package org.slf4j.profiler;
import java.util.ArrayList;
import java.util.Arrays;
public class SortAndPruneComposites {
static String NESTED_PROFILER_NAME = "SORT_AND_PRUNE";
final int[] originalArray;
final int originalArrrayLength;
public SortAndPruneComposites(int[] randomArray) {
this.originalArray = randomArray;
this.originalArrrayLength = randomArray.length;
}
public int[] sortAndPruneComposites() {
// retrieve previously registered profiler named "SORT_AND_PRUNE"
ProfilerRegistry profilerRegistry = ProfilerRegistry.getThreadContextInstance();
Profiler sortProfiler = profilerRegistry.get(NESTED_PROFILER_NAME);
// start a new stopwatch called SORT
sortProfiler.start("SORT");
int[] sortedArray = sort();
// start a new stopwatch called PRUNE_COMPOSITES
sortProfiler.start("PRUNE_COMPOSITES");
int result[] = pruneComposites(sortedArray);
return result;
}
private int[] sort() {
int[] sortedArray = new int[originalArrrayLength];
System.arraycopy(originalArray, 0, sortedArray, 0, originalArrrayLength);
Arrays.sort(sortedArray);
return sortedArray;
}
int[] pruneComposites(int[] sortedArray) {
ArrayList<Integer> primesArray = new ArrayList<Integer>();
for(int i = 0; i < originalArrrayLength; i++) {
int n = sortedArray[i];
if(isPrime(n)) {
primesArray.add(n);
}
}
int resultSize = primesArray.size();
int[] result = new int[resultSize];
for(int i = 0; i < resultSize; i++) {
result[i] = primesArray.get(i);
}
return result;
}
public boolean isPrime(int n) {
if(n < 2) {
return false;
}
if(n%2 == 0) {
return false;
}
for(int i = 3; i*i <=n; i += 2) {
if(n%i ==0) {
return false;
}
}
return true;
}
}