| /* |
| * Copyright 1999-2006 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.lang.reflect.Array; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.AbstractCollection; |
| import java.util.ListIterator; |
| import java.util.NoSuchElementException; |
| |
| /** A class for generic linked lists. Links are supposed to be |
| * immutable, the only exception being the incremental construction of |
| * lists via ListBuffers. List is the main container class in |
| * GJC. Most data structures and algorthms in GJC use lists rather |
| * than arrays. |
| * |
| * <p>Lists are always trailed by a sentinel element, whose head and tail |
| * are both null. |
| * |
| * <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 List<A> extends AbstractCollection<A> implements java.util.List<A> { |
| |
| /** The first element of the list, supposed to be immutable. |
| */ |
| public A head; |
| |
| /** The remainder of the list except for its first element, supposed |
| * to be immutable. |
| */ |
| //@Deprecated |
| public List<A> tail; |
| |
| /** Construct a list given its head and tail. |
| */ |
| List(A head, List<A> tail) { |
| this.tail = tail; |
| this.head = head; |
| } |
| |
| /** Construct an empty list. |
| */ |
| @SuppressWarnings("unchecked") |
| public static <A> List<A> nil() { |
| return EMPTY_LIST; |
| } |
| private static List EMPTY_LIST = new List<Object>(null,null) { |
| public List<Object> setTail(List<Object> tail) { |
| throw new UnsupportedOperationException(); |
| } |
| public boolean isEmpty() { |
| return true; |
| } |
| }; |
| |
| /** Construct a list consisting of given element. |
| */ |
| public static <A> List<A> of(A x1) { |
| return new List<A>(x1, List.<A>nil()); |
| } |
| |
| /** Construct a list consisting of given elements. |
| */ |
| public static <A> List<A> of(A x1, A x2) { |
| return new List<A>(x1, of(x2)); |
| } |
| |
| /** Construct a list consisting of given elements. |
| */ |
| public static <A> List<A> of(A x1, A x2, A x3) { |
| return new List<A>(x1, of(x2, x3)); |
| } |
| |
| /** Construct a list consisting of given elements. |
| */ |
| public static <A> List<A> of(A x1, A x2, A x3, A... rest) { |
| return new List<A>(x1, new List<A>(x2, new List<A>(x3, from(rest)))); |
| } |
| |
| /** |
| * Construct a list consisting all elements of given array. |
| * @param array an array; if {@code null} return an empty list |
| */ |
| public static <A> List<A> from(A[] array) { |
| List<A> xs = nil(); |
| if (array != null) |
| for (int i = array.length - 1; i >= 0; i--) |
| xs = new List<A>(array[i], xs); |
| return xs; |
| } |
| |
| /** Construct a list consisting of a given number of identical elements. |
| * @param len The number of elements in the list. |
| * @param init The value of each element. |
| */ |
| @Deprecated |
| public static <A> List<A> fill(int len, A init) { |
| List<A> l = nil(); |
| for (int i = 0; i < len; i++) l = new List<A>(init, l); |
| return l; |
| } |
| |
| /** Does list have no elements? |
| */ |
| @Override |
| public boolean isEmpty() { |
| return tail == null; |
| } |
| |
| /** Does list have elements? |
| */ |
| //@Deprecated |
| public boolean nonEmpty() { |
| return tail != null; |
| } |
| |
| /** Return the number of elements in this list. |
| */ |
| //@Deprecated |
| public int length() { |
| List<A> l = this; |
| int len = 0; |
| while (l.tail != null) { |
| l = l.tail; |
| len++; |
| } |
| return len; |
| } |
| @Override |
| public int size() { |
| return length(); |
| } |
| |
| public List<A> setTail(List<A> tail) { |
| this.tail = tail; |
| return tail; |
| } |
| |
| /** Prepend given element to front of list, forming and returning |
| * a new list. |
| */ |
| public List<A> prepend(A x) { |
| return new List<A>(x, this); |
| } |
| |
| /** Prepend given list of elements to front of list, forming and returning |
