Example usage for java.nio ByteBuffer clear

List of usage examples for java.nio ByteBuffer clear

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Introduction

In this page you can find the example usage for java.nio ByteBuffer clear.

Prototype

public final Buffer clear()

Source Link

Document

Clears this buffer.

Usage

From source file:Main.java

public static void main(String[] args) throws Exception {
    DatagramChannel server = null;
    server = DatagramChannel.open();
    InetSocketAddress sAddr = new InetSocketAddress("localhost", 8989);
    server.bind(sAddr);//from w w  w  . j  ava2s. co  m
    ByteBuffer buffer = ByteBuffer.allocate(1024);

    while (true) {
        System.out.println("Waiting for a  message  from" + "  a  remote  host at " + sAddr);
        SocketAddress remoteAddr = server.receive(buffer);
        buffer.flip();
        int limits = buffer.limit();
        byte bytes[] = new byte[limits];
        buffer.get(bytes, 0, limits);
        String msg = new String(bytes);

        System.out.println("Client at " + remoteAddr + "  says: " + msg);
        buffer.rewind();
        server.send(buffer, remoteAddr);
        buffer.clear();
    }
    //server.close();
}

From source file:MainClass.java

public static void main(String[] args) {
    long[] primes = new long[] { 1, 2, 3, 5, 7 };
    File aFile = new File("C:/test/primes.bin");
    FileOutputStream outputFile = null;
    try {//  w w w. ja  va 2s  . c om
        outputFile = new FileOutputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel file = outputFile.getChannel();
    final int BUFFERSIZE = 100;
    ByteBuffer buf = ByteBuffer.allocate(BUFFERSIZE);
    LongBuffer longBuf = buf.asLongBuffer();
    int primesWritten = 0;
    while (primesWritten < primes.length) {
        longBuf.put(primes, primesWritten, min(longBuf.capacity(), primes.length - primesWritten));
        buf.limit(8 * longBuf.position());
        try {
            file.write(buf);
            primesWritten += longBuf.position();
        } catch (IOException e) {
            e.printStackTrace(System.err);
        }
        longBuf.clear();
        buf.clear();
    }
    try {
        System.out.println("File written is " + file.size() + "bytes.");
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

public static void main(String[] args) throws Exception {
    createFile();// w ww. ja  v a  2s .c  o  m

    File aFile = new File("C:/primes.bin");
    FileInputStream inFile = new FileInputStream(aFile);

    FileChannel inChannel = inFile.getChannel();

    final int PRIMESREQUIRED = 10;
    ByteBuffer buf = ByteBuffer.allocate(8 * PRIMESREQUIRED);

    long[] primes = new long[PRIMESREQUIRED];
    int index = 0; // Position for a prime in the file

    // Count of primes in the file
    final int PRIMECOUNT = (int) inChannel.size() / 8;

    // Read the number of random primes required
    for (int i = 0; i < PRIMESREQUIRED; i++) {
        index = 8 * (int) (PRIMECOUNT * Math.random());
        inChannel.read(buf, index); // Read the value
        buf.flip();
        primes[i] = buf.getLong(); // Save it in the array
        buf.clear();
    }

    for (long prime : primes) {
        System.out.printf("%12d", prime);
    }
    inFile.close(); // Close the file and the channel

}

From source file:MainClass.java

public static void main(String[] args) {
    int count = 100;

    long[] numbers = new long[count];

    for (int i = 0; i < numbers.length; i++) {
        numbers[i] = i;/* ww  w .j av  a2s. c  o  m*/

    }
    File aFile = new File("data.bin");
    FileOutputStream outputFile = null;
    try {
        outputFile = new FileOutputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
    FileChannel file = outputFile.getChannel();
    final int BUFFERSIZE = 100;
    ByteBuffer buf = ByteBuffer.allocate(BUFFERSIZE);
    LongBuffer longBuf = buf.asLongBuffer();

    int numberWritten = 0;

    while (numberWritten < numbers.length) {
        longBuf.put(numbers, numberWritten, min(longBuf.capacity(), numbers.length - numberWritten));
        buf.limit(8 * longBuf.position());
        try {
            file.write(buf);
            numberWritten += longBuf.position();
        } catch (IOException e) {
            e.printStackTrace(System.err);
            System.exit(1);
        }
        longBuf.clear();
        buf.clear();
    }

    try {
        System.out.println("File written is " + file.size() + " bytes.");
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

