What's your call?
 

A1 on the endline for a throwin (not an AP throwin). B1 jumps and reaches across the boundary line. Before I had a chance to blow my whistle for the violation he touches the ball on the out of bounds side of the boundary. The ball had left A1's hand but had not crossed the boundary line when contact was made.

Was this after a bucket?
If the player reached through, then touched the ball - delay or whack if second delay. If the player reached through and touched the ball - whack!

10-3-10
Reach through the throw-in boundary-line plane and touch or dislodge the ball as in 9-2 Penalty 3.

9-2 Penalty 3
If an opponent(s) for the thrower reaches through the throw-in boundary-line place and touches or dislodges the ball while in possession of the thrower or being passed to a teammate outside the boundary line (as in 7-5-7), a technical foul shall be charged to the offender. No warning for delay required.

Depends. Was it a throw in after a made basket?

Well, 9.2.10 states:

The opponent(s) of the thrower shall not have any part of his/her person through the inbounds side of the throw-in boundary-line plane until the ball has been released on a throw-in pass.

Then, under penalities:

3. If an opponent(s) of the thrower reaches through the throw-in boundary-line plane and touches or dislodges the ball while in possession of the thrower or being passed to a teammate outside the boundary line (as in 7.5.7), a technical foul shall be charged to the offender. No warning for delay required.

7.5.7 is a pass out of bounds from one player to another after a made basket which doesn't apply in your scenario in that your player is trying to inbound the ball.

Based on all of the above I believe you got no call since the ball's already been released before the contact is made.

You need to be a little more specific in order to get an accurate answer.

1. What type of throw-in was this?

2. Did the defender reach across the line BEFORE or AFTER the ball was released?

More Info
 

1.) This was not after a made basket. Just your garden variety throwin for causing the ball to go out-of-bounds.

2.) The defender reached across the boundary plane prior to the release of the ball.

Then, like tjones said, you have a delay-of-game warning, unless this was the second offense.

If the defender had waited until the ball had been released, then reached over and touched the ball, you would have nothing.

I think that's your answer. Violation of the throw-in plane. Since the violation occurs before the touching of the ball, no technical and issue a delay of game warning.

After the release, whether the ball is on the oob side or inbounds side ,no violation right?
Same for throw-in with end line priveleges ?

On any kind of throw in, there is no violation for a reach-over or touch after the ball is released.

UNLESS

It's an endline throw in after a made basket, and the thrower is passing the ball to a teammate who is also out of bounds. This is an automatic T. No warning required.

Right answer, wrong reasoning.
There's no technical foul because the ball was released before the defense touched it.
If, however, the defender reaches across and you cannot blow your whistle in time to prevent him from hitting the ball as its held by the thrower, it is a T even the first time. There's a case play (dang I hate leaving my book at work.)

Huh?

How is this:

Different reasoning than this:

Basically, if the ball has been released on a throw-in pass, the restrictions are no longer in place. If it has not (and this includes being passed between OOB teammates during an end line throwin), then all restrictions remain in place for the defense.

OK - let's get ultra-technical (no pun intended). It's still a DOG warning, except the second one results in a technical. Remember, if a defender reaches across and touches the ball before release, it's both a DOG warning and a technical. The reason this is the case is because if on the first time there's a technical for touching, it also counts as the first DOG warning so if there's just a subsequent reach across without touching, you get your second DOG warning and a T.

I hope that was clear. I just mean that the reaching that results in a technical for touching also counts as a DOG warning.

I wasn't clear, so I've highlighted the incorrect reasoning above.

This is the one play where you can ignore the fact that the ball was touched and simply issue a DOG warning. But, you're not really ignoring it, because it's not against the rules.

Otherwise, as I explained in my post, you can't ignore the technical just because a violation happened before it. If you don't blow your whistle before the defense touches the ball, you have to call the T. The reasoning rufus gave would lead one to believe the following scenario should result in only a DOG warning:

A1 with ball OOB for a throw-in.
B1 reaches across and swings his arms. Official tells him to knock it off. B1 then slaps the ball.

This is a T, regardless of whether a warning has been issued, and a warning is also issued if it has not been already.