toLowerCase and toUpperCase methods for Azerbaijanian chars

AzerbaijanianAlphabetProcessor.class

import java.util.HashMap;
import java.util.Map;

/**
 * toLowerCase and toUpperCase methods for
 * Azerbaijanian chars
 *
 * 2 iyul, 2018
 *
 *  * @author ramiz.demiurge
 */
public class AzerbaijanianAlphabetProcessor {
    private static final Map<String, String> values;

    static {
        values = new HashMap<>();
        values.put("Ü", "ü");
        values.put("Ə", "ə");
        values.put("Ö", "ö");
        values.put("İ", "i");
        values.put("Ğ", "ğ");
        values.put("I", "ı");
        values.put("Ş", "ş");
        values.put("Ç", "ç");
    }

    public String toLowerCase(String content) {
        String words[] = content.split("");
        for (int i = 0; i < words.length; i++) {
            String temp = values.get(words[i]);
            if (temp != null) {
                words[i] = temp;
            } else {
                boolean lower = false;
                for (Map.Entry<String, String> entry : values.entrySet()) {
                    if (words[i].equals(entry.getValue())) {
                        lower = true;
                        break;
                    }
                }
                if (!lower) {
                    words[i] = words[i].toLowerCase();
                }
            }
        }
        StringBuilder builder = new StringBuilder();
        for (String s : words) {
            builder.append(s);
        }
        return builder.toString();
    }

    public String toUpperCase(String content) {
        String words[] = content.split("");
        for (int i = 0; i < words.length; i++) {
            boolean found = false;
            for (Map.Entry<String, String> entry : values.entrySet()) {
                if(entry.getValue().equals(words[i])){
                    words[i] = entry.getKey();
                    found = true;
                    break;
                }
            }

            if(found) continue;

            if (values.get(words[i]) == null){
                words[i] = words[i].toUpperCase();
            }
        }
        StringBuilder builder = new StringBuilder();
        for (String s : words) {
            builder.append(s);
        }
        return builder.toString();
    }

}

AzerbaijanianAlphabetProcessorTest.class

import org.junit.Assert;
import org.junit.Test;

public class AzerbaijanianAlphabetProcessorTest {

    @Test
    public void toLowerCase() {
        AzerbaijanianAlphabetProcessor azerbaijanianAlphabeteProcessor = new AzerbaijanianAlphabetProcessor();

        String actual = azerbaijanianAlphabeteProcessor.toLowerCase("MƏHSULUN TƏTBİQ EDİLİB ÜZƏ GƏTİRİLMƏSİ.");
        String expected = "məhsulun tətbiq edilib üzə gətirilməsi.";

        System.out.println(actual);

        Assert.assertEquals(expected,actual);
    }

    @Test
    public void toUpperCase() {
        AzerbaijanianAlphabetProcessor azerbaijanianAlphabeteProcessor = new AzerbaijanianAlphabetProcessor();

        String actual = azerbaijanianAlphabeteProcessor.toUpperCase("məhsulun tətbiq edilib üzə gətirilməsi.");
        String expected = "MƏHSULUN TƏTBİQ EDİLİB ÜZƏ GƏTİRİLMƏSİ.";

        System.out.println(actual);

        Assert.assertEquals(expected,actual);
    }
}