--- jsr166/src/main/java/util/ArrayList.java 2016/11/13 02:10:09 1.39
+++ jsr166/src/main/java/util/ArrayList.java 2017/05/06 06:49:45 1.50
@@ -91,7 +91,7 @@ import java.util.function.UnaryOperator;
* should be used only to detect bugs.
*
*
This class is a member of the
- *
+ *
* Java Collections Framework.
*
* @param the type of elements in this list
@@ -501,6 +501,7 @@ public class ArrayList extends Abstra
s - index);
elementData[index] = element;
size = s + 1;
+ // checkInvariants();
}
/**
@@ -524,6 +525,7 @@ public class ArrayList extends Abstra
numMoved);
elementData[--size] = null; // clear to let GC do its work
+ // checkInvariants();
return oldValue;
}
@@ -557,7 +559,7 @@ public class ArrayList extends Abstra
return false;
}
- /*
+ /**
* Private remove method that skips bounds checking and does not
* return the value removed.
*/
@@ -576,12 +578,9 @@ public class ArrayList extends Abstra
*/
public void clear() {
modCount++;
-
- // clear to let GC do its work
- for (int i = 0; i < size; i++)
- elementData[i] = null;
-
- size = 0;
+ final Object[] es = elementData;
+ for (int to = size, i = size = 0; i < to; i++)
+ es[i] = null;
}
/**
@@ -609,6 +608,7 @@ public class ArrayList extends Abstra
elementData = grow(s + numNew);
System.arraycopy(a, 0, elementData, s, numNew);
size = s + numNew;
+ // checkInvariants();
return true;
}
@@ -647,6 +647,7 @@ public class ArrayList extends Abstra
numMoved);
System.arraycopy(a, 0, elementData, index, numNew);
size = s + numNew;
+ // checkInvariants();
return true;
}
@@ -669,16 +670,15 @@ public class ArrayList extends Abstra
outOfBoundsMsg(fromIndex, toIndex));
}
modCount++;
- int numMoved = size - toIndex;
- System.arraycopy(elementData, toIndex, elementData, fromIndex,
- numMoved);
-
- // clear to let GC do its work
- int newSize = size - (toIndex-fromIndex);
- for (int i = newSize; i < size; i++) {
- elementData[i] = null;
- }
- size = newSize;
+ shiftTailOverGap(elementData, fromIndex, toIndex);
+ // checkInvariants();
+ }
+
+ /** Erases the gap from lo to hi, by sliding down following elements. */
+ private void shiftTailOverGap(Object[] es, int lo, int hi) {
+ System.arraycopy(es, hi, es, lo, size - hi);
+ for (int to = size, i = (size -= hi - lo); i < to; i++)
+ es[i] = null;
}
/**
@@ -721,7 +721,7 @@ public class ArrayList extends Abstra
* @see Collection#contains(Object)
*/
public boolean removeAll(Collection> c) {
- return batchRemove(c, false);
+ return batchRemove(c, false, 0, size);
}
/**
@@ -741,17 +741,17 @@ public class ArrayList extends Abstra
* @see Collection#contains(Object)
*/
public boolean retainAll(Collection> c) {
- return batchRemove(c, true);
+ return batchRemove(c, true, 0, size);
}
- private boolean batchRemove(Collection> c, boolean complement) {
+ boolean batchRemove(Collection> c, boolean complement,
+ final int from, final int end) {
Objects.requireNonNull(c);
final Object[] es = elementData;
- final int end = size;
final boolean modified;
int r;
// Optimize for initial run of survivors
- for (r = 0; r < end && c.contains(es[r]) == complement; r++)
+ for (r = from; r < end && c.contains(es[r]) == complement; r++)
;
if (modified = (r < end)) {
int w = r++;
@@ -767,22 +767,25 @@ public class ArrayList extends Abstra
throw ex;
} finally {
modCount += end - w;
- Arrays.fill(es, size = w, end, null);
+ shiftTailOverGap(es, w, end);
}
}
+ // checkInvariants();
return modified;
}
/**
- * Save the state of the {@code ArrayList} instance to a stream (that
- * is, serialize it).
+ * Saves the state of the {@code ArrayList} instance to a stream
+ * (that is, serializes it).
