Java-ArrayList源码分析及示例

标签：arraylist

Integer value=null;
Iterator iter=list.iterator();
while(iter.hasNext())
{
    value=(Interger)iter.next();
}

Interger value=null;
int size=list.size();
fo(int i=0;i<size;i++)
{
    value=(Integer)list.get(i);
}

Integer value=null;
for(Integer inte : list)
{
    value=inte;
}

public class Hello {

public static void main(String[] args) {

        ArrayList list = new ArrayList();
list.add("1");
list.add("2");
list.add("3");
list.add("4");
list.add(0, "5");
System.out.println("the first element is: "+ list.get(0));
list.remove("3");
System.out.println("Arraylist size=: "+ list.size());
System.out.println("ArrayList contains 3 is: "+ list.contains(3));
list.set(1, "10");
        for(Iterator iter = list.iterator(); iter.hasNext(); )
        {
            System.out.println("next is: "+ iter.next());
}
        String[] arr = (String[])list.toArray(new String[0]);
        for (String str:arr)
            System.out.println("str: "+ str);
list.clear();
System.out.println("ArrayList is empty: "+ list.isEmpty());
}
}

public class ArrayList<E> extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, java.io.Serializable
{
private static final long serialVersionUID = 8683452581122892189L;  //序列化ID
private static final int DEFAULT_CAPACITY = 10; //初始大小为10，会动态增加
private static final Object[] EMPTY_ELEMENTDATA = {};//空的数组实例
private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};
    transient Object[] elementData; // ArrayList用来存储对象的数组
private int size;//数组中包含对象的个数
//ArrayList构造函数，构造初始大小的elementData
public ArrayList(int initialCapacity)
    {
if (initialCapacity > 0) {
this.elementData = new Object[initialCapacity];
} else if (initialCapacity == 0) {
this.elementData = EMPTY_ELEMENTDATA;
} else {
throw new IllegalArgumentException("Illegal Capacity: "+
                    initialCapacity);
}
    }
//构造函数，初始化大小为10的数组
public ArrayList() {
this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
}
//带有Collection的构造函数
public ArrayList(Collection<? extends E> c) {
elementData = c.toArray();
        if ((size = elementData.length) != 0) {
// c.toArray might (incorrectly) not return Object[] (see 6260652)
if (elementData.getClass() != Object[].class)
elementData = Arrays.copyOf(elementData, size, Object[].class);
} else {
// replace with empty array.
this.elementData = EMPTY_ELEMENTDATA;
}
    }
//当前容量值设置为实际个数
public void trimToSize() {
        modCount++;
        if (size < elementData.length) {
elementData = (size == 0)
                    ? EMPTY_ELEMENTDATA
: Arrays.copyOf(elementData, size);
}
    }
//判断容量，容量不够增加
public void ensureCapacity(int minCapacity) {
int minExpand = (elementData != DEFAULTCAPACITY_EMPTY_ELEMENTDATA)
// any size if not default element table
? 0
// larger than default for default empty table. It‘s already
                // supposed to be at default size.
: DEFAULT_CAPACITY;

        if (minCapacity > minExpand) {
            ensureExplicitCapacity(minCapacity);
}
    }
private void ensureCapacityInternal(int minCapacity) {
if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA) {
            minCapacity = Math.max(DEFAULT_CAPACITY, minCapacity);
}

        ensureExplicitCapacity(minCapacity);
}

private void ensureExplicitCapacity(int minCapacity) {
        modCount++;

