| /* |
| * Copyright 1999-2008 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| package com.sun.tools.javac.util; |
| |
| import java.util.AbstractQueue; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| /** A class for constructing lists by appending elements. Modelled after |
| * java.lang.StringBuffer. |
| * |
| * <p><b>This is NOT part of any API supported by Sun Microsystems. If |
| * you write code that depends on this, you do so at your own risk. |
| * This code and its internal interfaces are subject to change or |
| * deletion without notice.</b> |
| */ |
| public class ListBuffer<A> extends AbstractQueue<A> { |
| |
| public static <T> ListBuffer<T> lb() { |
| return new ListBuffer<T>(); |
| } |
| |
| public static <T> ListBuffer<T> of(T x) { |
| ListBuffer<T> lb = new ListBuffer<T>(); |
| lb.add(x); |
| return lb; |
| } |
| |
| /** The list of elements of this buffer. |
| */ |
| public List<A> elems; |
| |
| /** A pointer pointing to the last, sentinel element of `elems'. |
| */ |
| public List<A> last; |
| |
| /** The number of element in this buffer. |
| */ |
| public int count; |
| |
| /** Has a list been created from this buffer yet? |
| */ |
| public boolean shared; |
| |
| /** Create a new initially empty list buffer. |
| */ |
| public ListBuffer() { |
| clear(); |
| } |
| |
| public final void clear() { |
| this.elems = new List<A>(null,null); |
| this.last = this.elems; |
| count = 0; |
| shared = false; |
| } |
| |
| /** Return the number of elements in this buffer. |
| */ |
| public int length() { |
| return count; |
| } |
| public int size() { |
| return count; |
| } |
| |
| /** Is buffer empty? |
| */ |
| public boolean isEmpty() { |
| return count == 0; |
| } |
| |
| /** Is buffer not empty? |
| */ |
| public boolean nonEmpty() { |
| return count != 0; |
| } |
| |
| /** Copy list and sets last. |
| */ |
| private void copy() { |
| List<A> p = elems = new List<A>(elems.head, elems.tail); |
| while (true) { |
| List<A> tail = p.tail; |
| if (tail == null) break; |
| tail = new List<A>(tail.head, tail.tail); |
| p.setTail(tail); |
| p = tail; |
| } |
| last = p; |
| shared = false; |
| } |
| |
| /** Prepend an element to buffer. |
| */ |
| public ListBuffer<A> prepend(A x) { |
| elems = elems.prepend(x); |
| count++; |
| return this; |
| } |
| |
| /** Append an element to buffer. |
| */ |
| public ListBuffer<A> append(A x) { |
| x.getClass(); // null check |
| if (shared) copy(); |
| last.head = x; |
| last.setTail(new List<A>(null,null)); |
| last = last.tail; |
| count++; |
| return this; |
| } |
| |
| /** Append all elements in a list to buffer. |
| */ |
| public ListBuffer<A> appendList(List<A> xs) { |
| while (xs.nonEmpty()) { |
| append(xs.head); |
| xs = xs.tail; |
| } |
| return this; |
| } |
| |
| /** Append all elements in a list to buffer. |
| */ |
| public ListBuffer<A> appendList(ListBuffer<A> xs) { |
| return appendList(xs.toList()); |
| } |
| |
| /** Append all elements in an array to buffer. |
| */ |
| public ListBuffer<A> appendArray(A[] xs) { |
| for (int i = 0; i < xs.length; i++) { |
| append(xs[i]); |
| } |
| return this; |
| } |
| |
| /** Convert buffer to a list of all its elements. |
| */ |
| public List<A> toList() { |
| shared = true; |
| return elems; |
| } |
| |
| /** Does the list contain the specified element? |
| */ |
| public boolean contains(Object x) { |
| return elems.contains(x); |
| } |
| |
| /** Convert buffer to an array |
| */ |
| public <T> T[] toArray(T[] vec) { |
| return elems.toArray(vec); |
| } |
| public Object[] toArray() { |
| return toArray(new Object[size()]); |
| } |
| |
| /** The first element in this buffer. |
| */ |
| public A first() { |
| return elems.head; |
| } |
| |
| /** Return first element in this buffer and remove |
| */ |
| public A next() { |
| A x = elems.head; |
| if (elems != last) { |
| elems = elems.tail; |
| count--; |
| } |
| return x; |
| } |
| |
| /** An enumeration of all elements in this buffer. |
| */ |
| public Iterator<A> iterator() { |
| return new Iterator<A>() { |
| List<A> elems = ListBuffer.this.elems; |
| public boolean hasNext() { |
| return elems != last; |
| } |
| public A next() { |
| if (elems == last) |
| throw new NoSuchElementException(); |
| A elem = elems.head; |
| elems = elems.tail; |
| return elem; |
| } |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| |
| public boolean add(A a) { |
| append(a); |
| return true; |
| } |
| |
| public boolean remove(Object o) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean containsAll(Collection<?> c) { |
| for (Object x: c) { |
| if (!contains(x)) |
| return false; |
| } |
| return true; |
| } |
| |
| public boolean addAll(Collection<? extends A> c) { |
| for (A a: c) |
| append(a); |
| return true; |
| } |
| |
| public boolean removeAll(Collection<?> c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean retainAll(Collection<?> c) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean offer(A a) { |
| append(a); |
| return true; |
| } |
| |
| public A poll() { |
| return next(); |
| } |
| |
| public A peek() { |
| return first(); |
| } |
| } |