From source file:Main.java

public static void main(String[] args) throws Exception {
    File aFile = new File("main.java");
    FileInputStream inFile = new FileInputStream(aFile);
    FileChannel inChannel = inFile.getChannel();
    ByteBuffer lengthBuf = ByteBuffer.allocate(8);
    while (true) {
        if (inChannel.read(lengthBuf) == -1) {
            break;
        }/*w ww  .ja v  a  2s .  c  o m*/
        lengthBuf.flip();
        int strLength = (int) lengthBuf.getDouble();
        ByteBuffer buf = ByteBuffer.allocate(2 * strLength + 8);
        if (inChannel.read(buf) == -1) {
            break;
        }
        buf.flip();
        byte[] strChars = new byte[2 * strLength];
        buf.get(strChars);
        System.out.println(strLength);
        System.out.println(ByteBuffer.wrap(strChars).asCharBuffer());
        System.out.println(buf.getLong());
        lengthBuf.clear();
    }
    inFile.close();
}

From source file:GetWebPageDemo.java

public static void main(String args[]) throws Exception {
    String resource, host, file;/* ww w  . ja v  a 2 s  . c o m*/
    int slashPos;

    resource = "www.java2s.com/index.htm";
    slashPos = resource.indexOf('/'); // find host/file separator
    if (slashPos < 0) {
        resource = resource + "/";
        slashPos = resource.indexOf('/');
    }
    file = resource.substring(slashPos); // isolate host and file parts
    host = resource.substring(0, slashPos);
    System.out.println("Host to contact: '" + host + "'");
    System.out.println("File to fetch : '" + file + "'");

    SocketChannel channel = null;

    try {
        Charset charset = Charset.forName("ISO-8859-1");
        CharsetDecoder decoder = charset.newDecoder();
        CharsetEncoder encoder = charset.newEncoder();

        ByteBuffer buffer = ByteBuffer.allocateDirect(1024);
        CharBuffer charBuffer = CharBuffer.allocate(1024);

        InetSocketAddress socketAddress = new InetSocketAddress(host, 80);
        channel = SocketChannel.open();
        channel.connect(socketAddress);

        String request = "GET " + file + " \r\n\r\n";
        channel.write(encoder.encode(CharBuffer.wrap(request)));

        while ((channel.read(buffer)) != -1) {
            buffer.flip();
            decoder.decode(buffer, charBuffer, false);
            charBuffer.flip();
            System.out.println(charBuffer);
            buffer.clear();
            charBuffer.clear();
        }
    } catch (UnknownHostException e) {
        System.err.println(e);
    } catch (IOException e) {
        System.err.println(e);
    } finally {
        if (channel != null) {
            try {
                channel.close();
            } catch (IOException ignored) {
            }
        }
    }

    System.out.println("\nDone.");
}

From source file:MainClass.java

public static void main(String[] args) {
    File aFile = new File("data.dat");
    FileInputStream inFile = null;

    try {/*from w  ww  .ja v  a2s .  c o m*/
        inFile = new FileInputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }

    FileChannel inChannel = inFile.getChannel();
    final int COUNT = 6;
    ByteBuffer buf = ByteBuffer.allocate(8 * COUNT);
    long[] data = new long[COUNT];
    try {
        int pos = 0;
        while (inChannel.read(buf) != -1) {
            try {
                ((ByteBuffer) (buf.flip())).asLongBuffer().get(data);
                pos = data.length;
            } catch (BufferUnderflowException e) {
                LongBuffer longBuf = buf.asLongBuffer();
                pos = longBuf.remaining();
                longBuf.get(data, 0, pos);
            }
            System.out.println();
            for (int i = 0; i < pos; i++) {
                System.out.printf("%10d", data[i]);
            }
            buf.clear();
        }
        System.out.println("\nEOF reached.");
        inFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
        System.exit(1);
    }
}

