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How do you send and receive UDP packets in Java on a multihomed machine?

I have a machine with VmWare installed which added two extra network interfaces. The OS is Vista. I have two Java applications, one which broadcasts datagrams, and one which receives those datagrams. The problem I’m having is that unless I disable both VmWare network interfaces, the receiver can’t receive the datagrams.

What is the best way to make that work without disabling the interfaces?

Answer

Look at the alternate constructor for DatagramSocket:

DatagramSocket(int port, InetAddress laddr)
Creates a datagram socket, bound to the specified local address.

I’m guessing you’re only specifying the port.

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Getting the ID of the element that fired an event

Is there any way to get the ID of the element that fires an event?

I’m thinking something like:

$(document).ready(function() {
  $("a").click(function() {
    var test = caller.id;
    alert(test.val());
  });
});
<script type="text/javascript" src="starterkit/jquery.js"></script>

<form class="item" id="aaa">
  <input class="title"></input>
</form>
<form class="item" id="bbb">
  <input class="title"></input>
</form>

Except of course that the var test should contain the id "aaa", if the event is fired from the first form, and "bbb", if the event is fired from the second form.

Answer

In jQuery event.target always refers to the element that triggered the event, where event is the parameter passed to the function. http://api.jquery.com/category/events/event-object/

$(document).ready(function() {
    $("a").click(function(event) {
        alert(event.target.id);
    });
});

Note also that this will also work, but that it is not a jQuery object, so if you wish to use a jQuery function on it then you must refer to it as $(this), e.g.:

$(document).ready(function() {
    $("a").click(function(event) {
        // this.append wouldn't work
        $(this).append(" Clicked");
    });
});
Categories
discuss

Video Thumbnails in Java

I want to generate a thumbnail preview of videos in Java. I’m mostly JMF and video manipulation alienated.

  • Is there an easy way to do it?
  • What about codecs? Will I have to deal with it?
  • Any video type is suported? (including Quicktime)

Answer

There seems to be a few examples out there that are far better than what I was going to send you.

See http://krishnabhargav.blogspot.com/2008/02/processing-videos-in-java.html.

I’d agree with Stu, however. If you can find a way to get what you want using some command-line tools (and run them using Commons-Exec), you might have a better overall solution than depending on what is essentially the Sanskrit of Java extensions.

Source: stackoverflow
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