de.th.wildau.dsc.sne.webserver.WebServer.java Source code

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Here is the source code for de.th.wildau.dsc.sne.webserver.WebServer.java

Source

package de.th.wildau.dsc.sne.webserver;

import java.io.File;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.cli.PosixParser;

/**
 * This is the main web server class. License creative commons (cc) by-nc-sa.
 */
public class WebServer {

    protected static List<ScriptLanguage> supportedScriptLanguages;

    /**
     * The main method for the web server program.
     * 
     * @param args
     */
    public static void main(String[] startArguments) {

        new WebServer(startArguments);
    }

    /**
     * Web server / main constructor.
     * 
     * @param startArguments
     */
    public WebServer(String[] startArguments) {

        loadConfiguration(startArguments);
        Log.debug(Configuration.getInstance().toString());

        Log.debug("Information about the OS: " + System.getProperty("os.name") + " - "
                + System.getProperty("os.version") + " - " + System.getProperty("os.arch"));

        if (Configuration.getConfig().getProxyHost() != null) {
            Log.debug("setup proxy configuration");
            System.setProperty("http.proxyHost", Configuration.getConfig().getProxyHost());
            System.setProperty("http.proxyPort", String.valueOf(Configuration.getConfig().getProxyPort()));
        }

        Log.debug("find supported scripting languages");
        supportedScriptLanguages = Collections.unmodifiableList(ScriptExecutor.getSupportedScriptLanguages());
        Log.debug("Supported Script Languages " + Arrays.toString(supportedScriptLanguages.toArray()));

        Log.info("instantiating web server");
        try {
            ServerSocket server = new ServerSocket(Configuration.getConfig().getServerPort());
            Log.debug("bound port " + Configuration.getConfig().getServerPort());

            int corePoolSize = Runtime.getRuntime().availableProcessors();
            int maxPoolSize = (2 * corePoolSize) + 1;
            Log.debug("core/max pool size: " + corePoolSize + "/" + maxPoolSize);
            LinkedBlockingQueue<Runnable> workerQueue = new LinkedBlockingQueue<Runnable>();
            long keepAliveTime = 30;
            /*
             * keepAliveTime - If the pool currently has more than corePoolSize
             * threads, excess threads will be terminated if they have been idle
             * for more than the keepAliveTime.
             */

            ThreadPoolExecutor threadPool = new ThreadPoolExecutor(corePoolSize, maxPoolSize, keepAliveTime,
                    TimeUnit.SECONDS, workerQueue);
            threadPool.prestartAllCoreThreads();

            Socket socket = null;
            while (true) {

                try {
                    socket = server.accept();
                    Log.info(socket.getInetAddress().getHostName() + " client request");
                    threadPool.execute(new HttpHandler(socket));
                    Log.debug("current threads: " + threadPool.getActiveCount());
                } catch (final IOException ex) {
                    Log.error("Connection failed!", ex);
                } catch (final RejectedExecutionException ex) {
                    // XXX [sne] RejectedExecutionException
                    // http://stackoverflow.com/questions/1519725/why-does-executors-newcachedthreadpool-throw-java-util-concurrent-rejectedexecut
                    // http://www.javamex.com/tutorials/threads/thread_pools_queues.shtml
                    // http://stackoverflow.com/questions/2001086/how-to-make-threadpoolexecutors-submit-method-block-if-it-is-saturated
                    Log.error("RejectedExecutionException", ex);
                    socket.close();
                } catch (final Exception ex) {
                    Log.fatal("Unknown error!", ex);
                }
            }
        } catch (final IOException ex) {
            Log.fatal("Can not start the server!", ex);
            System.err.println("Can not start the server! " + ex.getMessage());
        } catch (final Exception ex) {
            Log.fatal("Unknown error!", ex);
        }
    }

    /**
     * Load the web server configuration. <b>DON'T USE LOG BEFORE THIS METHOD
     * CALL!</b>
     * 
     * @param startArguments
     *            array
     */
    private void loadConfiguration(String[] startArguments) {

        Options options = new Options();
        options.addOption("c", true, "specify server configuration file");
        HelpFormatter helpFormatter = new HelpFormatter();
        helpFormatter.printHelp("WebServer", options);
        CommandLineParser parser = new PosixParser();
        CommandLine cmd;
        try {
            cmd = parser.parse(options, startArguments);
        } catch (final ParseException ex) {
            throw new IllegalStateException("Can not parse start arguments. " + ex.getMessage());
        }

        try {
            if (cmd.hasOption("c")) {
                File configFile = new File(cmd.getOptionValue("c"));
                if (configFile.isFile() && configFile.canRead()) {
                    Configuration.createInstance(configFile);
                }
            } else {
                // load default configuration
                Configuration.createInstance();
                System.out.println("Load default config: " + Configuration.getConfig().toString());
            }

            Log.createInstance();
            Log.info("loaded server configuration");
        } catch (final Exception ex) {
            System.err.println("Can not load server configuration file.");
        }
    }
}