List of usage examples for java.nio ByteBuffer position
public final Buffer position(int newPosition)
From source file:Main.java
public static void main(String[] argv) throws Exception { ByteBuffer byteBuffer = ByteBuffer.allocate(7).order(ByteOrder.BIG_ENDIAN); CharBuffer charBuffer = byteBuffer.asCharBuffer(); byteBuffer.put(0, (byte) 0); byteBuffer.put(1, (byte) 'H'); byteBuffer.put(2, (byte) 0); byteBuffer.put(3, (byte) 'i'); byteBuffer.put(4, (byte) 0); byteBuffer.put(5, (byte) '!'); byteBuffer.put(6, (byte) 0); println(byteBuffer);/*from www . j a v a 2 s. c om*/ println(charBuffer); // now slice it differently byteBuffer.position(4); charBuffer = byteBuffer.asCharBuffer(); println(byteBuffer); println(charBuffer); }
From source file:UDPTimeServer.java
public static void main(String[] args) throws IOException { int port = 37; ByteBuffer in = ByteBuffer.allocate(8192); ByteBuffer out = ByteBuffer.allocate(8); out.order(ByteOrder.BIG_ENDIAN); SocketAddress address = new InetSocketAddress(port); DatagramChannel channel = DatagramChannel.open(); DatagramSocket socket = channel.socket(); socket.bind(address);/*www. j a v a 2 s.c o m*/ System.err.println("bound to " + address); while (true) { try { in.clear(); SocketAddress client = channel.receive(in); System.err.println(client); long secondsSince1970 = System.currentTimeMillis(); out.clear(); out.putLong(secondsSince1970); out.flip(); out.position(4); channel.send(out, client); } catch (Exception ex) { System.err.println(ex); } } }
From source file:CTmousetrack.java
public static void main(String[] args) { String outLoc = new String("." + File.separator + "CTdata"); // Location of the base output data folder; only used when writing out CT data to a local folder String srcName = "CTmousetrack"; // name of the output CT source long blockPts = 10; // points per block flush long sampInterval = 10; // time between sampling updates, msec double trimTime = 0.0; // amount of data to keep (trim time), sec boolean debug = false; // turn on debug? // Specify the CT output connection CTWriteMode writeMode = CTWriteMode.LOCAL; // The selected mode for writing out CT data String serverHost = ""; // Server (FTP or HTTP/S) host:port String serverUser = ""; // Server (FTP or HTTPS) username String serverPassword = ""; // Server (FTP or HTTPS) password // For UDP output mode DatagramSocket udpServerSocket = null; InetAddress udpServerAddress = null; String udpHost = ""; int udpPort = -1; // Concatenate all of the CTWriteMode types String possibleWriteModes = ""; for (CTWriteMode wm : CTWriteMode.values()) { possibleWriteModes = possibleWriteModes + ", " + wm.name(); }/*from w w w .jav a 2s. c o m*/ // Remove ", " from start of string possibleWriteModes = possibleWriteModes.substring(2); // // Argument processing using Apache Commons CLI // // 1. Setup command line options Options options = new Options(); options.addOption("h", "help", false, "Print this message."); options.addOption(Option.builder("o").argName("base output dir").hasArg().desc( "Base output directory when writing data to local folder (i.e., this is the location of CTdata folder); default = \"" + outLoc + "\".") .build()); options.addOption(Option.builder("s").argName("source name").hasArg() .desc("Name of source to write data to; default = \"" + srcName + "\".").build()); options.addOption(Option.builder("b").argName("points per block").hasArg() .desc("Number of points per block; UDP output mode will use 1 point/block; default = " + Long.toString(blockPts) + ".") .build()); options.addOption(Option.builder("dt").argName("samp interval msec").hasArg() .desc("Sampling period in msec; default = " + Long.toString(sampInterval) + ".").build()); options.addOption(Option.builder("t").argName("trim time sec").hasArg().desc( "Trim (ring-buffer loop) time (sec); this is only used when writing data to local folder; specify 0 for indefinite; default = " + Double.toString(trimTime) + ".") .build()); options.addOption( Option.builder("w").argName("write mode").hasArg() .desc("Type of write connection; one of " + possibleWriteModes + "; all but UDP mode write out to CT; default = " + writeMode.name() + ".") .build()); options.addOption(Option.builder("host").argName("host[:port]").hasArg() .desc("Host:port when writing via FTP, HTTP, HTTPS, UDP.").build()); options.addOption(Option.builder("u").argName("username,password").hasArg() .desc("Comma-delimited username and password when writing to CT via FTP or HTTPS.").build()); options.addOption("x", "debug", false, "Enable CloudTurbine debug output."); // 2. Parse command line options CommandLineParser parser = new