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package ucar.nc2.ft.point;
import java.util.Iterator;
import java.util.NoSuchElementException;
import ucar.nc2.ft.PointFeature;
import ucar.nc2.ft.PointFeatureIterator;
/**
* Adapts an {@link Iterator}<{@link PointFeature}> to a {@link PointFeatureIterator}. The original iterator gains
* bounds calculation and compatibility with the rest of the Point Feature API.
*
* @author cwardgar
* @since 2014/08/30
*/
public class PointIteratorAdapter extends PointIteratorAbstract {
private final Iterator pointIter;
/**
* Creates a {@link PointFeatureIterator} from the supplied basic iterator.
*
* @param pointIter a basic iterator over point features.
*/
public PointIteratorAdapter(Iterator pointIter) {
this.pointIter = pointIter;
}
/**
* Returns {@code true} if the iteration has more elements. (In other words, returns {@code true} if {@link #next}
* would return an element rather than throwing an exception.)
*
* This method is idempotent, meaning that when it is called repeatedly without an intervening
* {@link #next}, calls after the first will have no effect.
*
* @return {@code true} if the iteration has more elements, {@code false} otherwise. A {@code false} return value
* {@link #close finishes} this iteration.
*/
// PointFeatureIterator.hasNext() doesn't guarantee idempotency, but we do.
@Override
public boolean hasNext() {
if (!pointIter.hasNext()) {
close();
return false;
} else {
return true;
}
}
/**
* Returns the next element in the iteration.
*
* @return the next element in the iteration
* @throws NoSuchElementException if the iteration has no more elements.
*/
// PointFeatureIterator.next() doesn't actually specify the behavior of next() when there are no more elements,
// but we can define a stronger contract.
@Override
public PointFeature next() throws NoSuchElementException {
if (!hasNext()) {
throw new NoSuchElementException("The iteration has no more elements.");
}
PointFeature pointFeat = pointIter.next();
assert pointFeat != null : "hasNext() should have been false. WTF?";
calcBounds(pointFeat);
return pointFeat;
}
/**
* Finishes bounds calculation, {@link #setCalculateBounds if it has been enabled}. Do not attempt to retrieve
* bounds information (via {@link #getBoundingBox}, {@link #getDateRange}, {@link #getCalendarDateRange}, or
* {@link #getCount}) before this method has been invoked or {@link #hasNext} returns {@code false}.
*
* This method is idempotent, meaning that calls after the first have no effect.
*/
@Override
public void close() {
finishCalcBounds(); // Method is idempotent.
}
}