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.util; 22 23import proguard.classfile.*; 24import proguard.classfile.constant.*; 25import proguard.classfile.constant.visitor.ConstantVisitor; 26 27/** 28 * This ConstantVisitor initializes any class references of all string constants 29 * it visits. More specifically, it fills out the references of string constant 30 * pool entries that happen to refer to a class in the program class pool or in 31 * the library class pool. 32 * 33 * @author Eric Lafortune 34 */ 35public class StringReferenceInitializer 36extends SimplifiedVisitor 37implements ConstantVisitor 38{ 39 private final ClassPool programClassPool; 40 private final ClassPool libraryClassPool; 41 42 43 /** 44 * Creates a new StringReferenceInitializer. 45 */ 46 public StringReferenceInitializer(ClassPool programClassPool, 47 ClassPool libraryClassPool) 48 { 49 this.programClassPool = programClassPool; 50 this.libraryClassPool = libraryClassPool; 51 } 52 53 54 // Implementations for ConstantVisitor. 55 56 public void visitAnyConstant(Clazz clazz, Constant constant) {} 57 58 59 public void visitStringConstant(Clazz clazz, StringConstant stringConstant) 60 { 61 if (stringConstant.referencedClass == null) 62 { 63 // See if we can find the referenced class. 64 stringConstant.referencedClass = 65 findClass(ClassUtil.internalClassName(stringConstant.getString(clazz))); 66 } 67 } 68 69 70 // Small utility methods. 71 72 /** 73 * Returns the class with the given name, either for the program class pool 74 * or from the library class pool, or <code>null</code> if it can't be found. 75 */ 76 private Clazz findClass(String name) 77 { 78 // First look for the class in the program class pool. 79 Clazz clazz = programClassPool.getClass(name); 80 81 // Otherwise look for the class in the library class pool. 82 if (clazz == null) 83 { 84 clazz = libraryClassPool.getClass(name); 85 } 86 87 return clazz; 88 } 89}