// overflow-conscious code
if (minCapacity - elementData.length > 0)
            grow(minCapacity);
}
//最大的容量分配
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
    private void grow(int minCapacity) {
// overflow-conscious code
int oldCapacity = elementData.length;
        int newCapacity = oldCapacity + (oldCapacity >> 1);
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
// minCapacity is usually close to size, so this is a win:
elementData = Arrays.copyOf(elementData, newCapacity);
}

private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
        return (minCapacity > MAX_ARRAY_SIZE) ?
                Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
}
//返回ArrayList的大小
public int size() {
return size;
}
//判断ArrayList是否为空
public boolean isEmpty() {
return size == 0;
}
//判断是否含有某个对象
public boolean contains(Object o) {
return indexOf(o) >= 0;
}
//查找对象，返回坐标
public int indexOf(Object o) {
if (o == null) {
for (int i = 0; i < size; i++)
if (elementData[i]==null)
return i;
} else {
for (int i = 0; i < size; i++)
if (o.equals(elementData[i]))
return i;
}
return -1;
}
//返回对象相同的最后一个坐标
public int lastIndexOf(Object o) {
if (o == null) {
for (int i = size-1; i >= 0; i--)
if (elementData[i]==null)
return i;
} else {
for (int i = size-1; i >= 0; i--)
if (o.equals(elementData[i]))
return i;
}
return -1;
}
//返回一个影子对象克隆
public Object clone() {
try {
            ArrayList<?> v = (ArrayList<?>) super.clone();
v.elementData = Arrays.copyOf(elementData, size);
v.modCount = 0;
            return v;
} catch (CloneNotSupportedException e) {
// this shouldn‘t happen, since we are Cloneable
throw new InternalError(e);
}
    }
//返回一个包含所有ArrayList元素的数组
public Object[] toArray() {
return Arrays.copyOf(elementData, size);
}
//返回泛型对象数组，一般使用这个不是上边那个
@SuppressWarnings("unchecked")
public <T> T[] toArray(T[] a) {
if (a.length < size)
// Make a new array of a‘s runtime type, but my contents:
return (T[]) Arrays.copyOf(elementData, size, a.getClass());
System.arraycopy(elementData, 0, a, 0, size);
        if (a.length > size)
            a[size] = null;
        return a;
}
//得到指定下标的对象
@SuppressWarnings("unchecked")
E elementData(int index) {
return (E) elementData[index];
}
//得到指定下标的对象，并对下标进行判断
public E get(int index) {
        rangeCheck(index);

        return elementData(index);
}
//替换指定下标的对象，会检查下标并返回
public E set(int index, E element) {
        rangeCheck(index);

E oldValue = elementData(index);
elementData[index] = element;
        return oldValue;
}
//追加对象
public boolean add(E e) {
        ensureCapacityInternal(size + 1);  // Increments modCount!!
elementData[size++] = e;
        return true;
}
//在指定的下标后增加对象
public void add(int index, E element) {
        rangeCheckForAdd(index);

ensureCapacityInternal(size + 1);  // Increments modCount!!
System.arraycopy(elementData, index, elementData, index + 1,
size - index);
elementData[index] = element;
size++;
}
//删除指定坐标的对象
public E remove(int index) {
        rangeCheck(index);

modCount++;
E oldValue = elementData(index);

        int numMoved = size - index - 1;
        if (numMoved > 0)
            System.arraycopy(elementData, index+1, elementData, index,
numMoved);
elementData[--size] = null; // clear to let GC do its work

return oldValue;
}
// 删除ArrayList第一次出现的对象o
public boolean remove(Object o) {
if (o == null) {
for (int index = 0; index < size; index++)
if (elementData[index] == null) {
                    fastRemove(index);
                    return true;
}
        } else {
for (int index = 0; index < size; index++)
if (o.equals(elementData[index])) {
                    fastRemove(index);
                    return true;
}
        }
return false;
}
//删除
private void fastRemove(int index) {
        modCount++;
        int numMoved = size - index - 1;
        if (numMoved > 0)
            System.arraycopy(elementData, index+1, elementData, index,
numMoved);
elementData[--size] = null; // clear to let GC do its work
}
//清空ArrayList
public void clear() {
        modCount++;

