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ConcurrentUnsafeIterableArrayList.java
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ConcurrentUnsafeIterableArrayList.java
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package me.nallar.collections;
import java.util.ArrayList;
import me.nallar.tickthreading.util.ReflectUtil;
import me.nallar.unsafe.UnsafeAccess;
import sun.misc.Unsafe;
public class ConcurrentUnsafeIterableArrayList<T> extends ArrayList<T> {
private static final Unsafe $ = UnsafeAccess.$;
private static final long elementDataIndex = getIndex();
private static long getIndex() {
return $.objectFieldOffset(ReflectUtil.getField(ArrayList.class, "elementData"));
}
public Object[] elementData() {
return (Object[]) $.getObject(this, elementDataIndex);
}
public java.util.Iterator<T> unsafeIterator() {
return new Iterator(elementData(), size());
}
private static class Iterator<T> implements java.util.Iterator<T> {
final Object[] elementData;
int index;
private Object next;
private Object getNext() {
Object l = next;
Object o;
int i = index;
if (i == -1) {
next = null;
} else {
do {
o = elementData[i];
} while (--i != -1 && (o == null || o == l));
index = i;
next = o;
}
return l;
}
Iterator(final Object[] elementData, int start) {
this.elementData = elementData;
if (start >= elementData.length) {
start = elementData.length - 1;
}
index = start;
getNext();
}
@Override
public boolean hasNext() {
return next != null;
}
@Override
public T next() {
Object o = getNext();
if (o == null) {
throw new IllegalStateException("Must call hasNext before next");
}
return (T) o;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}