    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
    017    package com.google.common.collect;
    018
    019    import com.google.common.annotations.GwtCompatible;
    020
    021    import java.util.Iterator;
    022
    023    /**
    024     * An iterator that does not support {@link #remove}.
    025     *
    026     * @author Jared Levy
    027     * @since 2.0 (imported from Google Collections Library)
    028     */
    029    @GwtCompatible
    030    public abstract class UnmodifiableIterator<E> implements Iterator<E> {
    031      /** Constructor for use by subclasses. */
    032      protected UnmodifiableIterator() {}
    033
    034      /**
    035       * Guaranteed to throw an exception and leave the underlying data unmodified.
    036       *
    037       * @throws UnsupportedOperationException always
    038       */
    039      @Override
    040      public final void remove() {
    041        throw new UnsupportedOperationException();
    042      }
    043    }