From source file:BufferToText.java

public static void main(String[] args) throws Exception {
    FileChannel fc = new FileOutputStream("data2.txt").getChannel();
    fc.write(ByteBuffer.wrap("Some text".getBytes()));
    fc.close();/*from  ww  w.  ja va 2  s.c  o  m*/
    fc = new FileInputStream("data2.txt").getChannel();
    ByteBuffer buff = ByteBuffer.allocate(BSIZE);
    fc.read(buff);
    buff.flip();
    // Doesn't work:
    System.out.println(buff.asCharBuffer());
    // Decode using this system's default Charset:
    buff.rewind();
    String encoding = System.getProperty("file.encoding");
    System.out.println("Decoded using " + encoding + ": " + Charset.forName(encoding).decode(buff));
    // Or, we could encode with something that will print:
    fc = new FileOutputStream("data2.txt").getChannel();
    fc.write(ByteBuffer.wrap("Some text".getBytes("UTF-16BE")));
    fc.close();
    // Now try reading again:
    fc = new FileInputStream("data2.txt").getChannel();
    buff.clear();
    fc.read(buff);
    buff.flip();
    System.out.println(buff.asCharBuffer());
    // Use a CharBuffer to write through:
    fc = new FileOutputStream("data2.txt").getChannel();
    buff = ByteBuffer.allocate(24); // More than needed
    buff.asCharBuffer().put("Some text");
    fc.write(buff);
    fc.close();
    // Read and display:
    fc = new FileInputStream("data2.txt").getChannel();
    buff.clear();
    fc.read(buff);
    buff.flip();
    System.out.println(buff.asCharBuffer());
}

From source file:MainClass.java

public static void main(String[] args) {
    long[] primes = new long[] { 1, 2, 3, 5, 7 };
    File aFile = new File("C:/test/primes.txt");
    FileOutputStream outputFile = null;
    try {/*www . j a v  a2 s.c om*/
        outputFile = new FileOutputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel file = outputFile.getChannel();
    final int BUFFERSIZE = 100;
    ByteBuffer buf = ByteBuffer.allocate(BUFFERSIZE);
    DoubleBuffer doubleBuf = buf.asDoubleBuffer();
    buf.position(8);
    CharBuffer charBuf = buf.asCharBuffer();
    for (long prime : primes) {
        String primeStr = "prime = " + prime;
        doubleBuf.put(0, (double) primeStr.length());
        charBuf.put(primeStr);
        buf.position(2 * charBuf.position() + 8);
        LongBuffer longBuf = buf.asLongBuffer();
        longBuf.put(prime);
        buf.position(buf.position() + 8);
        buf.flip();
        try {
            file.write(buf);
        } catch (IOException e) {
            e.printStackTrace(System.err);
        }
        buf.clear();
        doubleBuf.clear();
        charBuf.clear();
    }
    try {
        System.out.println("File written is " + file.size() + "bytes.");
        outputFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}

From source file:MainClass.java

public static void main(String[] args) {
    File aFile = new File("primes.txt");
    FileInputStream inFile = null;
    try {/*  www  . ja v  a  2 s  . co  m*/
        inFile = new FileInputStream(aFile);
    } catch (FileNotFoundException e) {
        e.printStackTrace(System.err);
    }
    FileChannel inChannel = inFile.getChannel();
    try {
        ByteBuffer lengthBuf = ByteBuffer.allocate(8);
        while (true) {
            if (inChannel.read(lengthBuf) == -1) {
                break;
            }
            lengthBuf.flip();
            int strLength = (int) lengthBuf.getDouble();
            ByteBuffer buf = ByteBuffer.allocate(2 * strLength + 8);
            if (inChannel.read(buf) == -1) {
                break;
            }
            buf.flip();
            byte[] strChars = new byte[2 * strLength];
            buf.get(strChars);
            System.out.println(strLength);
            System.out.println(ByteBuffer.wrap(strChars).asCharBuffer());
            System.out.println(buf.getLong());
            lengthBuf.clear();
        }
        inFile.close();
    } catch (IOException e) {
        e.printStackTrace(System.err);
    }
}