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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package com.sun.xml.internal.ws.transport.http.server;

import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpServer;
import com.sun.xml.internal.ws.server.ServerRtException;

import java.net.InetSocketAddress;
import java.net.URL;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Logger;
import java.util.Optional;


/**
 * Manages all the WebService HTTP servers created by JAXWS runtime.
 *
 * @author Jitendra Kotamraju
 */
final class ServerMgr {

    private static final ServerMgr serverMgr = new ServerMgr();
    private static final Logger logger =
        Logger.getLogger(
            com.sun.xml.internal.ws.util.Constants.LoggingDomain + ".server.http");
    private final Map<InetSocketAddress,ServerState> servers = new HashMap<InetSocketAddress,ServerState>();

    private ServerMgr() {}

    /**
     * Gets the singleton instance.
     * @return manager instance
     */
    static ServerMgr getInstance() {
        return serverMgr;
    }

    /*
     * Creates a HttpContext at the given address. If there is already a server
     * it uses that server to create a context. Otherwise, it creates a new
     * HTTP server. This sever is added to servers Map.
     */
    /*package*/ HttpContext createContext(String address) {
        try {
            HttpServer server;
            ServerState state;
            URL url = new URL(address);
            int port = url.getPort();
            if (port == -1) {
                port = url.getDefaultPort();
            }
            InetSocketAddress inetAddress = new InetSocketAddress(url.getHost(),
                    port);
            synchronized(servers) {
                state = servers.get(inetAddress);
                if (state == null) {
                    final int finalPortNum = port;
                    Optional<ServerState> stateOpt =
                            servers.values()
                                    .stream()
                                    .filter(s -> s.getServer()
                                            .getAddress()
                                            .getPort() == finalPortNum)
                                    .findAny();

                    if (inetAddress.getAddress().isAnyLocalAddress() &&
                            stateOpt.isPresent()) {
                        state = stateOpt.get();
                    } else {
                        logger.fine("Creating new HTTP Server at "+inetAddress);
                        // Creates server with default socket backlog
                        server = HttpServer.create(inetAddress, 0);
                        server.setExecutor(Executors.newCachedThreadPool());
                        String path = url.toURI().getPath();
                        logger.fine("Creating HTTP Context at = "+path);
                        HttpContext context = server.createContext(path);
                        server.start();

                        // we have to get actual inetAddress from server, which can differ from the original in some cases.
                        // e.g. A port number of zero will let the system pick up an ephemeral port in a bind operation,
                        // or IP: 0.0.0.0 - which is used to monitor network traffic from any valid IP address
                        inetAddress = server.getAddress();

                        logger.fine("HTTP server started = "+inetAddress);
                        state = new ServerState(server, path);
                        servers.put(inetAddress, state);
                        return context;
                    }
                }
            }
            server = state.getServer();

            if (state.getPaths().contains(url.getPath())) {
                String err = "Context with URL path "+url.getPath()+ " already exists on the server "+server.getAddress();
                logger.fine(err);
                throw new IllegalArgumentException(err);
            }

            logger.fine("Creating HTTP Context at = "+url.getPath());
            HttpContext context = server.createContext(url.getPath());
            state.oneMoreContext(url.getPath());
            return context;
        } catch(Exception e) {
            throw new ServerRtException("server.rt.err",e );
        }
    }

    /*
     * Removes a context. If the server doesn't have anymore contexts, it
     * would stop the server and server is removed from servers Map.
     */
    /*package*/ void removeContext(HttpContext context) {
        InetSocketAddress inetAddress = context.getServer().getAddress();
        synchronized(servers) {
            ServerState state = servers.get(inetAddress);
            int instances = state.noOfContexts();
            if (instances < 2) {
                ((ExecutorService)state.getServer().getExecutor()).shutdown();
                state.getServer().stop(0);
                servers.remove(inetAddress);
            } else {
                state.getServer().removeContext(context);
                state.oneLessContext(context.getPath());
            }
        }
    }

    private static final class ServerState {
        private final HttpServer server;
        private int instances;
        private Set<String> paths = new HashSet<String>();

        ServerState(HttpServer server, String path) {
            this.server = server;
            this.instances = 1;
            paths.add(path);
        }

        public HttpServer getServer() {
            return server;
        }

        public void oneMoreContext(String path) {
            ++instances;
            paths.add(path);
        }

        public void oneLessContext(String path) {
            --instances;
            paths.remove(path);
        }

        public int noOfContexts() {
            return instances;
        }

        public Set<String> getPaths() {
            return paths;
        }
    }
}