1/* 2 * ProGuard -- shrinking, optimization, obfuscation, and preverification 3 * of Java bytecode. 4 * 5 * Copyright (c) 2002-2009 Eric Lafortune (eric@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 */ 21package proguard.classfile.visitor; 22 23import proguard.classfile.*; 24 25 26/** 27 * This <code>MemberVisitor</code> delegates its visits to another given 28 * <code>MemberVisitor</code>, but only when the visited member has the proper 29 * access flags. 30 * <p> 31 * If conflicting access flags (public/private/protected) are specified, 32 * having one of them set will be considered sufficient. 33 * 34 * @see ClassConstants 35 * 36 * @author Eric Lafortune 37 */ 38public class MemberAccessFilter 39implements MemberVisitor 40{ 41 // A mask of conflicting access flags. These are interpreted in a special 42 // way if more of them are required at the same time. In that case, one 43 // of them being set is sufficient. 44 private static final int ACCESS_MASK = 45 ClassConstants.INTERNAL_ACC_PUBLIC | 46 ClassConstants.INTERNAL_ACC_PRIVATE | 47 ClassConstants.INTERNAL_ACC_PROTECTED; 48 49 private final int requiredSetAccessFlags; 50 private final int requiredUnsetAccessFlags; 51 private final int requiredOneSetAccessFlags; 52 private final MemberVisitor memberVisitor; 53 54 55 /** 56 * Creates a new MemberAccessFilter. 57 * @param requiredSetAccessFlags the class access flags that should be 58 * set. 59 * @param requiredUnsetAccessFlags the class access flags that should be 60 * unset. 61 * @param memberVisitor the <code>MemberVisitor</code> to 62 * which visits will be delegated. 63 */ 64 public MemberAccessFilter(int requiredSetAccessFlags, 65 int requiredUnsetAccessFlags, 66 MemberVisitor memberVisitor) 67 { 68 this.requiredSetAccessFlags = requiredSetAccessFlags & ~ACCESS_MASK; 69 this.requiredUnsetAccessFlags = requiredUnsetAccessFlags; 70 this.requiredOneSetAccessFlags = requiredSetAccessFlags & ACCESS_MASK; 71 this.memberVisitor = memberVisitor; 72 } 73 74 75 // Implementations for MemberVisitor. 76 77 public void visitProgramField(ProgramClass programClass, ProgramField programField) 78 { 79 if (accepted(programField.getAccessFlags())) 80 { 81 memberVisitor.visitProgramField(programClass, programField); 82 } 83 } 84 85 86 public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) 87 { 88 if (accepted(programMethod.getAccessFlags())) 89 { 90 memberVisitor.visitProgramMethod(programClass, programMethod); 91 } 92 } 93 94 95 public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField) 96 { 97 if (accepted(libraryField.getAccessFlags())) 98 { 99 memberVisitor.visitLibraryField(libraryClass, libraryField); 100 } 101 } 102 103 104 public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) 105 { 106 if (accepted(libraryMethod.getAccessFlags())) 107 { 108 memberVisitor.visitLibraryMethod(libraryClass, libraryMethod); 109 } 110 } 111 112 113 // Small utility methods. 114 115 private boolean accepted(int accessFlags) 116 { 117 return (requiredSetAccessFlags & ~accessFlags) == 0 && 118 (requiredUnsetAccessFlags & accessFlags) == 0 && 119 (requiredOneSetAccessFlags == 0 || 120 (requiredOneSetAccessFlags & accessFlags) != 0); 121 } 122} 123