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src/java.base/share/classes/java/util/AbstractList.java
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rev 13796 : imported patch 8079136-Nested-SubLists
@@ -1,7 +1,7 @@
/*
- * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. 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. Oracle designates this
@@ -460,14 +460,13 @@
* {@inheritDoc}
*
* @implSpec
* This implementation returns a list that subclasses
* {@code AbstractList}. The subclass stores, in private fields, the
- * offset of the subList within the backing list, the size of the subList
- * (which can change over its lifetime), and the expected
- * {@code modCount} value of the backing list. There are two variants
- * of the subclass, one of which implements {@code RandomAccess}.
+ * size of the subList (which can change over its lifetime), and the
+ * expected {@code modCount} value of the backing list. There are two
+ * variants of the subclass, one of which implements {@code RandomAccess}.
* If this list implements {@code RandomAccess} the returned list will
* be an instance of the subclass that implements {@code RandomAccess}.
*
* <p>The subclass's {@code set(int, E)}, {@code get(int)},
* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int,
@@ -491,15 +490,26 @@
* {@code (fromIndex < 0 || toIndex > size)}
* @throws IllegalArgumentException if the endpoint indices are out of order
* {@code (fromIndex > toIndex)}
*/
public List<E> subList(int fromIndex, int toIndex) {
+ subListRangeCheck(fromIndex, toIndex, size());
return (this instanceof RandomAccess ?
new RandomAccessSubList<>(this, fromIndex, toIndex) :
new SubList<>(this, fromIndex, toIndex));
}
+ static void subListRangeCheck(int fromIndex, int toIndex, int size) {
+ if (fromIndex < 0)
+ throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
+ if (toIndex > size)
+ throw new IndexOutOfBoundsException("toIndex = " + toIndex);
+ if (fromIndex > toIndex)
+ throw new IllegalArgumentException("fromIndex(" + fromIndex +
+ ") > toIndex(" + toIndex + ")");
+ }
+
// Comparison and hashing
/**
* Compares the specified object with this list for equality. Returns
* {@code true} if and only if the specified object is also a list, both
@@ -621,70 +631,76 @@
}
private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+size();
}
-}
-class SubList<E> extends AbstractList<E> {
- private final AbstractList<E> l;
+ private static class SubList<E> extends AbstractList<E> {
+ private final AbstractList<E> root;
+ private final SubList<E> parent;
private final int offset;
- private int size;
+ protected int size;
- SubList(AbstractList<E> list, int fromIndex, int toIndex) {
- if (fromIndex < 0)
- throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
- if (toIndex > list.size())
- throw new IndexOutOfBoundsException("toIndex = " + toIndex);
- if (fromIndex > toIndex)
- throw new IllegalArgumentException("fromIndex(" + fromIndex +
- ") > toIndex(" + toIndex + ")");
- l = list;
- offset = fromIndex;
- size = toIndex - fromIndex;
- this.modCount = l.modCount;
+ /**
+ * Constructs a sublist of an arbitrary AbstractList, which is
+ * not a SubList itself.
+ */
+ public SubList(AbstractList<E> root, int fromIndex, int toIndex) {
+ this.root = root;
+ this.parent = null;
+ this.offset = fromIndex;
+ this.size = toIndex - fromIndex;
+ this.modCount = root.modCount;
+ }
+
+ /**
+ * Constructs a sublist of another SubList.