DefaultParser(); CommandLine line = null; try { line = parser.parse(options, args); } catch (ParseException exp) { // oops, something went wrong System.err.println("Command line argument parsing failed: " + exp.getMessage()); return; } // 3. Retrieve the command line values if (line.hasOption("help")) { // Display help message and quit HelpFormatter formatter = new HelpFormatter(); formatter.setWidth(120); formatter.printHelp("CTmousetrack", "", options, "NOTE: UDP output is a special non-CT output mode where single x,y points are sent via UDP to the specified host:port."); return; } outLoc = line.getOptionValue("o", outLoc); if (!outLoc.endsWith("\\") && !outLoc.endsWith("/")) { outLoc = outLoc + File.separator; } // Make sure the base output folder location ends in "CTdata" if (!outLoc.endsWith("CTdata\\") && !outLoc.endsWith("CTdata/")) { outLoc = outLoc + "CTdata" + File.separator; } srcName = line.getOptionValue("s", srcName); blockPts = Long.parseLong(line.getOptionValue("b", Long.toString(blockPts))); sampInterval = Long.parseLong(line.getOptionValue("dt", Long.toString(sampInterval))); trimTime = Double.parseDouble(line.getOptionValue("t", Double.toString(trimTime))); // Type of output connection String writeModeStr = line.getOptionValue("w", writeMode.name()); boolean bMatch = false; for (CTWriteMode wm : CTWriteMode.values()) { if (wm.name().toLowerCase().equals(writeModeStr.toLowerCase())) { writeMode = wm; bMatch = true; } } if (!bMatch) { System.err.println("Unrecognized write mode, \"" + writeModeStr + "\"; write mode must be one of " + possibleWriteModes); System.exit(0); } if (writeMode != CTWriteMode.LOCAL) { // User must have specified the host // If FTP or HTTPS, they may also specify username/password serverHost = line.getOptionValue("host", serverHost); if (serverHost.isEmpty()) { System.err.println( "When using write mode \"" + writeModeStr + "\", you must specify the server host."); System.exit(0); } if (writeMode == CTWriteMode.UDP) { // Force blockPts to be 1 blockPts = 1; // User must have specified both host and port int colonIdx = serverHost.indexOf(':'); if ((colonIdx == -1) || (colonIdx >= serverHost.length() - 1)) { System.err.println( "For UDP output mode, both the host and port (<host>:<port>)) must be specified."); System.exit(0); } udpHost = serverHost.substring(0, colonIdx); String udpPortStr = serverHost.substring(colonIdx + 1); try { udpPort = Integer.parseInt(udpPortStr); } catch (NumberFormatException nfe) { System.err.println("The UDP port must be a positive integer."); System.exit(0); } } if ((writeMode == CTWriteMode.FTP) || (writeMode == CTWriteMode.HTTPS)) { String userpassStr = line.getOptionValue("u", ""); if (!userpassStr.isEmpty()) { // This string should be comma-delimited username and password String[] userpassCSV = userpassStr.split(","); if (userpassCSV.length != 2) { System.err.println("When specifying a username and password for write mode \"" + writeModeStr + "\", separate the username and password by a comma."); System.exit(0); } serverUser = userpassCSV[0]; serverPassword = userpassCSV[1]; } } } debug = line.hasOption("debug"); System.err.println("CTmousetrack parameters:"); System.err.println("\toutput mode = " + writeMode.name()); if (writeMode == CTWriteMode.UDP) { System.err.println("\twrite to " + udpHost + ":" + udpPort); } else { System.err.println("\tsource = " + srcName); System.err.println("\ttrim time = " + trimTime + " sec"); } System.err.println("\tpoints per block = " + blockPts); System.err.println("\tsample interval = " + sampInterval + " msec"); try { // // Setup CTwriter or UDP output // CTwriter ctw = null; CTinfo.setDebug(debug); if (writeMode == CTWriteMode.LOCAL) { ctw = new CTwriter(outLoc + srcName, trimTime); System.err.println("\tdata will be written to local folder \"" + outLoc + "\""); } else if (writeMode == CTWriteMode.FTP) { CTftp ctftp = new CTftp(srcName); try { ctftp.login(serverHost, serverUser, serverPassword); } catch (Exception e) { throw new IOException( new String("Error logging into FTP server \"" + serverHost + "\":\n" + e.getMessage())); } ctw = ctftp; // upcast to CTWriter System.err.println("\tdata will be written to FTP server at " + serverHost); } else if (writeMode == CTWriteMode.HTTP) { // Don't send username/pw in HTTP mode since they will be unencrypted CThttp cthttp = new CThttp(srcName, "http://" + serverHost); ctw = cthttp; // upcast to CTWriter System.err.println("\tdata will be written to HTTP server at " + serverHost); } else if (writeMode == CTWriteMode.HTTPS) { CThttp cthttp = new CThttp(srcName, "https://" + serverHost); // Username/pw are optional for HTTPS