*
+ * @param s the stream
+ * @throws java.io.IOException if an I/O error occurs
* @serialData The length of the array backing the {@code ArrayList}
* instance is emitted (int), followed by all of its elements
* (each an {@code Object}) in the proper order.
*/
private void writeObject(java.io.ObjectOutputStream s)
- throws java.io.IOException{
+ throws java.io.IOException {
// Write out element count, and any hidden stuff
int expectedModCount = modCount;
s.defaultWriteObject();
@@ -801,8 +804,12 @@ public class ArrayList extends Abstra
}
/**
- * Reconstitute the {@code ArrayList} instance from a stream (that is,
- * deserialize it).
+ * Reconstitutes the {@code ArrayList} instance from a stream (that is,
+ * deserializes it).
+ * @param s the stream
+ * @throws ClassNotFoundException if the class of a serialized object
+ * could not be found
+ * @throws java.io.IOException if an I/O error occurs
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
@@ -914,25 +921,21 @@ public class ArrayList extends Abstra
}
@Override
- @SuppressWarnings("unchecked")
- public void forEachRemaining(Consumer super E> consumer) {
- Objects.requireNonNull(consumer);
+ public void forEachRemaining(Consumer super E> action) {
+ Objects.requireNonNull(action);
final int size = ArrayList.this.size;
int i = cursor;
- if (i >= size) {
- return;
- }
- final Object[] elementData = ArrayList.this.elementData;
- if (i >= elementData.length) {
- throw new ConcurrentModificationException();
- }
- while (i != size && modCount == expectedModCount) {
- consumer.accept((E) elementData[i++]);
+ if (i < size) {
+ final Object[] es = elementData;
+ if (i >= es.length)
+ throw new ConcurrentModificationException();
+ for (; i < size && modCount == expectedModCount; i++)
+ action.accept(elementAt(es, i));
+ // update once at end to reduce heap write traffic
+ cursor = i;
+ lastRet = i - 1;
+ checkForComodification();
}
- // update once at end of iteration to reduce heap write traffic
- cursor = i;
- lastRet = i - 1;
- checkForComodification();
}
final void checkForComodification() {
@@ -1119,6 +1122,33 @@ public class ArrayList extends Abstra
return true;
}
+ public boolean removeAll(Collection> c) {
+ return batchRemove(c, false);
+ }
+
+ public boolean retainAll(Collection> c) {
+ return batchRemove(c, true);
+ }
+
+ private boolean batchRemove(Collection> c, boolean complement) {
+ checkForComodification();
+ int oldSize = root.size;
+ boolean modified =
+ root.batchRemove(c, complement, offset, offset + size);
+ if (modified)
+ updateSizeAndModCount(root.size - oldSize);
+ return modified;
+ }
+
+ public boolean removeIf(Predicate super E> filter) {
+ checkForComodification();
+ int oldSize = root.size;
+ boolean modified = root.removeIf(filter, offset, offset + size);
+ if (modified)
+ updateSizeAndModCount(root.size - oldSize);
+ return modified;
+ }
+
public Iterator iterator() {
return listIterator();
}
@@ -1166,24 +1196,21 @@ public class ArrayList extends Abstra
return (E) elementData[offset + (lastRet = i)];
}
- @SuppressWarnings("unchecked")
- public void forEachRemaining(Consumer super E> consumer) {
- Objects.requireNonNull(consumer);
+ public void forEachRemaining(Consumer super E> action) {
+ Objects.requireNonNull(action);
final int size = SubList.this.size;
int i = cursor;
- if (i >= size) {
- return;
- }
- final Object[] elementData = root.elementData;
- if (offset + i >= elementData.length) {
- throw new ConcurrentModificationException();
- }
- while (i != size && modCount == expectedModCount) {
- consumer.accept((E) elementData[offset + (i++)]);
+ if (i < size) {
+ final Object[] es = root.elementData;
+ if (offset + i >= es.length)
+ throw new ConcurrentModificationException();
+ for (; i < size && modCount == expectedModCount; i++)
+ action.accept(elementAt(es, offset + i));
+ // update once at end to reduce heap write traffic
+ cursor = i;
+ lastRet = i - 1;
+ checkForComodification();
}
- // update once at end of iteration to reduce heap write traffic