// clear to let GC do its work
for (int i = 0; i < size; i++)
elementData[i] = null;

size = 0;
}
//将集合C追加到ArrayList中
public boolean addAll(Collection<? extends E> c) {
        Object[] a = c.toArray();
        int numNew = a.length;
ensureCapacityInternal(size + numNew);  // Increments modCount
System.arraycopy(a, 0, elementData, size, numNew);
size += numNew;
        return numNew != 0;
}
//在ArrayList中的某个坐标后追加集合c
public boolean addAll(int index, Collection<? extends E> c) {
        rangeCheckForAdd(index);

Object[] a = c.toArray();
        int numNew = a.length;
ensureCapacityInternal(size + numNew);  // Increments modCount
int numMoved = size - index;
        if (numMoved > 0)
            System.arraycopy(elementData, index, elementData, index + numNew,
numMoved);
System.arraycopy(a, 0, elementData, index, numNew);
size += numNew;
        return numNew != 0;
}
//删除范围中的对象
protected void removeRange(int fromIndex, int 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;
}
//范围检查
private void rangeCheck(int index) {
if (index >= size)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
//在添加或者添加所有的时候范围检查
private void rangeCheckForAdd(int index) {
if (index > size || index < 0)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+size;
}
public boolean removeAll(Collection<?> c) {
        Objects.requireNonNull(c);
        return batchRemove(c, false);
}
public boolean retainAll(Collection<?> c) {
        Objects.requireNonNull(c);
        return batchRemove(c, true);
}
//删除c中的在ArrayList中存在或者不存在的
private boolean batchRemove(Collection<?> c, boolean complement) {
final Object[] elementData = this.elementData;
        int r = 0, w = 0;
        boolean modified = false;
        try {
for (; r < size; r++)
if (c.contains(elementData[r]) == complement)
                    elementData[w++] = elementData[r];
} finally {
// Preserve behavioral compatibility with AbstractCollection,
            // even if c.contains() throws.
if (r != size) {
                System.arraycopy(elementData, r,
elementData, w,
size - r);
w += size - r;
}
if (w != size) {
// clear to let GC do its work
for (int i = w; i < size; i++)
                    elementData[i] = null;
modCount += size - w;
size = w;
modified = true;
}
        }
return modified;
}
//序列化
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException{
// Write out element count, and any hidden stuff
int expectedModCount = modCount;
s.defaultWriteObject();

// Write out size as capacity for behavioural compatibility with clone()
s.writeInt(size);

// Write out all elements in the proper order.
for (int i=0; i<size; i++) {
            s.writeObject(elementData[i]);
}

if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
    }
//反序列化
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
elementData = EMPTY_ELEMENTDATA;
// Read in size, and any hidden stuff
s.defaultReadObject();
// Read in capacity
s.readInt(); // ignored
if (size > 0) {
// be like clone(), allocate array based upon size not capacity
ensureCapacityInternal(size);
Object[] a = elementData;
// Read in all elements in the proper order.
for (int i=0; i<size; i++) {
                a[i] = s.readObject();
}
        }
    }

public ListIterator<E> listIterator(int index) {
if (index < 0 || index > size)
throw new IndexOutOfBoundsException("Index: "+index);
        return new ListItr(index);
}
public ListIterator<E> listIterator() {
return new ListItr(0);
}
public Iterator<E> iterator() {
return new Itr();
}
private class Itr implements Iterator<E> {
int cursor;       // index of next element to return
int lastRet = -1; // index of last element returned; -1 if no such
int expectedModCount = modCount;

        public boolean hasNext() {
return cursor != size;
}

@SuppressWarnings("unchecked")
public E next() {
            checkForComodification();
            int i = cursor;
            if (i >= size)
throw new NoSuchElementException();
Object[] elementData = ArrayList.this.elementData;
            if (i >= elementData.length)
throw new ConcurrentModificationException();
cursor = i + 1;
            return (E) elementData[lastRet = i];
}

public void remove() {
if (lastRet < 0)
throw new IllegalStateException();
checkForComodification();

            try {
                ArrayList.this.remove(lastRet);
cursor = lastRet;
lastRet = -1;
expectedModCount = modCount;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
        }

