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leJOS (pronounced like the Spanish word "lejos" for "far") is a tiny Java Virtual Machine. In 2013 it was ported to the LEGO EV3 brick.

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package lejos.robotics;

/** Abstraction for classes that fetch samples from a sensor and classes that are able to process samples.
   
 * A sample is a measurement taken by a sensor at a single moment in time. 
 * A sample can have one or more elements. The number of elements in a sample depends on the sensor (and sensor mode). 
 * 

 * 
 * Sample providers comply with standards.
 * 
 * 
 * Sample providers use standard units.

 * 
 * Length in meters
 * Angle in degrees
 * Temperature in degrees celcius
 * Pressure in Pascal
 * Speed in m/s
 * Acceleration in m/s^2
 * etc...
 * 
 * 
 * 
 * When there is no clear unit a sample provider use normalized values in the range between 0 and 1.
 * 
 * 
 * Sample providers that measure spatial data use a right handed cartesian coordinate system with the X-axis pointing forwards, 
 * the Y-axis pointing to the left and the Z-axis pointing up. 
 * (The plug of a sensor is always on its back.)
 * 
 * 
 * A positive rotation of a mobile robot is a counterclockwise rotation. 
 * 
 * 
 * If a sample provider measures spatial data over more than one axis, the order of the elements in a sample corresponds with the X,Y and Z axis.
 * 
 * 
 * @author Aswin Bouwmeester
 *
 */
public interface SampleProvider {
	
	/** Returns the number of elements in a sample.

	 * The number of elements does not change during runtime.
	 * @return
	 * the number of elements in a sample
	 */
	public int sampleSize();
	
	/** Fetches a sample from a sensor or filter.
	 * @param sample
	 * The array to store the sample in. 
	 * @param offset
	 * The elements of the sample are stored in the array starting at the offset position.
	 */
	public void fetchSample(float[] sample, int offset);
}