Java tutorial
//package com.java2s; /* * 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. */ import java.util.HashSet; public class Main { /** * Extract a set of Integer indices into an int[]. * @param coll {@code HashSet} of {@code Integer} * @return int[] * @since 3.0.1 */ private static int[] extractIndices(HashSet<Integer> coll) { int[] result = new int[coll.size()]; int i = 0; for (Integer index : coll) { result[i++] = index.intValue(); } return result; } }