mode; only use them if username is not empty if (!serverUser.isEmpty()) { try { cthttp.login(serverUser, serverPassword); } catch (Exception e) { throw new IOException(new String( "Error logging into HTTP server \"" + serverHost + "\":\n" + e.getMessage())); } } ctw = cthttp; // upcast to CTWriter System.err.println("\tdata will be written to HTTPS server at " + serverHost); } else if (writeMode == CTWriteMode.UDP) { try { udpServerSocket = new DatagramSocket(); } catch (SocketException se) { System.err.println("Error creating socket for UDP:\n" + se); System.exit(0); } try { udpServerAddress = InetAddress.getByName(udpHost); } catch (UnknownHostException uhe) { System.err.println("Error getting UDP server host address:\n" + uhe); System.exit(0); } } if (writeMode != CTWriteMode.UDP) { ctw.setBlockMode(blockPts > 1, blockPts > 1); ctw.autoFlush(0); // no autoflush ctw.autoSegment(1000); } // screen dims Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); double width = screenSize.getWidth(); double height = screenSize.getHeight(); // use Map for consolidated putData Map<String, Object> cmap = new LinkedHashMap<String, Object>(); // loop and write some output for (int i = 0; i < 1000000; i++) { // go until killed long currentTime = System.currentTimeMillis(); Point mousePos = MouseInfo.getPointerInfo().getLocation(); float x_pt = (float) (mousePos.getX() / width); // normalize float y_pt = (float) ((height - mousePos.getY()) / height); // flip Y (so bottom=0) if (writeMode != CTWriteMode.UDP) { // CT output mode ctw.setTime(currentTime); cmap.clear(); cmap.put("x", x_pt); cmap.put("y", y_pt); ctw.putData(cmap); if (((i + 1) % blockPts) == 0) { ctw.flush(); System.err.print("."); } } else { // UDP output mode // We force blockPts to be 1 for UDP output mode, i.e. we "flush" the data every time // Write the following data (21 bytes total): // header = "MOUSE", 5 bytes // current time, long, 8 bytes // 2 floats (x,y) 4 bytes each, 8 bytes int len = 21; ByteBuffer bb = ByteBuffer.allocate(len); String headerStr = "MOUSE"; bb.put(headerStr.getBytes("UTF-8")); bb.putLong(currentTime); bb.putFloat(x_pt); bb.putFloat(y_pt); // Might be able to use the following, but not sure: // byte[] sendData = bb.array(); byte[] sendData = new byte[len]; bb.position(0); bb.get(sendData, 0, len); DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, udpServerAddress, udpPort); try { udpServerSocket.send(sendPacket); } catch (IOException e) { System.err.println("Test server caught exception trying to send data to UDP client:\n" + e); } System.err.print("."); } try { Thread.sleep(sampInterval); } catch (Exception e) { } ; } if (writeMode != CTWriteMode.UDP) { ctw.flush(); // wrap up } } catch (Exception e) { System.err.println("CTmousetrack exception: " + e); e.printStackTrace(); } }
From source file:HttpGet.java
public static void main(String[] args) { SocketChannel server = null; // Channel for reading from server FileOutputStream outputStream = null; // Stream to destination file WritableByteChannel destination; // Channel to write to it try { // Exception handling and channel closing code follows this block // Parse the URL. Note we use the new java.net.URI, not URL here. URI uri = new URI(args[0]); // Now query and verify the various parts of the URI String scheme = uri.getScheme(); if (scheme == null || !scheme.equals("http")) throw new IllegalArgumentException("Must use 'http:' protocol"); String hostname = uri.getHost(); int port = uri.getPort(); if (port == -1) port = 80; // Use default port if none specified String path = uri.getRawPath(); if (path == null || path.length() == 0) path = "/"; String query = uri.getRawQuery(); query = (query == null) ? "" : '?' + query; // Combine the hostname and port into a single address object. // java.net.SocketAddress and InetSocketAddress are new in Java 1.4 SocketAddress serverAddress = new InetSocketAddress(hostname, port); // Open a SocketChannel to the server server = SocketChannel.open(serverAddress); // Put together the HTTP request we'll send to the server. String request = "GET " + path + query + " HTTP/1.1\r\n" + // The request "Host: " + hostname + "\r\n" + // Required in HTTP 1.1 "Connection: close\r\n" + // Don't keep connection open "User-Agent: " + HttpGet.class.getName() + "\r\n" + "\r\n"; // Blank // line // indicates // end of // request // headers // Now wrap a CharBuffer around that request string CharBuffer requestChars = CharBuffer.wrap(request); // Get a Charset object to encode the char buffer into bytes Charset charset = Charset.forName("ISO-8859-1"); // Use the charset to encode the request into a byte buffer