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package org.eclipse.net4j.util.collection;
import java.util.ArrayList;
/**
* A list with O(1) effort for random access.
*
* @author Eike Stepper
*/
public final class MoveableArrayList<E> extends ArrayList<E> implements MoveableList<E>
{
private static final long serialVersionUID = 1L;
public MoveableArrayList(int initialCapacity)
{
super(initialCapacity);
}
public E move(int targetIndex, int sourceIndex)
{
int size = size();
if (sourceIndex >= size)
{
throw new IndexOutOfBoundsException("sourceIndex=" + sourceIndex + ", size=" + size);
}
if (targetIndex >= size)
{
throw new IndexOutOfBoundsException("targetIndex=" + targetIndex + ", size=" + size);
}
E object = get(sourceIndex);
if (targetIndex == sourceIndex)
{
return object;
}
if (targetIndex < sourceIndex)
{
moveUp1(targetIndex, sourceIndex - targetIndex);
}
else
{
moveDown1(targetIndex, targetIndex - sourceIndex);
}
set(targetIndex, object);
return object;
}
private void moveUp1(int index, int count)
{
for (int i = count; i > 0; i--)
{
set(index + i, get(index + i - 1));
}
}
private void moveDown1(int index, int count)
{
for (int i = count; i > 0; i--)
{
set(index - i, get(index - i + 1));
}
}
}
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