src/share/classes/com/sun/tools/javac/util/ListBuffer.java

Sat, 01 Dec 2007 00:00:00 +0000

author
duke
date
Sat, 01 Dec 2007 00:00:00 +0000
changeset 1
9a66ca7c79fa
child 70
62fcf8d73dc5
permissions
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duke@1 1 /*
duke@1 2 * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
duke@1 7 * published by the Free Software Foundation. Sun designates this
duke@1 8 * particular file as subject to the "Classpath" exception as provided
duke@1 9 * by Sun in the LICENSE file that accompanied this code.
duke@1 10 *
duke@1 11 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 14 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 15 * accompanied this code).
duke@1 16 *
duke@1 17 * You should have received a copy of the GNU General Public License version
duke@1 18 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 20 *
duke@1 21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@1 22 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@1 23 * have any questions.
duke@1 24 */
duke@1 25
duke@1 26 package com.sun.tools.javac.util;
duke@1 27
duke@1 28 import java.util.Collection;
duke@1 29 import java.util.Iterator;
duke@1 30 import java.util.NoSuchElementException;
duke@1 31
duke@1 32 /** A class for constructing lists by appending elements. Modelled after
duke@1 33 * java.lang.StringBuffer.
duke@1 34 *
duke@1 35 * <p><b>This is NOT part of any API supported by Sun Microsystems. If
duke@1 36 * you write code that depends on this, you do so at your own risk.
duke@1 37 * This code and its internal interfaces are subject to change or
duke@1 38 * deletion without notice.</b>
duke@1 39 */
duke@1 40 public class ListBuffer<A> implements Collection<A> {
duke@1 41
duke@1 42 public static <T> ListBuffer<T> lb() {
duke@1 43 return new ListBuffer<T>();
duke@1 44 }
duke@1 45
duke@1 46 /** The list of elements of this buffer.
duke@1 47 */
duke@1 48 public List<A> elems;
duke@1 49
duke@1 50 /** A pointer pointing to the last, sentinel element of `elems'.
duke@1 51 */
duke@1 52 public List<A> last;
duke@1 53
duke@1 54 /** The number of element in this buffer.
duke@1 55 */
duke@1 56 public int count;
duke@1 57
duke@1 58 /** Has a list been created from this buffer yet?
duke@1 59 */
duke@1 60 public boolean shared;
duke@1 61
duke@1 62 /** Create a new initially empty list buffer.
duke@1 63 */
duke@1 64 public ListBuffer() {
duke@1 65 clear();
duke@1 66 }
duke@1 67
duke@1 68 public final void clear() {
duke@1 69 this.elems = new List<A>(null,null);
duke@1 70 this.last = this.elems;
duke@1 71 count = 0;
duke@1 72 shared = false;
duke@1 73 }
duke@1 74
duke@1 75 /** Return the number of elements in this buffer.
duke@1 76 */
duke@1 77 public int length() {
duke@1 78 return count;
duke@1 79 }
duke@1 80 public int size() {
duke@1 81 return count;
duke@1 82 }
duke@1 83
duke@1 84 /** Is buffer empty?
duke@1 85 */
duke@1 86 public boolean isEmpty() {
duke@1 87 return count == 0;
duke@1 88 }
duke@1 89
duke@1 90 /** Is buffer not empty?
duke@1 91 */
duke@1 92 public boolean nonEmpty() {
duke@1 93 return count != 0;
duke@1 94 }
duke@1 95
duke@1 96 /** Copy list and sets last.
duke@1 97 */
duke@1 98 private void copy() {
duke@1 99 List<A> p = elems = new List<A>(elems.head, elems.tail);
duke@1 100 while (true) {
duke@1 101 List<A> tail = p.tail;
duke@1 102 if (tail == null) break;
duke@1 103 tail = new List<A>(tail.head, tail.tail);
duke@1 104 p.setTail(tail);
duke@1 105 p = tail;
duke@1 106 }
duke@1 107 last = p;
duke@1 108 shared = false;
duke@1 109 }
duke@1 110
duke@1 111 /** Prepend an element to buffer.
duke@1 112 */
duke@1 113 public ListBuffer<A> prepend(A x) {
duke@1 114 elems = elems.prepend(x);
duke@1 115 count++;
