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/*
 * Copyright (c) 2010 Mysema Ltd.
 * All rights reserved.
 *
 */
package com.mysema.query.jpa.hibernate;

import java.util.NoSuchElementException;

import javax.annotation.Nullable;

import org.hibernate.ScrollableResults;

import com.mysema.commons.lang.CloseableIterator;

/**
 * ScrollableResultsIterator is an CloseableIterator adapter for ScrollableResults
 *
 * @author tiwe
 *
 * @param 
 */
public class ScrollableResultsIterator implements CloseableIterator {

    private final ScrollableResults results;

    private final boolean asArray;

    @Nullable
    private Boolean hasNext;

    public ScrollableResultsIterator(ScrollableResults results) {
        this(results, false);
    }

    public ScrollableResultsIterator(ScrollableResults results, boolean asArray) {
        this.results = results;
        this.asArray = asArray;
    }

    @Override
    public void close(){
        results.close();
    }

    @Override
    public boolean hasNext() {
        if (hasNext == null){
            hasNext = results.next();
        }
        return hasNext;
    }

    @Override
    @SuppressWarnings("unchecked")
    public T next() {
        if (hasNext()){
            hasNext = null;
            if (asArray) {
                return (T) results.get();
            } else {
                return (T) results.get(0);
            }
        }else{
            throw new NoSuchElementException();
        }
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException();
    }

}