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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.attribute.preverification;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.attribute.CodeAttribute;
     25 import proguard.classfile.attribute.preverification.visitor.VerificationTypeVisitor;
     26 
     27 /**
     28  * This VerificationType represents a Null type.
     29  *
     30  * @author Eric Lafortune
     31  */
     32 public class NullType extends VerificationType
     33 {
     34     // Implementations for VerificationType.
     35 
     36     public int getTag()
     37     {
     38         return NULL_TYPE;
     39     }
     40 
     41 
     42     public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, VerificationTypeVisitor verificationTypeVisitor)
     43     {
     44         verificationTypeVisitor.visitNullType(clazz, method, codeAttribute, instructionOffset, this);
     45     }
     46 
     47 
     48     public void stackAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int stackIndex, VerificationTypeVisitor verificationTypeVisitor)
     49     {
     50         verificationTypeVisitor.visitStackNullType(clazz, method, codeAttribute, instructionOffset, stackIndex, this);
     51     }
     52 
     53 
     54     public void variablesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int variableIndex, VerificationTypeVisitor verificationTypeVisitor)
     55     {
     56         verificationTypeVisitor.visitVariablesNullType(clazz, method, codeAttribute, instructionOffset, variableIndex, this);
     57     }
     58 
     59 
     60     // Implementations for Object.
     61 
     62     public String toString()
     63     {
     64         return "n";
     65     }
     66 }
     67