http://bugswarm.net/docs/write-a-swarm-enabled-app

gistfile1.java

package earthquake_detector;
import java.util.Map;

import com.buglabs.bug.module.gps.pub.IPositionProvider;
import com.buglabs.bug.swarm.connector.pub.ISyncFilter;

/**
 * Given a previous sample and the current sample, determine if the difference is great enough to pass data to the server.
 * 
 * @author kgilmer
 *
 */
public class AccelerometerSampleFilter implements ISyncFilter {

	private float lx, ly, lz;
	private final IPositionProvider positionProvider;
	
	public AccelerometerSampleFilter(IPositionProvider positionProvider) {
		this.positionProvider = positionProvider;
		lx = 0;
		ly = 0;
		lz = 0;
	}
	
	@Override
	public boolean synchronize(Map model, Object[] keys) {
		boolean retVal = false;
		
		float ac[] = (float []) model.get(Activator.KEY_ACCELERATION);
		
		if (ac == null) {
			return false;
		}
		
		if (deviates(lx, ac[0], 1) || deviates(ly, ac[1], 1) || deviates(lz, ac[2], 1)) {
			//Add our current location in since we'll be sending event data to the server.
			model.put(Activator.KEY_LOCATION, Monitor.positionAsArray(positionProvider.getPosition()));
			retVal = true;
		}
		
		lx = ac[0];
		ly = ac[1];
		lz = ac[2];
		
		return retVal;
	}
	
	private boolean deviates(float src, float target, float delta) {
		return Math.abs(src - target) > delta;
	}

}