1.1 --- a/src/share/classes/com/sun/tools/javac/util/ListBuffer.java Tue Dec 11 15:05:55 2012 -0800
1.2 +++ b/src/share/classes/com/sun/tools/javac/util/ListBuffer.java Wed Dec 12 20:26:56 2012 +0100
1.3 @@ -1,5 +1,5 @@
1.4 /*
1.5 - * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
1.6 + * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.8 *
1.9 * This code is free software; you can redistribute it and/or modify it
1.10 @@ -52,19 +52,20 @@
1.11
1.12 /** The list of elements of this buffer.
1.13 */
1.14 - public List<A> elems;
1.15 + private List<A> elems;
1.16
1.17 - /** A pointer pointing to the last, sentinel element of `elems'.
1.18 + /** A pointer pointing to the last element of 'elems' containing data,
1.19 + * or null if the list is empty.
1.20 */
1.21 - public List<A> last;
1.22 + private List<A> last;
1.23
1.24 /** The number of element in this buffer.
1.25 */
1.26 - public int count;
1.27 + private int count;
1.28
1.29 /** Has a list been created from this buffer yet?
1.30 */
1.31 - public boolean shared;
1.32 + private boolean shared;
1.33
1.34 /** Create a new initially empty list buffer.
1.35 */
1.36 @@ -73,8 +74,8 @@
1.37 }
1.38
1.39 public final void clear() {
1.40 - this.elems = new List<A>(null,null);
1.41 - this.last = this.elems;
1.42 + this.elems = List.nil();
1.43 + this.last = null;
1.44 count = 0;
1.45 shared = false;
1.46 }
1.47 @@ -103,22 +104,23 @@
1.48 /** Copy list and sets last.
1.49 */
1.50 private void copy() {
1.51 - List<A> p = elems = new List<A>(elems.head, elems.tail);
1.52 - while (true) {
1.53 - List<A> tail = p.tail;
1.54 - if (tail == null) break;
1.55 - tail = new List<A>(tail.head, tail.tail);
1.56 - p.setTail(tail);
1.57 - p = tail;
1.58 + if (elems.nonEmpty()) {
1.59 + List<A> orig = elems;
1.60 +
1.61 + elems = last = List.<A>of(orig.head);
1.62 +
1.63 + while ((orig = orig.tail).nonEmpty()) {
1.64 + last.tail = List.<A>of(orig.head);
1.65 + last = last.tail;
1.66 + }
1.67 }
1.68 - last = p;
1.69 - shared = false;
1.70 }
1.71
1.72 /** Prepend an element to buffer.
1.73 */
1.74 public ListBuffer<A> prepend(A x) {
1.75 elems = elems.prepend(x);
1.76 + if (last == null) last = elems;
1.77 count++;
1.78 return this;
1.79 }
1.80 @@ -128,9 +130,13 @@
1.81 public ListBuffer<A> append(A x) {
1.82 x.getClass(); // null check
1.83 if (shared) copy();
1.84 - last.head = x;
1.85 - last.setTail(new List<A>(null,null));
1.86 - last = last.tail;
1.87 + List<A> newLast = List.<A>of(x);
1.88 + if (last != null) {
1.89 + last.tail = newLast;
1.90 + last = newLast;
1.91 + } else {
1.92 + elems = last = newLast;
1.93 + }
1.94 count++;
1.95 return this;
1.96 }
1.97 @@ -192,8 +198,9 @@
1.98 */
1.99 public A next() {
1.100 A x = elems.head;
1.101 - if (elems != last) {
1.102 + if (!elems.isEmpty()) {
1.103 elems = elems.tail;
1.104 + if (elems.isEmpty()) last = null;
1.105 count--;
1.106 }
1.107 return x;
1.108 @@ -205,10 +212,10 @@
1.109 return new Iterator<A>() {
1.110 List<A> elems = ListBuffer.this.elems;
1.111 public boolean hasNext() {
1.112 - return elems != last;
1.113 + return !elems.isEmpty();
1.114 }
1.115 public A next() {
1.116 - if (elems == last)
1.117 + if (elems.isEmpty())
1.118 throw new NoSuchElementException();
1.119 A elem = elems.head;
1.120 elems = elems.tail;
1.121 @@ -263,4 +270,8 @@
1.122 public A peek() {
1.123 return first();
1.124 }
1.125 +
1.126 + public A last() {
1.127 + return last != null ? last.head : null;
1.128 + }
1.129 }
