Java 7 new features - 9. Fork/Join : CDR Loading example

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In the telecommunication environment, CDR(Call Detail Record) files are widely used. It is very important to load CDR files efficiently. Fortunately, the fork/join framework helps developers take advantage of multiple processors which are used in almost every server.

 
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;

public class CDRLoadingForkJoin
    extends RecursiveAction
{
    static final int FILE_COUNT_THRESHOLD = 1;
    File[] cdrFiles = null;

    public CDRLoadingForkJoin(File[] cdrFiles)
    {
        this.cdrFiles = cdrFiles;
    }

    @Override
    protected void compute()
    {
        try
        {
            // Check the number of files
            if (cdrFiles.length <= FILE_COUNT_THRESHOLD)
            {
                loadCDRFiles(cdrFiles);
            }
            else
            {
                // Split the array of CDR files into two equal parts
                int center = cdrFiles.length / 2;
                File[] part1 = splitArray(cdrFiles, 0, center);
                File[] part2 = splitArray(cdrFiles, center, cdrFiles.length);
                invokeAll(new CDRLoadingForkJoin(part1), new CDRLoadingForkJoin(part2));
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    protected File[] splitArray(File[] array, int start, int end)
    {
        int length = end - start;
        File[] part = new File[length];
        for (int i = start; i < end; i++)
        {
            part[i - start] = array[i];
        }
        return part;
    }

    protected void loadCDRFiles(File[] filesToLoad)
    {
        for (File file: filesToLoad)
        {
            if (file.getName().endsWith(".cdr"))
            {
                try
                {
                    BufferedReader reader = new BufferedReader(new FileReader(file));
                    String line = null;
                    while ((line = reader.readLine()) != null)
                    {
                        //load to database ..
                    }
                }
                catch (Exception e)
                {
                    e.printStackTrace();
                }
            }
        }
    }

    // Start the CDR file loading process with the Java SE 7 Fork/Join framework
    public static void main(String[] args)
    {
        String cdrDirPath = "D:\\CDR\\";
        File cdrDir = new File(cdrDirPath);
        if(!cdrDir.isDirectory())
        {
            System.err.println(cdrDirPath + " is not a valid directory");
        }
        File[] files = cdrDir.listFiles();
        CDRLoadingForkJoin process = new CDRLoadingForkJoin(files);
        int processors = Runtime.getRuntime().availableProcessors();
        ForkJoinPool pool = new ForkJoinPool(processors);
        pool.invoke(process);
    }
}

Java 7 new features - 8. NIO2 : F. Review - Traditional TCP server/client example

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After we learnt how the NIO2 works, let's review the traditional socket programming
Traditional TCP Server

 
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class TraditionalTcpSocketServer
{
    public static void main(String[] argv)
        throws Exception
    {
        String clientSentence;
        ServerSocket welcomeSocket = new ServerSocket(9001);
        while (true)
        {
            Socket connectionSocket = welcomeSocket.accept();
            BufferedReader inFromClient = new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
            DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
            clientSentence = inFromClient.readLine();
            System.out.println("FROM CLIENT: " + clientSentence);
            outToClient.writeBytes("World" + System.getProperty("line.separator"));
        }
    }
}

Traditional TCP Client

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.Socket;

public class TraditionalTcpSocketClient
{
    public static void main(String[] argv)
        throws Exception
    {
        String sentence = "Hello";
        String modifiedSentence;
        Socket clientSocket = new Socket("localhost", 9001);
        DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
        BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        outToServer.writeBytes(sentence + System.getProperty("line.separator"));
        modifiedSentence = inFromServer.readLine();
        System.out.println("FROM SERVER: " + modifiedSentence);
        clientSocket.close();
    }
}