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/*
 * #%L
 * The AIBench Shell Plugin
 * %%
 * Copyright (C) 2006 - 2017 Daniel Glez-Peña and Florentino Fdez-Riverola
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */
package bsh.collection;

import java.util.Collection;
import java.util.Iterator;

/**
 * This is the implementation of: BshIterator - a dynamically loaded extension
 * that supports the collections API supported by JDK1.2 and greater.
 * 
 * @author Daniel Leuck
 * @author Pat Niemeyer
 */
public class CollectionIterator implements bsh.BshIterator {
	private Iterator iterator;

	/**
	 * Construct a basic CollectionIterator
	 * 
	 * @param iterateOverMe
	 *            the object over which we are iterating
	 * 
	 * @throws java.lang.IllegalArgumentException
	 *             If the argument is not a supported (i.e. iterable) type.
	 * 
	 * @throws java.lang.NullPointerException
	 *             If the argument is null
	 */
	public CollectionIterator(Object iterateOverMe) throws NullPointerException, IllegalArgumentException {
		iterator = createIterator(iterateOverMe);
	}

	/**
	 * Create an iterator over the given object
	 * 
	 * @param iterateOverMe
	 *            Object of type Iterator, Collection, or types supported by
	 *            CollectionManager.BasicBshIterator
	 * 
	 * @return an Iterator
	 * 
	 * @throws java.lang.IllegalArgumentException
	 *             If the argument is not a supported (i.e. iterable) type.
	 * 
	 * @throws java.lang.NullPointerException
	 *             If the argument is null
	 */
	protected Iterator createIterator(Object iterateOverMe) throws NullPointerException, IllegalArgumentException {
		if (iterateOverMe == null)
			throw new NullPointerException("Object arguments passed to " + "the CollectionIterator constructor cannot be null.");

		if (iterateOverMe instanceof Iterator)
			return (Iterator) iterateOverMe;

		if (iterateOverMe instanceof Collection)
			return ((Collection) iterateOverMe).iterator();

		/*
		 * Should we be able to iterate over maps? if (iterateOverMe instanceof
		 * Map) return ((Map)iterateOverMe).entrySet().iterator();
		 */

		throw new IllegalArgumentException("Cannot enumerate object of type " + iterateOverMe.getClass());
	}

	/**
	 * Fetch the next object in the iteration.
	 * 
	 * @return the next object.
	 */
	public Object next() {
		return iterator.next();
	}

	/**
	 * Returns {@code true} if and only if there are more objects available via
	 * the {@code next()} method.
	 * 
	 * @return the next object.
	 */
	public boolean hasNext() {
		return iterator.hasNext();
	}
}