    001/**
    002 * Copyright (c) 2004-2011 QOS.ch
    003 * All rights reserved.
    004 *
    005 * Permission is hereby granted, free  of charge, to any person obtaining
    006 * a  copy  of this  software  and  associated  documentation files  (the
    007 * "Software"), to  deal in  the Software without  restriction, including
    008 * without limitation  the rights to  use, copy, modify,  merge, publish,
    009 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
    010 * permit persons to whom the Software  is furnished to do so, subject to
    011 * the following conditions:
    012 *
    013 * The  above  copyright  notice  and  this permission  notice  shall  be
    014 * included in all copies or substantial portions of the Software.
    015 *
    016 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
    017 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
    018 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
    019 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
    020 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    021 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
    022 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    023 *
    024 */
    025package org.slf4j.profiler;
    026
    027import java.util.ArrayList;
    028import java.util.Arrays;
    029
    030public class SortAndPruneComposites {
    031
    032    static String NESTED_PROFILER_NAME = "SORT_AND_PRUNE";
    033
    034    final int[] originalArray;
    035    final int originalArrrayLength;
    036
    037    public SortAndPruneComposites(int[] randomArray) {
    038        this.originalArray = randomArray;
    039        this.originalArrrayLength = randomArray.length;
    040
    041    }
    042
    043    public int[] sortAndPruneComposites() {
    044        // retrieve previously registered profiler named "SORT_AND_PRUNE"
    045        ProfilerRegistry profilerRegistry = ProfilerRegistry.getThreadContextInstance();
    046        Profiler sortProfiler = profilerRegistry.get(NESTED_PROFILER_NAME);
    047
    048        // start a new stopwatch called SORT
    049        sortProfiler.start("SORT");
    050        int[] sortedArray = sort();
    051        // start a new stopwatch called PRUNE_COMPOSITES
    052        sortProfiler.start("PRUNE_COMPOSITES");
    053        int result[] = pruneComposites(sortedArray);
    054
    055        return result;
    056    }
    057
    058    private int[] sort() {
    059        int[] sortedArray = new int[originalArrrayLength];
    060        System.arraycopy(originalArray, 0, sortedArray, 0, originalArrrayLength);
    061        Arrays.sort(sortedArray);
    062        return sortedArray;
    063    }
    064
    065    int[] pruneComposites(int[] sortedArray) {
    066        ArrayList<Integer> primesArray = new ArrayList<Integer>();
    067        for (int i = 0; i < originalArrrayLength; i++) {
    068            int n = sortedArray[i];
    069            if (isPrime(n)) {
    070                primesArray.add(n);
    071            }
    072        }
    073        int resultSize = primesArray.size();
    074        int[] result = new int[resultSize];
    075
    076        for (int i = 0; i < resultSize; i++) {
    077            result[i] = primesArray.get(i);
    078        }
    079        return result;
    080    }
    081
    082    public boolean isPrime(int n) {
    083        if (n < 2) {
    084            return false;
    085        }
    086        if (n % 2 == 0) {
    087            return false;
    088        }
    089        for (int i = 3; i * i <= n; i += 2) {
    090            if (n % i == 0) {
    091                return false;
    092            }
    093        }
    094        return true;
    095    }
    096}