ByteBuffer requestBytes = charset.encode(requestChars); // Finally, we can send this HTTP request to the server. server.write(requestBytes);//from w w w.j a va2s. c om // Set up an output channel to send the output to. if (args.length > 1) { // Use a specified filename outputStream = new FileOutputStream(args[1]); destination = outputStream.getChannel(); } else // Or wrap a channel around standard out destination = Channels.newChannel(System.out); // Allocate a 32 Kilobyte byte buffer for reading the response. // Hopefully we'll get a low-level "direct" buffer ByteBuffer data = ByteBuffer.allocateDirect(32 * 1024); // Have we discarded the HTTP response headers yet? boolean skippedHeaders = false; // The code sent by the server int responseCode = -1; // Now loop, reading data from the server channel and writing it // to the destination channel until the server indicates that it // has no more data. while (server.read(data) != -1) { // Read data, and check for end data.flip(); // Prepare to extract data from buffer // All HTTP reponses begin with a set of HTTP headers, which // we need to discard. The headers end with the string // "\r\n\r\n", or the bytes 13,10,13,10. If we haven't already // skipped them then do so now. if (!skippedHeaders) { // First, though, read the HTTP response code. // Assume that we get the complete first line of the // response when the first read() call returns. Assume also // that the first 9 bytes are the ASCII characters // "HTTP/1.1 ", and that the response code is the ASCII // characters in the following three bytes. if (responseCode == -1) { responseCode = 100 * (data.get(9) - '0') + 10 * (data.get(10) - '0') + 1 * (data.get(11) - '0'); // If there was an error, report it and quit // Note that we do not handle redirect responses. if (responseCode < 200 || responseCode >= 300) { System.err.println("HTTP Error: " + responseCode); System.exit(1); } } // Now skip the rest of the headers. try { for (;;) { if ((data.get() == 13) && (data.get() == 10) && (data.get() == 13) && (data.get() == 10)) { skippedHeaders = true; break; } } } catch (BufferUnderflowException e) { // If we arrive here, it means we reached the end of // the buffer and didn't find the end of the headers. // There is a chance that the last 1, 2, or 3 bytes in // the buffer were the beginning of the \r\n\r\n // sequence, so back up a bit. data.position(data.position() - 3); // Now discard the headers we have read data.compact(); // And go read more data from the server. continue; } } // Write the data out; drain the buffer fully. while (data.hasRemaining()) destination.write(data); // Now that the buffer is drained, put it into fill mode // in preparation for reading more data into it. data.clear(); // data.compact() also works here } } catch (Exception e) { // Report any errors that arise System.err.println(e); System.err.println("Usage: java HttpGet <URL> [<filename>]"); } finally { // Close the channels and output file stream, if needed try { if (server != null && server.isOpen()) server.close(); if (outputStream != null) outputStream.close(); } catch (IOException e) { } } }
From source file:Main.java
protected static ByteBuffer renewBuffer(ByteBuffer buf) { buf.position(0); buf.limit(buf.capacity()); return buf; }
From source file:Main.java
/** * continue writing to bb starting from its current limit. * /*from w w w . jav a 2 s . com*/ * @param bb */ public static void extend(ByteBuffer bb) { bb.position(bb.limit()).limit(bb.capacity()); }
From source file:Main.java
static void memcpy(ByteBuffer dstBuffer, int dstByteOffset, ByteBuffer srcBuffer, int srcByteOffset, int length) { ByteBuffer dstDup = dstBuffer.duplicate(); dstDup.position(dstByteOffset); dstDup.limit(dstByteOffset + length); ByteBuffer srcDup = srcBuffer.duplicate(); srcDup.position(srcByteOffset);/*from w ww . j ava 2 s . c o m*/ srcDup.limit(srcByteOffset + length); dstDup.put(srcDup); }
From source file:Main.java
public static ByteBuffer makeByteBuffer(int size) { ByteBuffer bb = ByteBuffer.allocateDirect(size); bb.position(0); return bb;/*from www . j av a 2s . co m*/ }
From source file:Main.java
/** * // w w w .j av a 2 s.c o m * @param arr * @return */ public static final ByteBuffer createByteBuffer(byte[] arr) { int len = sizeofB(arr.length); ByteBuffer bb = ByteBuffer.allocateDirect(len); bb.order(ByteOrder.nativeOrder()); ByteBuffer fb = bb; fb.put(arr); fb.position(0); return fb; }
From source file:Main.java
public static ByteBuffer makeByteBuffer(byte[] i_arr) { ByteBuffer bb = ByteBuffer.allocateDirect(i_arr.length); bb.put(i_arr);/*from w w w . j av a2 s. co m*/ bb.position(0); return bb; }