rangeiteratordecorator.java

jsr170接口的java实现。是个apache的开源项目。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.jackrabbit.commons.iterator;

import java.util.NoSuchElementException;

import javax.jcr.RangeIterator;

/**
 * Base class for decorating {@link RangeIterator}s.
 */
public class RangeIteratorDecorator implements RangeIterator {

	/**
	 * The decorated iterator.
	 */
	private final RangeIterator iterator;

	/**
	 * Creates a decorated iterator. Protected since this class is only
	 * useful when subclassed.
	 *
	 * @param iterator the iterator to be decorated
	 */
	protected RangeIteratorDecorator(RangeIterator iterator) {
		this.iterator = iterator;
	}

	//-------------------------------------------------------< RangeIterator >

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @return iterator position
	 */
	public long getPosition() {
		return iterator.getPosition();
	}

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @return iterator size
	 */
	public long getSize() {
		return iterator.getSize();
	}

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @param n number of elements to skip
	 * @throws NoSuchElementException if skipped past the last element
	 */
	public void skip(long n) throws NoSuchElementException {
		iterator.skip(n);
	}

	//------------------------------------------------------------< Iterator >

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @return <code>true</code> if the iterator has more elements,
	 *         <code>false</code> otherwise
	 */
	public boolean hasNext() {
		return iterator.hasNext();
	}

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @return next element
	 * @throws NoSuchElementException if there are no more elements
	 */
	public Object next() throws NoSuchElementException {
		return iterator.next();
	}

	/**
	 * Delegated to the underlying iterator.
	 *
	 * @throws UnsupportedOperationException if the operation is not supported
	 * @throws IllegalStateException if there is no element to be removed
	 */
	public void remove()
			throws UnsupportedOperationException, IllegalStateException {
		iterator.remove();
	}
}