+ */
+ protected SubList(SubList<E> parent, int fromIndex, int toIndex) {
+ this.root = parent.root;
+ this.parent = parent;
+ this.offset = parent.offset + fromIndex;
+ this.size = toIndex - fromIndex;
+ this.modCount = root.modCount;
}
public E set(int index, E element) {
- rangeCheck(index);
+ Objects.checkIndex(index, size);
checkForComodification();
- return l.set(index+offset, element);
+ return root.set(offset + index, element);
}
public E get(int index) {
- rangeCheck(index);
+ Objects.checkIndex(index, size);
checkForComodification();
- return l.get(index+offset);
+ return root.get(offset + index);
}
public int size() {
checkForComodification();
return size;
}
public void add(int index, E element) {
rangeCheckForAdd(index);
checkForComodification();
- l.add(index+offset, element);
- this.modCount = l.modCount;
- size++;
+ root.add(offset + index, element);
+ updateSizeAndModCount(1);
}
public E remove(int index) {
- rangeCheck(index);
+ Objects.checkIndex(index, size);
checkForComodification();
- E result = l.remove(index+offset);
- this.modCount = l.modCount;
- size--;
+ E result = root.remove(offset + index);
+ updateSizeAndModCount(-1);
return result;
}
protected void removeRange(int fromIndex, int toIndex) {
checkForComodification();
- l.removeRange(fromIndex+offset, toIndex+offset);
- this.modCount = l.modCount;
- size -= (toIndex-fromIndex);
+ root.removeRange(offset + fromIndex, offset + toIndex);
+ updateSizeAndModCount(fromIndex - toIndex);
}
public boolean addAll(Collection<? extends E> c) {
return addAll(size, c);
}
@@ -692,28 +708,27 @@
public boolean addAll(int index, Collection<? extends E> c) {
rangeCheckForAdd(index);
int cSize = c.size();
if (cSize==0)
return false;
-
checkForComodification();
- l.addAll(offset+index, c);
- this.modCount = l.modCount;
- size += cSize;
+ root.addAll(offset + index, c);
+ updateSizeAndModCount(cSize);
return true;
}
public Iterator<E> iterator() {
return listIterator();
}
- public ListIterator<E> listIterator(final int index) {
+ public ListIterator<E> listIterator(int index) {
checkForComodification();
rangeCheckForAdd(index);
return new ListIterator<E>() {
- private final ListIterator<E> i = l.listIterator(index+offset);
+ private final ListIterator<E> i =
+ root.listIterator(offset + index);
public boolean hasNext() {
return nextIndex() < size;
}
@@ -743,54 +758,74 @@
return i.previousIndex() - offset;
}
public void remove() {
i.remove();
- SubList.this.modCount = l.modCount;
- size--;
+ updateSizeAndModCount(-1);
}
public void set(E e) {
i.set(e);
}
public void add(E e) {
i.add(e);
- SubList.this.modCount = l.modCount;
- size++;
+ updateSizeAndModCount(1);
}
};
}
public List<E> subList(int fromIndex, int toIndex) {
+ subListRangeCheck(fromIndex, toIndex, size);
return new SubList<>(this, fromIndex, toIndex);
}
- private void rangeCheck(int index) {
- if (index < 0 || index >= size)
- throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
- }
-
private void rangeCheckForAdd(int index) {
if (index < 0 || index > size)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+size;
}
private void checkForComodification() {
- if (this.modCount != l.modCount)
+ if (root.modCount != this.modCount)
throw new ConcurrentModificationException();
}
-}
-class RandomAccessSubList<E> extends SubList<E> implements RandomAccess {
- RandomAccessSubList(AbstractList<E> list, int fromIndex, int toIndex) {
- super(list, fromIndex, toIndex);
+ private void updateSizeAndModCount(int sizeChange) {
+ SubList<E> slist = this;
+ do {
+ slist.size += sizeChange;
+ slist.modCount = root.modCount;
+ slist = slist.parent;
+ } while (slist != null);
+ }
+ }
+
+ private static class RandomAccessSubList<E>
+ extends SubList<E> implements RandomAccess {
+
+ /**
+ * Constructs a sublist of an arbitrary AbstractList, which is
+ * not a RandomAccessSubList itself.
+ */
+ RandomAccessSubList(AbstractList<E> root,
+ int fromIndex, int toIndex) {
+ super(root, fromIndex, toIndex);
+ }
+
+ /**
+ * Constructs a sublist of another RandomAccessSubList.
+ */
+ RandomAccessSubList(RandomAccessSubList<E> parent,
+ int fromIndex, int toIndex) {
+ super(parent, fromIndex, toIndex);
}
public List<E> subList(int fromIndex, int toIndex) {
+ subListRangeCheck(fromIndex, toIndex, size);
return new RandomAccessSubList<>(this, fromIndex, toIndex);
}
+ }
}
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