@Override
        @SuppressWarnings("unchecked")
public void forEachRemaining(Consumer<? super E> consumer) {
            Objects.requireNonNull(consumer);
            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++]);
}
// update once at end of iteration to reduce heap write traffic
cursor = i;
lastRet = i - 1;
checkForComodification();
}

final void checkForComodification() {
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
}
    }
private class ListItr extends Itr implements ListIterator<E> {
        ListItr(int index) {
super();
cursor = index;
}

public boolean hasPrevious() {
return cursor != 0;
}

public int nextIndex() {
return cursor;
}

public int previousIndex() {
return cursor - 1;
}

@SuppressWarnings("unchecked")
public E previous() {
            checkForComodification();
            int i = cursor - 1;
            if (i < 0)
throw new NoSuchElementException();
Object[] elementData = ArrayList.this.elementData;
            if (i >= elementData.length)
throw new ConcurrentModificationException();
cursor = i;
            return (E) elementData[lastRet = i];
}

public void set(E e) {
if (lastRet < 0)
throw new IllegalStateException();
checkForComodification();

            try {
                ArrayList.this.set(lastRet, e);
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
        }

public void add(E e) {
            checkForComodification();

            try {
int i = cursor;
ArrayList.this.add(i, e);
cursor = i + 1;
lastRet = -1;
expectedModCount = modCount;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
        }
    }
public List<E> subList(int fromIndex, int toIndex) {
subListRangeCheck(fromIndex, toIndex, size);
        return new SubList(this, 0, 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 + ")");
}

private class SubList extends AbstractList<E> implements RandomAccess {
private final AbstractList<E> parent;
        private final int parentOffset;
        private final int offset;
        int size;

SubList(AbstractList<E> parent,
                int offset, int fromIndex, int toIndex) {
this.parent = parent;
            this.parentOffset = fromIndex;
            this.offset = offset + fromIndex;
            this.size = toIndex - fromIndex;
            this.modCount = ArrayList.this.modCount;
}

public E set(int index, E e) {
            rangeCheck(index);
checkForComodification();
E oldValue = ArrayList.this.elementData(offset + index);
ArrayList.this.elementData[offset + index] = e;
            return oldValue;
}

public E get(int index) {
            rangeCheck(index);
checkForComodification();
            return ArrayList.this.elementData(offset + index);
}

public int size() {
            checkForComodification();
            return this.size;
}

public void add(int index, E e) {
            rangeCheckForAdd(index);
checkForComodification();
parent.add(parentOffset + index, e);
            this.modCount = parent.modCount;
            this.size++;
}

public E remove(int index) {
            rangeCheck(index);
checkForComodification();
E result = parent.remove(parentOffset + index);
            this.modCount = parent.modCount;
            this.size--;
            return result;
}

protected void removeRange(int fromIndex, int toIndex) {
            checkForComodification();
parent.removeRange(parentOffset + fromIndex,
parentOffset + toIndex);
            this.modCount = parent.modCount;
            this.size -= toIndex - fromIndex;
}

public boolean addAll(Collection<? extends E> c) {
return addAll(this.size, c);
}

public boolean addAll(int index, Collection<? extends E> c) {
            rangeCheckForAdd(index);
            int cSize = c.size();
            if (cSize==0)
return false;

checkForComodification();
parent.addAll(parentOffset + index, c);
            this.modCount = parent.modCount;
            this.size += cSize;
            return true;
}

public Iterator<E> iterator() {
return listIterator();
}

public ListIterator<E> listIterator(final int index) {
            checkForComodification();
rangeCheckForAdd(index);
            final int offset = this.offset;