| * a new list. |
| */ |
| public List<A> prependList(List<A> xs) { |
| if (this.isEmpty()) return xs; |
| if (xs.isEmpty()) return this; |
| if (xs.tail.isEmpty()) return prepend(xs.head); |
| // return this.prependList(xs.tail).prepend(xs.head); |
| List<A> result = this; |
| List<A> rev = xs.reverse(); |
| assert rev != xs; |
| // since xs.reverse() returned a new list, we can reuse the |
| // individual List objects, instead of allocating new ones. |
| while (rev.nonEmpty()) { |
| List<A> h = rev; |
| rev = rev.tail; |
| h.setTail(result); |
| result = h; |
| } |
| return result; |
| } |
| |
| /** Reverse list. |
| * If the list is empty or a singleton, then the same list is returned. |
| * Otherwise a new list is formed. |
| */ |
| public List<A> reverse() { |
| // if it is empty or a singleton, return itself |
| if (isEmpty() || tail.isEmpty()) |
| return this; |
| |
| List<A> rev = nil(); |
| for (List<A> l = this; l.nonEmpty(); l = l.tail) |
| rev = new List<A>(l.head, rev); |
| return rev; |
| } |
| |
| /** Append given element at length, forming and returning |
| * a new list. |
| */ |
| public List<A> append(A x) { |
| return of(x).prependList(this); |
| } |
| |
| /** Append given list at length, forming and returning |
| * a new list. |
| */ |
| public List<A> appendList(List<A> x) { |
| return x.prependList(this); |
| } |
| |
| /** |
| * Append given list buffer at length, forming and returning a new |
| * list. |
| */ |
| public List<A> appendList(ListBuffer<A> x) { |
| return appendList(x.toList()); |
| } |
| |
| /** Copy successive elements of this list into given vector until |
| * list is exhausted or end of vector is reached. |
| */ |
| @Override @SuppressWarnings("unchecked") |
| public <T> T[] toArray(T[] vec) { |
| int i = 0; |
| List<A> l = this; |
| Object[] dest = vec; |
| while (l.nonEmpty() && i < vec.length) { |
| dest[i] = l.head; |
| l = l.tail; |
| i++; |
| } |
| if (l.isEmpty()) { |
| if (i < vec.length) |
| vec[i] = null; |
| return vec; |
| } |
| |
| vec = (T[])Array.newInstance(vec.getClass().getComponentType(), size()); |
| return toArray(vec); |
| } |
| |
| public Object[] toArray() { |
| return toArray(new Object[size()]); |
| } |
| |
| /** Form a string listing all elements with given separator character. |
| */ |
| public String toString(String sep) { |
| if (isEmpty()) { |
| return ""; |
| } else { |
| StringBuffer buf = new StringBuffer(); |
| buf.append(head); |
| for (List<A> l = tail; l.nonEmpty(); l = l.tail) { |
| buf.append(sep); |
| buf.append(l.head); |
| } |
| return buf.toString(); |
| } |
| } |
| |
| /** Form a string listing all elements with comma as the separator character. |
| */ |
| @Override |
| public String toString() { |
| return toString(","); |
| } |
| |
| /** Compute a hash code, overrides Object |
| * @see java.util.List#hashCode |
| */ |
| @Override |
| public int hashCode() { |
| List<A> l = this; |
| int h = 1; |
| while (l.tail != null) { |
| h = h * 31 + (l.head == null ? 0 : l.head.hashCode()); |
| l = l.tail; |
| } |
| return h; |
| } |
| |
| /** Is this list the same as other list? |
| * @see java.util.List#equals |
| */ |
| @Override |
| public boolean equals(Object other) { |
| if (other instanceof List<?>) |
| return equals(this, (List<?>)other); |
| if (other instanceof java.util.List<?>) { |
| List<A> t = this; |
| Iterator<?> oIter = ((java.util.List<?>) other).iterator(); |
| while (t.tail != null && oIter.hasNext()) { |
| Object o = oIter.next(); |
| if ( !(t.head == null ? o == null : t.head.equals(o))) |
| return false; |
| t = t.tail; |
| } |
| return (t.isEmpty() && !oIter.hasNext()); |
| } |
| return false; |
| } |
| |
| /** Are the two lists the same? |
| */ |
| public static boolean equals(List xs, List ys) { |
