1 /* 2 * Javassist, a Java-bytecode translator toolkit. 3 * Copyright (C) 1999-2007 Shigeru Chiba. All Rights Reserved. 4 * 5 * The contents of this file are subject to the Mozilla Public License Version 6 * 1.1 (the "License"); you may not use this file except in compliance with 7 * the License. Alternatively, the contents of this file may be used under 8 * the terms of the GNU Lesser General Public License Version 2.1 or later. 9 * 10 * Software distributed under the License is distributed on an "AS IS" basis, 11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License 12 * for the specific language governing rights and limitations under the 13 * License. 14 */ 15 16 package javassist.compiler.ast; 17 18 import javassist.compiler.CompileError; 19 20 /** 21 * A linked list. 22 * The right subtree must be an ASTList object or null. 23 */ 24 public class ASTList extends ASTree { 25 private ASTree left; 26 private ASTList right; 27 28 public ASTList(ASTree _head, ASTList _tail) { 29 left = _head; 30 right = _tail; 31 } 32 33 public ASTList(ASTree _head) { 34 left = _head; 35 right = null; 36 } 37 38 public static ASTList make(ASTree e1, ASTree e2, ASTree e3) { 39 return new ASTList(e1, new ASTList(e2, new ASTList(e3))); 40 } 41 42 public ASTree getLeft() { return left; } 43 44 public ASTree getRight() { return right; } 45 46 public void setLeft(ASTree _left) { left = _left; } 47 48 public void setRight(ASTree _right) { 49 right = (ASTList)_right; 50 } 51 52 /** 53 * Returns the car part of the list. 54 */ 55 public ASTree head() { return left; } 56 57 public void setHead(ASTree _head) { 58 left = _head; 59 } 60 61 /** 62 * Returns the cdr part of the list. 63 */ 64 public ASTList tail() { return right; } 65 66 public void setTail(ASTList _tail) { 67 right = _tail; 68 } 69 70 public void accept(Visitor v) throws CompileError { v.atASTList(this); } 71 72 public String toString() { 73 StringBuffer sbuf = new StringBuffer(); 74 sbuf.append("(<"); 75 sbuf.append(getTag()); 76 sbuf.append('>'); 77 ASTList list = this; 78 while (list != null) { 79 sbuf.append(' '); 80 ASTree a = list.left; 81 sbuf.append(a == null ? "<null>" : a.toString()); 82 list = list.right; 83 } 84 85 sbuf.append(')'); 86 return sbuf.toString(); 87 } 88 89 /** 90 * Returns the number of the elements in this list. 91 */ 92 public int length() { 93 return length(this); 94 } 95 96 public static int length(ASTList list) { 97 if (list == null) 98 return 0; 99 100 int n = 0; 101 while (list != null) { 102 list = list.right; 103 ++n; 104 } 105 106 return n; 107 } 108 109 /** 110 * Returns a sub list of the list. The sub list begins with the 111 * n-th element of the list. 112 * 113 * @param nth zero or more than zero. 114 */ 115 public ASTList sublist(int nth) { 116 ASTList list = this; 117 while (nth-- > 0) 118 list = list.right; 119 120 return list; 121 } 122 123 /** 124 * Substitutes <code>newObj</code> for <code>oldObj</code> in the 125 * list. 126 */ 127 public boolean subst(ASTree newObj, ASTree oldObj) { 128 for (ASTList list = this; list != null; list = list.right) 129 if (list.left == oldObj) { 130 list.left = newObj; 131 return true; 132 } 133 134 return false; 135 } 136 137 /** 138 * Appends an object to a list. 139 */ 140 public static ASTList append(ASTList a, ASTree b) { 141 return concat(a, new ASTList(b)); 142 } 143 144 /** 145 * Concatenates two lists. 146 */ 147 public static ASTList concat(ASTList a, ASTList b) { 148 if (a == null) 149 return b; 150 else { 151 ASTList list = a; 152 while (list.right != null) 153 list = list.right; 154 155 list.right = b; 156 return a; 157 } 158 } 159 } 160