            return new ListIterator<E>() {
int cursor = index;
                int lastRet = -1;
                int expectedModCount = ArrayList.this.modCount;

                public boolean hasNext() {
return cursor != SubList.this.size;
}

@SuppressWarnings("unchecked")
public E next() {
                    checkForComodification();
                    int i = cursor;
                    if (i >= SubList.this.size)
throw new NoSuchElementException();
Object[] elementData = ArrayList.this.elementData;
                    if (offset + i >= elementData.length)
throw new ConcurrentModificationException();
cursor = i + 1;
                    return (E) elementData[offset + (lastRet = i)];
}

public boolean hasPrevious() {
return cursor != 0;
}

@SuppressWarnings("unchecked")
public E previous() {
                    checkForComodification();
                    int i = cursor - 1;
                    if (i < 0)
throw new NoSuchElementException();
Object[] elementData = ArrayList.this.elementData;
                    if (offset + i >= elementData.length)
throw new ConcurrentModificationException();
cursor = i;
                    return (E) elementData[offset + (lastRet = i)];
}

@SuppressWarnings("unchecked")
public void forEachRemaining(Consumer<? super E> consumer) {
                    Objects.requireNonNull(consumer);
                    final int size = SubList.this.size;
                    int i = cursor;
                    if (i >= size) {
return;
}
final Object[] elementData = ArrayList.this.elementData;
                    if (offset + i >= elementData.length) {
throw new ConcurrentModificationException();
}
while (i != size && modCount == expectedModCount) {
                        consumer.accept((E) elementData[offset + (i++)]);
}
// update once at end of iteration to reduce heap write traffic
lastRet = cursor = i;
checkForComodification();
}

public int nextIndex() {
return cursor;
}

public int previousIndex() {
return cursor - 1;
}

public void remove() {
if (lastRet < 0)
throw new IllegalStateException();
checkForComodification();

                    try {
                        SubList.this.remove(lastRet);
cursor = lastRet;
lastRet = -1;
expectedModCount = ArrayList.this.modCount;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
                }

public void set(E e) {
if (lastRet < 0)
throw new IllegalStateException();
checkForComodification();

                    try {
                        ArrayList.this.set(offset + lastRet, e);
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
                }

public void add(E e) {
                    checkForComodification();

                    try {
int i = cursor;
SubList.this.add(i, e);
cursor = i + 1;
lastRet = -1;
expectedModCount = ArrayList.this.modCount;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
                }

final void checkForComodification() {
if (expectedModCount != ArrayList.this.modCount)
throw new ConcurrentModificationException();
}
            };
}

public List<E> subList(int fromIndex, int toIndex) {
subListRangeCheck(fromIndex, toIndex, size);
            return new SubList(this, offset, fromIndex, toIndex);
}

private void rangeCheck(int index) {
if (index < 0 || index >= this.size)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}

private void rangeCheckForAdd(int index) {
if (index < 0 || index > this.size)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}

private String outOfBoundsMsg(int index) {
return "Index: "+index+", Size: "+this.size;
}

private void checkForComodification() {
if (ArrayList.this.modCount != this.modCount)
throw new ConcurrentModificationException();
}

public Spliterator<E> spliterator() {
            checkForComodification();
            return new ArrayListSpliterator<E>(ArrayList.this, offset,
offset + this.size, this.modCount);
}
    }

@Override
public void forEach(Consumer<? super E> action) {
        Objects.requireNonNull(action);
        final int expectedModCount = modCount;
@SuppressWarnings("unchecked")
final E[] elementData = (E[]) this.elementData;
        final int size = this.size;
        for (int i=0; modCount == expectedModCount && i < size; i++) {
            action.accept(elementData[i]);
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
    }
@Override
public Spliterator<E> spliterator() {
return new ArrayListSpliterator<>(this, 0, -1, 0);
}