| while (xs.tail != null && ys.tail != null) { |
| if (xs.head == null) { |
| if (ys.head != null) return false; |
| } else { |
| if (!xs.head.equals(ys.head)) return false; |
| } |
| xs = xs.tail; |
| ys = ys.tail; |
| } |
| return xs.tail == null && ys.tail == null; |
| } |
| |
| /** Does the list contain the specified element? |
| */ |
| @Override |
| public boolean contains(Object x) { |
| List<A> l = this; |
| while (l.tail != null) { |
| if (x == null) { |
| if (l.head == null) return true; |
| } else { |
| if (l.head.equals(x)) return true; |
| } |
| l = l.tail; |
| } |
| return false; |
| } |
| |
| /** The last element in the list, if any, or null. |
| */ |
| public A last() { |
| A last = null; |
| List<A> t = this; |
| while (t.tail != null) { |
| last = t.head; |
| t = t.tail; |
| } |
| return last; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public static <T> List<T> convert(Class<T> klass, List<?> list) { |
| if (list == null) |
| return null; |
| for (Object o : list) |
| klass.cast(o); |
| return (List<T>)list; |
| } |
| |
| private static Iterator EMPTYITERATOR = new Iterator() { |
| public boolean hasNext() { |
| return false; |
| } |
| public Object next() { |
| throw new java.util.NoSuchElementException(); |
| } |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| |
| @SuppressWarnings("unchecked") |
| private static <A> Iterator<A> emptyIterator() { |
| return EMPTYITERATOR; |
| } |
| |
| @Override |
| public Iterator<A> iterator() { |
| if (tail == null) |
| return emptyIterator(); |
| return new Iterator<A>() { |
| List<A> elems = List.this; |
| public boolean hasNext() { |
| return elems.tail != null; |
| } |
| public A next() { |
| if (elems.tail == null) |
| throw new NoSuchElementException(); |
| A result = elems.head; |
| elems = elems.tail; |
| return result; |
| } |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| |
| public A get(int index) { |
| if (index < 0) |
| throw new IndexOutOfBoundsException(String.valueOf(index)); |
| |
| List<A> l = this; |
| for (int i = index; i-- > 0 && !l.isEmpty(); l = l.tail) |
| ; |
| |
| if (l.isEmpty()) |
| throw new IndexOutOfBoundsException("Index: " + index + ", " + |
| "Size: " + size()); |
| return l.head; |
| } |
| |
| public boolean addAll(int index, Collection<? extends A> c) { |
| if (c.isEmpty()) |
| return false; |
| throw new UnsupportedOperationException(); |
| } |
| |
| public A set(int index, A element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void add(int index, A element) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public A remove(int index) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public int indexOf(Object o) { |
| int i = 0; |
| for (List<A> l = this; l.tail != null; l = l.tail, i++) { |
| if (l.head == null ? o == null : l.head.equals(o)) |
| return i; |
| } |
| return -1; |
| } |
| |
| public int lastIndexOf(Object o) { |
| int last = -1; |
| int i = 0; |
| for (List<A> l = this; l.tail != null; l = l.tail, i++) { |
| if (l.head == null ? o == null : l.head.equals(o)) |
| last = i; |
| } |
| return last; |
| } |
| |
| public ListIterator<A> listIterator() { |
| return Collections.unmodifiableList(new ArrayList<A>(this)).listIterator(); |
| } |
| |
| public ListIterator<A> listIterator(int index) { |
| return Collections.unmodifiableList(new ArrayList<A>(this)).listIterator(index); |
| } |
| |
| public java.util.List<A> subList(int fromIndex, int toIndex) { |
| if (fromIndex < 0 || toIndex > size() || fromIndex > toIndex) |
| throw new IllegalArgumentException(); |
| |
| ArrayList<A> a = new ArrayList<A>(toIndex - fromIndex); |
| int i = 0; |
| for (List<A> l = this; l.tail != null; l = l.tail, i++) { |
| if (i == toIndex) |
| break; |
| if (i >= fromIndex) |
| a.add(l.head); |
| } |
| |
| return Collections.unmodifiableList(a); |
| } |
| } |