001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect;
018
019import com.google.common.annotations.GwtCompatible;
020
021import java.util.Iterator;
022
023/**
024 * An iterator that does not support {@link #remove}.
025 *
026 * <p>{@code UnmodifiableIterator} is used primarily in conjunction with implementations of
027 * {@link ImmutableCollection}, such as {@link ImmutableList}. You can, however, convert an existing
028 * iterator to an {@code UnmodifiableIterator} using {@link Iterators#unmodifiableIterator}.
029 *
030 * @author Jared Levy
031 * @since 2.0
032 */
033@GwtCompatible
034public abstract class UnmodifiableIterator<E> implements Iterator<E> {
035  /** Constructor for use by subclasses. */
036  protected UnmodifiableIterator() {}
037
038  /**
039   * Guaranteed to throw an exception and leave the underlying data unmodified.
040   *
041   * @throws UnsupportedOperationException always
042   * @deprecated Unsupported operation.
043   */
044  @Deprecated
045  @Override
046  public final void remove() {
047    throw new UnsupportedOperationException();
048  }
049}