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package org.anjocaido.groupmanager.utils;

import java.util.Comparator;

/**
 *
 * @author gabrielcouto
 */
public class StringPermissionComparator implements Comparator<String> {

    private static StringPermissionComparator instance;

    public static StringPermissionComparator getInstance() {

        if (instance == null) {
            instance = new StringPermissionComparator();
        }
        return instance;
    }

    @Override
    public int compare(final String permA, final String permB) {
        final boolean ap = permA.startsWith("+");
        final boolean bp = permB.startsWith("+");
        final boolean am = permA.startsWith("-");
        final boolean bm = permB.startsWith("-");
        if (ap && bp) {
            return 0;
        }
        if (ap && !bp) {
            return -1;
        }
        if (!ap && bp) {
            return 1;
        }
        if (am && bm) {
            return 0;
        }
        if (am && !bm) {
            return -1;
        }
        if (!am && bm) {
            return 1;
        }
        return permA.compareToIgnoreCase(permB);
    }
}