duke@1 116 return this;
duke@1 117 }
duke@1 118
duke@1 119 /** Append an element to buffer.
duke@1 120 */
duke@1 121 public ListBuffer<A> append(A x) {
duke@1 122 if (shared) copy();
duke@1 123 last.head = x;
duke@1 124 last.setTail(new List<A>(null,null));
duke@1 125 last = last.tail;
duke@1 126 count++;
duke@1 127 return this;
duke@1 128 }
duke@1 129
duke@1 130 /** Append all elements in a list to buffer.
duke@1 131 */
duke@1 132 public ListBuffer<A> appendList(List<A> xs) {
duke@1 133 while (xs.nonEmpty()) {
duke@1 134 append(xs.head);
duke@1 135 xs = xs.tail;
duke@1 136 }
duke@1 137 return this;
duke@1 138 }
duke@1 139
duke@1 140 /** Append all elements in a list to buffer.
duke@1 141 */
duke@1 142 public ListBuffer<A> appendList(ListBuffer<A> xs) {
duke@1 143 return appendList(xs.toList());
duke@1 144 }
duke@1 145
duke@1 146 /** Append all elements in an array to buffer.
duke@1 147 */
duke@1 148 public ListBuffer<A> appendArray(A[] xs) {
duke@1 149 for (int i = 0; i < xs.length; i++) {
duke@1 150 append(xs[i]);
duke@1 151 }
duke@1 152 return this;
duke@1 153 }
duke@1 154
duke@1 155 /** Convert buffer to a list of all its elements.
duke@1 156 */
duke@1 157 public List<A> toList() {
duke@1 158 shared = true;
duke@1 159 return elems;
duke@1 160 }
duke@1 161
duke@1 162 /** Does the list contain the specified element?
duke@1 163 */
duke@1 164 public boolean contains(Object x) {
duke@1 165 return elems.contains(x);
duke@1 166 }
duke@1 167
duke@1 168 /** Convert buffer to an array
duke@1 169 */
duke@1 170 public <T> T[] toArray(T[] vec) {
duke@1 171 return elems.toArray(vec);
duke@1 172 }
duke@1 173 public Object[] toArray() {
duke@1 174 return toArray(new Object[size()]);
duke@1 175 }
duke@1 176
duke@1 177 /** The first element in this buffer.
duke@1 178 */
duke@1 179 public A first() {
duke@1 180 return elems.head;
duke@1 181 }
duke@1 182
duke@1 183 /** Remove the first element in this buffer.
duke@1 184 */
duke@1 185 public void remove() {
duke@1 186 if (elems != last) {
duke@1 187 elems = elems.tail;
duke@1 188 count--;
duke@1 189 }
duke@1 190 }
duke@1 191
duke@1 192 /** Return first element in this buffer and remove
duke@1 193 */
duke@1 194 public A next() {
duke@1 195 A x = elems.head;
duke@1 196 remove();
duke@1 197 return x;
duke@1 198 }
duke@1 199
duke@1 200 /** An enumeration of all elements in this buffer.
duke@1 201 */
duke@1 202 public Iterator<A> iterator() {
duke@1 203 return new Iterator<A>() {
duke@1 204 List<A> elems = ListBuffer.this.elems;
duke@1 205 public boolean hasNext() {
duke@1 206 return elems != last;
duke@1 207 }
duke@1 208 public A next() {
duke@1 209 if (elems == last)
duke@1 210 throw new NoSuchElementException();
duke@1 211 A elem = elems.head;
duke@1 212 elems = elems.tail;
duke@1 213 return elem;
duke@1 214 }
duke@1 215 public void remove() {
duke@1 216 throw new UnsupportedOperationException();
duke@1 217 }
duke@1 218 };
duke@1 219 }
duke@1 220
duke@1 221 public boolean add(A a) {
duke@1 222 throw new UnsupportedOperationException();
duke@1 223 }
duke@1 224 public boolean remove(Object o) {
duke@1 225 throw new UnsupportedOperationException();
duke@1 226 }
duke@1 227 public boolean containsAll(Collection<?> c) {
duke@1 228 throw new UnsupportedOperationException();
duke@1 229 }
duke@1 230 public boolean addAll(Collection<? extends A> c) {
duke@1 231 throw new UnsupportedOperationException();
duke@1 232 }
duke@1 233 public boolean removeAll(Collection<?> c) {
duke@1 234 throw new UnsupportedOperationException();
duke@1 235 }
duke@1 236 public boolean retainAll(Collection<?> c) {
duke@1 237 throw new UnsupportedOperationException();
duke@1 238 }
duke@1 239 }

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