Java tutorial
//package com.java2s; /* * JBoss, Home of Professional Open Source * Copyright 2005, JBoss Inc., and individual contributors as indicated * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import java.util.HashSet; import java.util.Set; public class Main { /** Indicates whether collection elements should be actually checked. */ private static final boolean DEBUG = false; /** * Ensures that all elements of the given set can be cast to a desired type. * * @param list the set to check * @param type the desired type * @return a set of the desired type * @throws ClassCastException if an element cannot be cast to the desired type */ @SuppressWarnings("unchecked") public static <E> Set<E> checkSet(Set<?> set, Class<E> type) { if (DEBUG) { Set<E> copy = new HashSet<E>(); for (Object element : set) { copy.add(type.cast(element)); } return copy; } return (Set<E>) set; } }