h1. Creating a custom PiecePicker

[[Creating a custom PiecePicker#Example-1|Example 1]] Creating a picker to prioritise the first piece in a file

h2. Example 1

<pre><code class="java">
public class MyPicker : PiecePicker {
    public MyPicker (PiecePicker basePicker)
        : base (basePicker)
    {

    }

    public override MessageBundle PickPiece(PeerId id, BitField peerBitfield, List<PeerId> otherPeers, int count, int startIndex, int endIndex)
    {
    // If we do not have the first piece and the other peer does have it
        if (!HaveFirstPieceAlready && peerBitfield[0] == true) {
            BitField bf = new BitField (peerBitfield.Length);
            bf [0] = true;
            MessageBundle msg = base.PickPiece (id, bf, otherPeers, count, startIndex, endIndex);
            if (msg != null)
                return msg;
        }
        return base.PickPiece (id, peerBitfield, otherPeers, count, startIndex, endIndex);
    }
}

// This picker can then be added to the default picking pipeline by doing:
torrentManager.ChangePicker (new MyPicker (torrentManager.CreateDefaultPicker ()));
</code></pre>