- lastRet = cursor = i;
- checkForComodification();
}
public int nextIndex() {
@@ -1273,9 +1300,8 @@ public class ArrayList extends Abstra
public Spliterator spliterator() {
checkForComodification();
- // ArrayListSpliterator is not used because late-binding logic
- // is different here
- return new Spliterator<>() {
+ // ArrayListSpliterator not used here due to late-binding
+ return new Spliterator() {
private int index = offset; // current index, modified on advance/split
private int fence = -1; // -1 until used; then one past last index
private int expectedModCount; // initialized when fence set
@@ -1289,12 +1315,11 @@ public class ArrayList extends Abstra
return hi;
}
- public ArrayListSpliterator trySplit() {
+ public ArrayList.ArrayListSpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
- // ArrayListSpliterator could be used here as the source is already bound
+ // ArrayListSpliterator can be used here as the source is already bound
return (lo >= mid) ? null : // divide range in half unless too small
- new ArrayListSpliterator<>(root, lo, index = mid,
- expectedModCount);
+ root.new ArrayListSpliterator(lo, index = mid, expectedModCount);
}
public boolean tryAdvance(Consumer super E> action) {
@@ -1336,7 +1361,7 @@ public class ArrayList extends Abstra
}
public long estimateSize() {
- return (long) (getFence() - index);
+ return getFence() - index;
}
public int characteristics() {
@@ -1346,18 +1371,19 @@ public class ArrayList extends Abstra
}
}
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
@Override
public void forEach(Consumer super E> action) {
Objects.requireNonNull(action);
final int expectedModCount = modCount;
final Object[] es = elementData;
final int size = this.size;
- for (int i = 0; modCount == expectedModCount && i < size; i++) {
+ for (int i = 0; modCount == expectedModCount && i < size; i++)
action.accept(elementAt(es, i));
- }
- if (modCount != expectedModCount) {
+ if (modCount != expectedModCount)
throw new ConcurrentModificationException();
- }
}
/**
@@ -1375,11 +1401,11 @@ public class ArrayList extends Abstra
*/
@Override
public Spliterator spliterator() {
- return new ArrayListSpliterator<>(this, 0, -1, 0);
+ return new ArrayListSpliterator(0, -1, 0);
}
/** Index-based split-by-two, lazily initialized Spliterator */
- static final class ArrayListSpliterator implements Spliterator {
+ final class ArrayListSpliterator implements Spliterator {
/*
* If ArrayLists were immutable, or structurally immutable (no
@@ -1413,15 +1439,12 @@ public class ArrayList extends Abstra
* these streamlinings.
*/
- private final ArrayList list;
private int index; // current index, modified on advance/split
private int fence; // -1 until used; then one past last index
private int expectedModCount; // initialized when fence set
- /** Create new spliterator covering the given range */
- ArrayListSpliterator(ArrayList list, int origin, int fence,
- int expectedModCount) {
- this.list = list; // OK if null unless traversed
+ /** Creates new spliterator covering the given range. */
+ ArrayListSpliterator(int origin, int fence, int expectedModCount) {
this.index = origin;
this.fence = fence;
this.expectedModCount = expectedModCount;
@@ -1429,23 +1452,17 @@ public class ArrayList extends Abstra
private int getFence() { // initialize fence to size on first use
int hi; // (a specialized variant appears in method forEach)
- ArrayList lst;
if ((hi = fence) < 0) {
- if ((lst = list) == null)
- hi = fence = 0;
- else {
- expectedModCount = lst.modCount;
- hi = fence = lst.size;
- }
+ expectedModCount = modCount;
+ hi = fence = size;
}
return hi;
}
- public ArrayListSpliterator trySplit() {
+ public ArrayListSpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid) ? null : // divide range in half unless too small
- new ArrayListSpliterator<>(list, lo, index = mid,
- expectedModCount);
+ new ArrayListSpliterator(lo, index = mid, expectedModCount);
}
public boolean tryAdvance(Consumer super E> action) {
@@ -1454,9 +1471,9 @@ public class ArrayList extends Abstra
