Could someone explain it to me?
package com.codegym.task.task22.task2208;
import java.util.HashMap;
import java.util.Map;
/*
Build a WHERE query
*/
public class Solution {
public static void main(String[] args) {
Map<String, String> map = new HashMap<>();
map.put("name", null);
map.put("country", null);
map.put("city", null);
map.put("age", null);
System.out.println(getQuery(map));
}
public static String getQuery(Map<String, String> params) {
StringBuilder sb = new StringBuilder();
String name = params.get("name");
String country = params.get("country");
String city = params.get("city");
String age = params.get("age");
if (name != null)
sb.append("name = '").append(name).append("' and ");
if (country != null)
sb.append("country = '").append(country).append("' and ");
if (city != null)
sb.append("city = '").append(city).append("' and ");
if (age != null)
sb.append("age = '").append(age).append("'");
if (sb.length() != 0 && sb.charAt(sb.length() - 1) != '\'')
sb.setLength(sb.length() - 5);
return sb.toString();
}
}