitor;
     47     }
     48 
     49 
     50     // Implementations for ClassVisitor.
     51 
     52     public void visitProgramClass(ProgramClass programClass)
     53     {
     54         // Is this an abstract class or an interface?
     55         if ((programClass.getAccessFlags() &
     56              (ClassConstants.INTERNAL_ACC_INTERFACE |
     57               ClassConstants.INTERNAL_ACC_ABSTRACT)) != 0)
     58         {
     59             // Travel down the hierarchy.
     60             Clazz[] subClasses = programClass.subClasses;
     61             if (subClasses != null)
     62             {
     63                 for (int index = 0; index < subClasses.length; index++)
     64                 {
     65                     subClasses[index].accept(this);
     66                 }
     67             }
     68         }
     69         else
     70         {
     71             // Visit the class. Don't descend any further.
     72             programClass.accept(classVisitor);
     73         }
     74     }
     75 
     76 
     77     public void visitLibraryClass(LibraryClass libraryClass)
     78     {
     79         // Is this an abstract class or interface?
     80         if ((libraryClass.getAccessFlags() &
     81              (ClassConstants.INTERNAL_ACC_INTERFACE |
     82               ClassConstants.INTERNAL_ACC_ABSTRACT)) != 0)
     83         {
     84             // Travel down the hierarchy.
     85             Clazz[] subClasses = libraryClass.subClasses;
     86             if (subClasses != null)
     87             {
     88                 for (int index = 0; index < subClasses.length; index++)
     89                 {
     90                     subClasses[index].accept(this);
     91                 }
     92             }
     93         }
     94         else
     95         {
     96             // Visit the class. Don't descend any further.
     97             libraryClass.accept(classVisitor);
     98         }
     99     }
    100 }
    101