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Apache Commons Compress defines an API for working with compression and archive formats. These include bzip2, gzip, pack200, LZMA, XZ, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.

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/*
 * 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.commons.compress.utils;

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

/**
 * Iterator utilities.
 *
 * @since 1.13.
 */
public class Iterators {

    /**
     * Adds all the elements in the source {@code iterator} to the target
     * {@code collection}.
     *
     * 
     * When this method returns, the {@code iterator} will be "empty": its
     * {@code hasNext()} method returns {@code false}.
     * 
     *
     * @param  type of the elements contained inside the collection
     * @param collection target collection
     * @param iterator source
     * @return {@code true} if the target {@code collection} was modified as a
     *         result of this operation
     */
    public static  boolean addAll(final Collection collection, final Iterator iterator) {
        Objects.requireNonNull(collection);
        Objects.requireNonNull(iterator);
        boolean wasModified = false;
        while (iterator.hasNext()) {
            wasModified |= collection.add(iterator.next());
        }
        return wasModified;
    }

    private Iterators() {
        // do not instantiate
    }

}