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.optimize; 22 23import proguard.classfile.*; 24import proguard.classfile.util.SimplifiedVisitor; 25import proguard.classfile.visitor.MemberVisitor; 26import proguard.evaluation.value.Value; 27import proguard.optimize.evaluation.StoringInvocationUnit; 28 29/** 30 * This <code>MemberVisitor</code> delegates its visits to program class members 31 * to another given <code>MemberVisitor</code>, but only when the visited 32 * class member has been marked as a constant. 33 * 34 * @see StoringInvocationUnit 35 * @author Eric Lafortune 36 */ 37public class ConstantMemberFilter 38extends SimplifiedVisitor 39implements MemberVisitor 40{ 41 private final MemberVisitor constantMemberVisitor; 42 43 44 /** 45 * Creates a new ConstantMemberFilter. 46 * @param constantMemberVisitor the <code>MemberVisitor</code> to which 47 * visits to constant members will be delegated. 48 */ 49 public ConstantMemberFilter(MemberVisitor constantMemberVisitor) 50 { 51 this.constantMemberVisitor = constantMemberVisitor; 52 } 53 54 55 // Implementations for MemberVisitor. 56 57 public void visitProgramField(ProgramClass programClass, ProgramField programField) 58 { 59 Value value = StoringInvocationUnit.getFieldValue(programField); 60 if (value != null && 61 value.isParticular()) 62 { 63 constantMemberVisitor.visitProgramField(programClass, programField); 64 } 65 } 66 67 68 public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) 69 { 70 Value value = StoringInvocationUnit.getMethodReturnValue(programMethod); 71 if (value != null && 72 value.isParticular()) 73 { 74 constantMemberVisitor.visitProgramMethod(programClass, programMethod); 75 } 76 } 77} 78