001package ca.uhn.fhir.util;
002
003/*
004 * #%L
005 * HAPI FHIR - Core Library
006 * %%
007 * Copyright (C) 2014 - 2017 University Health Network
008 * %%
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 * 
013 *      http://www.apache.org/licenses/LICENSE-2.0
014 * 
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 * #L%
021 */
022
023import java.net.ServerSocket;
024
025/**
026 * Provides server ports
027 */
028@CoverageIgnore
029public class PortUtil {
030
031        /*
032         * Non instantiable
033         */
034        private PortUtil() {
035                // nothing
036        } 
037        
038        /**
039         * This is really only used for unit tests but is included in the library so it can be reused across modules. Use with caution.
040         */
041        public static int findFreePort() {
042                ServerSocket server;
043                try {
044                        server = new ServerSocket(0);
045                        int port = server.getLocalPort();
046                        server.close();
047                        Thread.sleep(500);
048                        return port;
049                } catch (Exception e) {
050                        //FIXME resource leak
051                        throw new Error(e);
052                }
053        }
054
055}
056