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Provides common utility functions

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/*
 * Copyright (c) CQSE GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.conqat.lib.commons.collections;

import java.util.Iterator;

/**
 * This is a wrapper for a {@link Iterator} prohibiting all calls which would modify its owning
 * container. All prohibited methods throw an {@link UnsupportedOperationException}.
 * 
 * @author Benjamin Hummel
 */
public class UnmodifiableIterator implements Iterator {

	/** The underlying iterator. */
	private final Iterator i;

	/**
	 * Creates a new unmodifiable iterator from another iterator. All modifications to the underlying
	 * iterator will directly be visible in this wrapper.
	 */
	public UnmodifiableIterator(Iterator i) {
		if (i == null) {
			throw new IllegalArgumentException("Underlying iterator may not be null!");
		}
		this.i = i;
	}

	/** {@inheritDoc} */
	@Override
	public boolean hasNext() {
		return i.hasNext();
	}

	/** {@inheritDoc} */
	@Override
	public E next() {
		return i.next();
	}

	/** Operation is not supported. */
	@Override
	public void remove() {
		throw new UnsupportedOperationException();
	}
}