package com.bigdata.service.ndx;
import com.bigdata.btree.proc.IResultHandler;
import com.bigdata.service.Split;
/**
* Hands back the object visited for a single index partition.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public class IdentityHandler<T> implements IResultHandler<T, T> {
private int nvisited = 0;
private T ret;
@Override
public void aggregate(final T result, final Split split) {
synchronized (this) {
if (nvisited != 0) {
/*
* You can not use this handler if the procedure is mapped over
* more than one split.
*/
throw new UnsupportedOperationException();
}
this.ret = result;
nvisited++;
}
}
@Override
public T getResult() {
synchronized (this) {
return ret;
}
}
}