source: src/main/java/geniusweb/partiesserver/Constants.java

package geniusweb.partiesserver;

import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Set;

import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.Query;

import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * A central class containing the constants/configuration of the server.
 * 
 * <b> This class should is private to the server and should not be used by
 * others. However servers that derive from this server can completely override
 * this class to change the constants/configuration</b>
 */
public class Constants {
        private static transient ObjectMapper jackson; // cache
        private static transient String hostport = ""; // cache

        /**
         * 
         * @return the object mapper, so that we can extend the objectmapper (with
         *         custom classes) centrally. Also allows us to cache the objectmapper
         */
        public static ObjectMapper getJackson() {
                if (jackson == null) {
                        jackson = new ObjectMapper();
                }
                return jackson;
        }

        /**
         * 
         * @return a string like "127.0.1.1:8080" containing the server address on which
         *         this service is running.
         * @throws UnknownHostException         if we can not get the host ip
         * @throws MalformedObjectNameException if we can not get the host ip
         */
        public static String getIpAddressAndPort() throws UnknownHostException, MalformedObjectNameException {
                synchronized (hostport) {
                        if (hostport.isEmpty()) {
                                MBeanServer beanServer = ManagementFactory.getPlatformMBeanServer();

                                Set<ObjectName> objectNames = beanServer.queryNames(new ObjectName("*:type=Connector,*"),
                                                Query.match(Query.attr("protocol"), Query.value("HTTP/1.1")));

                                String host = InetAddress.getLocalHost().getHostAddress();
                                String port = objectNames.iterator().next().getKeyProperty("port");

                                hostport = host + ":" + port;
                        }
                        return hostport;
                }

        }
}