/** Index-based split-by-two, lazily initialized Spliterator */
static final class ArrayListSpliterator<E> implements Spliterator<E> {

private final ArrayList<E> 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<E> list, int origin, int fence,
                             int expectedModCount) {
this.list = list; // OK if null unless traversed
this.index = origin;
            this.fence = fence;
            this.expectedModCount = expectedModCount;
}

private int getFence() { // initialize fence to size on first use
int hi; // (a specialized variant appears in method forEach)
ArrayList<E> lst;
            if ((hi = fence) < 0) {
if ((lst = list) == null)
                    hi = fence = 0;
                else {
expectedModCount = lst.modCount;
hi = fence = lst.size;
}
            }
return hi;
}

public ArrayListSpliterator<E> trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
            return (lo >= mid) ? null : // divide range in half unless too small
new ArrayListSpliterator<E>(list, lo, index = mid,
expectedModCount);
}

public boolean tryAdvance(Consumer<? super E> action) {
if (action == null)
throw new NullPointerException();
            int hi = getFence(), i = index;
            if (i < hi) {
index = i + 1;
@SuppressWarnings("unchecked") E e = (E)list.elementData[i];
action.accept(e);
                if (list.modCount != expectedModCount)
throw new ConcurrentModificationException();
                return true;
}
return false;
}

public void forEachRemaining(Consumer<? super E> action) {
int i, hi, mc; // hoist accesses and checks from loop
ArrayList<E> lst; Object[] a;
            if (action == null)
throw new NullPointerException();
            if ((lst = list) != null && (a = lst.elementData) != null) {
if ((hi = fence) < 0) {
                    mc = lst.modCount;
hi = lst.size;
}
else
mc = expectedModCount;
                if ((i = index) >= 0 && (index = hi) <= a.length) {
for (; i < hi; ++i) {
@SuppressWarnings("unchecked") E e = (E) a[i];
action.accept(e);
}
if (lst.modCount == mc)
return;
}
            }
throw new ConcurrentModificationException();
}

public long estimateSize() {
return (long) (getFence() - index);
}

public int characteristics() {
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
}
    }

@Override
public boolean removeIf(Predicate<? super E> filter) {
        Objects.requireNonNull(filter);
// figure out which elements are to be removed
        // any exception thrown from the filter predicate at this stage
        // will leave the collection unmodified
int removeCount = 0;
        final BitSet removeSet = new BitSet(size);
        final int expectedModCount = modCount;
        final int size = this.size;
        for (int i=0; modCount == expectedModCount && i < size; i++) {
@SuppressWarnings("unchecked")
final E element = (E) elementData[i];
            if (filter.test(element)) {
                removeSet.set(i);
removeCount++;
}
        }
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
// shift surviving elements left over the spaces left by removed elements
final boolean anyToRemove = removeCount > 0;
        if (anyToRemove) {
final int newSize = size - removeCount;
            for (int i=0, j=0; (i < size) && (j < newSize); i++, j++) {
                i = removeSet.nextClearBit(i);
elementData[j] = elementData[i];
}
for (int k=newSize; k < size; k++) {
elementData[k] = null;  // Let gc do its work
}
this.size = newSize;
            if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
            modCount++;
}

return anyToRemove;
}

@Override
    @SuppressWarnings("unchecked")
public void replaceAll(UnaryOperator<E> operator) {
        Objects.requireNonNull(operator);
        final int expectedModCount = modCount;
        final int size = this.size;
        for (int i=0; modCount == expectedModCount && i < size; i++) {
elementData[i] = operator.apply((E) elementData[i]);
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
        modCount++;
}

@Override
    @SuppressWarnings("unchecked")
public void sort(Comparator<? super E> c) {
final int expectedModCount = modCount;
Arrays.sort((E[]) elementData, 0, size, c);
        if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
        modCount++;
}
}

Java-ArrayList源码分析及示例

标签：arraylist

原文地址：http://blog.csdn.net/qq924862077/article/details/48039521