int hi = getFence(), i = index;
if (i < hi) {
index = i + 1;
- @SuppressWarnings("unchecked") E e = (E)list.elementData[i];
+ @SuppressWarnings("unchecked") E e = (E)elementData[i];
action.accept(e);
- if (list.modCount != expectedModCount)
+ if (modCount != expectedModCount)
throw new ConcurrentModificationException();
return true;
}
@@ -1465,13 +1482,13 @@ public class ArrayList extends Abstra
public void forEachRemaining(Consumer super E> action) {
int i, hi, mc; // hoist accesses and checks from loop
- ArrayList lst; Object[] a;
+ Object[] a;
if (action == null)
throw new NullPointerException();
- if ((lst = list) != null && (a = lst.elementData) != null) {
+ if ((a = elementData) != null) {
if ((hi = fence) < 0) {
- mc = lst.modCount;
- hi = lst.size;
+ mc = modCount;
+ hi = size;
}
else
mc = expectedModCount;
@@ -1480,7 +1497,7 @@ public class ArrayList extends Abstra
@SuppressWarnings("unchecked") E e = (E) a[i];
action.accept(e);
}
- if (lst.modCount == mc)
+ if (modCount == mc)
return;
}
}
@@ -1488,7 +1505,7 @@ public class ArrayList extends Abstra
}
public long estimateSize() {
- return (long) (getFence() - index);
+ return getFence() - index;
}
public int characteristics() {
@@ -1508,38 +1525,52 @@ public class ArrayList extends Abstra
return (bits[i >> 6] & (1L << i)) == 0;
}
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
@Override
- public boolean removeIf(Predicate super E> filter) {
+ public boolean removeIf(Predicate super E> filter) {
+ return removeIf(filter, 0, size);
+ }
+
+ /**
+ * Removes all elements satisfying the given predicate, from index
+ * i (inclusive) to index end (exclusive).
+ */
+ boolean removeIf(Predicate super E> filter, int i, final int end) {
Objects.requireNonNull(filter);
int expectedModCount = modCount;
final Object[] es = elementData;
- final int end = size;
- final boolean modified;
- int i;
// Optimize for initial run of survivors
- for (i = 0; i < end && !filter.test(elementAt(es, i)); i++)
+ for (; i < end && !filter.test(elementAt(es, i)); i++)
;
// Tolerate predicates that reentrantly access the collection for
// read (but writers still get CME), so traverse once to find
// elements to delete, a second pass to physically expunge.
- if (modified = (i < end)) {
- expectedModCount++;
- modCount++;
+ if (i < end) {
final int beg = i;
final long[] deathRow = nBits(end - beg);
deathRow[0] = 1L; // set bit 0
for (i = beg + 1; i < end; i++)
if (filter.test(elementAt(es, i)))
setBit(deathRow, i - beg);
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ expectedModCount++;
+ modCount++;
int w = beg;
for (i = beg; i < end; i++)
if (isClear(deathRow, i - beg))
es[w++] = es[i];
- Arrays.fill(es, size = w, end, null);
+ shiftTailOverGap(es, w, end);
+ // checkInvariants();
+ return true;
+ } else {
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ // checkInvariants();
+ return false;
}
- if (modCount != expectedModCount)
- throw new ConcurrentModificationException();
- return modified;
}
@Override
@@ -1548,13 +1579,12 @@ public class ArrayList extends Abstra
final int expectedModCount = modCount;
final Object[] es = elementData;
final int size = this.size;
- for (int i=0; modCount == expectedModCount && i < size; i++) {
+ for (int i = 0; modCount == expectedModCount && i < size; i++)
es[i] = operator.apply(elementAt(es, i));
- }
- if (modCount != expectedModCount) {
+ if (modCount != expectedModCount)
throw new ConcurrentModificationException();
- }
modCount++;
+ // checkInvariants();
}
@Override
@@ -1562,9 +1592,14 @@ public class ArrayList extends Abstra
public void sort(Comparator super E> c) {
final int expectedModCount = modCount;
Arrays.sort((E[]) elementData, 0, size, c);
- if (modCount != expectedModCount) {
+ if (modCount != expectedModCount)
throw new ConcurrentModificationException();
- }
modCount++;
+ // checkInvariants();
+ }
+
+ void checkInvariants() {
+ // assert size >= 0;
+ // assert size == elementData.length || elementData[size] == null;
}
}