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POSensorEventListener and Timer-thread using shared Vector
 

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  1. POSensorEventListener and Timer-thread using shared Vector
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    <p>What is the best way to handle competing threads that are reading data from a vector?</p> <p>I'm trying to write an android app where I'm trying to read sensor data periodically and write it to a file and then upload the file to a remote server. </p> <p>What I do as the first step, I register the SensorEventListener for each sensor and then, whenever sensor values change, I push new values to a <code>Vector()</code>. Here <code>data</code> is a vector of user defined object.</p> <pre><code>@Override // when sensor value is changed, this method will be called. public void onSensorChanged(SensorEvent event) { synchronized (this){ Datapoint dp=new Datapoint(event.sensor.getType(),event.values); data.add(dp); } } </code></pre> <p>As the next step I use a <code>Timer</code> object to periodically read off data from the <code>data</code> vector and send it to a remote server. </p> <pre><code>class calculateSensorData extends TimerTask { public synchronized void run() { for (Datapoint item : data) { //use data } data.clear(); } } </code></pre> <p>The main problem is when I try to access the data vector inside the <code>TimerTask</code> I get <code>java.util.ConcurrentModficiationException</code>. </p> <p>I think this is because both the sensor listener thread and timer thread are trying to update/modify the shared Vector at the same time. </p> <p>I got around the problem by un-registering the listeners at the start of the <code>Timer</code> task. But that not a good solution. </p> <p>Any other way to accomplish this without un-registering and re-registering all sensor listeners each time the <code>Timer</code> fires.</p>
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    1. COarent Vectors synchronized..
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    2. COThat is what I thought too. But don't know why this is happening. (For redundancy I even tried the synchronized methods at shown in the post)
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