SPLat.java

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
/**
 * 
 * Original implementation by 
 * Kim et al. SPLat: Lightweight dynamic analysis for reducing combinatorics in testing configurable systems
 * 
 * @author Jens Meinicke
 *
 */
public class SPLat {

	public static void main(String[] args) {
		int runs = 0;
		System.out.println("---------------------- run nr. " + ++runs);
		new SPLat().method2();
		
		while (!missingConfigurations.isEmpty()) {
			System.out.println("---------------------- run nr. " + ++runs);
//			currentConfiguration = missingConfigurations.remove(0);
//			currentConfiguration = missingConfigurations.remove(missingConfigurations.size() - 1);
			currentConfiguration = missingConfigurations.removeLast();
			new SPLat().method2();
		}
		System.out.println("finished after " + runs + " configurations");
	}
	static final int nrFeatures = 20;
	
	static LinkedList<Configuration> missingConfigurations = new LinkedList<>();
	
	static Configuration currentConfiguration = new Configuration();
	
	void method() {
		int i = 0;
		if (get(0)) {
			
			if (get(1)) {
				if (get(2)) {
					
				}
				
			}
		}

		System.out.println(i);
		System.out.println(currentConfiguration);
	}
	
	
	void method2() {
		int i = 0;

		if (get(1)) {i++;}
		if (get(1)) {i++;} 
		if (get(2)) {i++;} 
		if (get(3)) {i++;} 
		if (get(4)) {i++;} 
		if (get(5)) {i++;} 
		if (get(6)) {i++;} 
		if (get(7)) {i++;} 
		if (get(8)) {i++;} 
		if (get(9)) {i++;} 
		if (get(10)){i++;} 
		if (get(11)){i++;} 
		if (get(12)){i++;} 
		if (get(13)){i++;} 
		if (get(14)){i++;} 
		if (get(15)){i++;} 
		if (get(16)){i++;} 
		if (get(17)){i++;} 
		if (get(18)){i++;} 
//		if (get(19)){i++;} 
//		if (get(20)){i++;} 
//		if (get(21)){i++;} 
//		if (get(22)){i++;}
		
//		System.out.println(i);
//		System.out.println(currentConfiguration);
		System.out.println(missingConfigurations.size());
	}
	private boolean get(int i) {
		byte selection = currentConfiguration.get(i);
		if (selection == 0) {
			currentConfiguration.set(i, (byte) 1);
			Configuration newConfig = currentConfiguration.copy();
			
			newConfig.set(i, (byte)-1);
			missingConfigurations.add(newConfig);
		}
		
		return currentConfiguration.get(i) == 1;
	}

}
class Configuration {
	byte[] selection = new byte[SPLat.nrFeatures];
	byte get(int i) {
		return selection[i];
	}
	void set(int i, byte j) {
		selection[i] = j;
	}
	
	Configuration copy() {
		Configuration c = new Configuration();
		for (int k = 0; k < selection.length; k++) {
			if (selection[k] != 0) {
				c.selection[k] = selection[k];
			}
		}
		return c;
	}
	
	@Override
	public int hashCode() {
		int hash = 0;
		for (int j = 0; j < selection.length; j++) {
			if (selection[j] != 0 && selection[j] == 1) {
				hash += Math.pow(2, j);
			}
		}
		return hash;
	}
	@Override
	public boolean equals(Object obj) {
		Configuration other = (Configuration) obj;
		return Arrays.equals(selection, other.selection);
	}
	
	@Override
	public String toString() {
		return Arrays.toString(selection);
	}
}