V4LHalFilter.java :  » Messenger » hal4java » au » edu » jcu » haldbus » examples » Java Open Source

package au.edu.jcu.haldbus.examples;

import java.io.IOException;
import java.util.Map;

import au.edu.jcu.haldbus.HardwareWatcher;
import au.edu.jcu.haldbus.exceptions.AddRemoveElemException;
import au.edu.jcu.haldbus.exceptions.DBusException;
import au.edu.jcu.haldbus.filter.AbstractHalFilter;
import au.edu.jcu.haldbus.match.AlwaysMatch;
import au.edu.jcu.haldbus.match.GenericMatch;
import au.edu.jcu.haldbus.match.NextMatch;
import au.edu.jcu.haldbus.match.VectorMatch;

/**
 * This class is a good example of how to use the HAL java package. It defines a
 * client filter by extending {@link AbstractHalFilter}. It creates a list of
 * criteria matching V4L devices. When a V4L device is connected/disconnected,
 * it simply prints a line on the terminal.
 * 
 * @author gilles
 */
public class V4LHalFilter extends AbstractHalFilter {
  public static void main(String[] args) throws DBusException {
    // creates an instance of a HardwareWatcher
    HardwareWatcher w = new HardwareWatcher();

    // Instantiate our client
    V4LHalFilter v1 = new V4LHalFilter("Filter1");

    // Register it with the watcher
    w.addClient(v1);

    // start the watcher
    w.start();

    // Wait until we press enter
    System.out.println("Try connect / disconnect a v4l device");
    try {
      System.in.read();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }

    // stop the watcher
    w.stop();

    // remove our client
    w.removeClient(v1);
  }

  public V4LHalFilter(String n) throws AddRemoveElemException {
    super(n);

    // the calls to addMatch() below add new criteria
    // and assigns a name to each criterion

    // look for a property called 'info.capabilities' which contains a list of
    // strings.
    // if the list contains 'video4linux' then we have a match.
    addMatch("1-capability", new VectorMatch<String>("info.capabilities", "video4linux"));

    // look for a property called 'info.category'.
    // if it contains 'video4linux' we have a match.
    addMatch("2-category", new GenericMatch<String>("info.category", "video4linux"));

    // look for a property called 'info.capabilities' which contains a list of
    // strings.
    // if it contains 'video4linux.video_capture' then we have a match.
    addMatch("3-category.capture", new VectorMatch<String>("info.capabilities", "video4linux.video_capture"));

    // look for a property called 'video4linux.device'.
    // if it contains 'video' we have a match.
    addMatch("4-video4linux.device", new GenericMatch<String>("video4linux.device", "video", true, true));

    // look for a property called 'linux.device_file' and always match its value
    addMatch("5-deviceFile", new AlwaysMatch("linux.device_file"));

    // look for a property called 'info.parent'. Its value contains the UDI of
    // another object.
    // In that object, always match the value of the property 'info.product'
    addMatch("6-info.product", new NextMatch("@info.parent", new AlwaysMatch("info.product")));

    // look for a property called 'info.parent'. Its value contains the UDI of
    // another object.
    // In that object, always match the value of the property 'info.vendor'
    addMatch("7-info.vendor", new NextMatch("@info.parent", new AlwaysMatch("info.vendor")));
  }

  /**
   * this method is called when a device that matches the above criteria is
   * connected. the argument l is a map of critrion names and their values. The
   * names are the ones used when creating the list in the constructor. For
   * instance, if a Logitech webcam is plugged in and is assigned /dev/video0,
   * l.get("6-info.vendor") returns "046d" (the logitech PID) and
   * l.get("5-deviceFile") returns "/dev/video0"
   */
  @Override
  public void deviceAdded(Map<String, String> l) {
    System.out.println(l.get("6-info.product") + " - " + l.get("7-info.vendor") + " on " + l.get("5-deviceFile") + " Connected");
  }

  /**
   * this method is called when a device that matches the above criteria is
   * disconnected
   */
  @Override
  public void deviceRemoved(Map<String, String> l) {
    System.out.println(l.get("6-info.product") + " - " + l.get("7-info.vendor") + " on " + l.get("5-deviceFile") + " Disconnected");
  }
}