Key-Value store interface and shared preferences implementation example plus memory (mock) implemetnation

KeyStoreDataSource.java

public interface KeyStoreDataSource {

    String getString(String key, String defaultValue);
    void putString(String key, String value);
    int getInt(String key, int defaultValue);
    void putInt(String key, int value);
    long getLong(String key, long defaultValue);
    void putLong(String key, long value);
    float getFloat(String key, float defaultValue);
    void putFloat(String key, float value);
    boolean getBoolean(String key, boolean defaultValue);
    void putBoolean(String key, boolean value);
    void clear();
    Map<String, ?> getAll();

}

KeyStoreDataSourceImpl.java

public class KeyStoreDataSourceImpl implements KeyStoreDataSource {

    private static KeyStoreDataSourceImpl sKeyStoreDataSourceImpl;
    private String mSharedPrefsName;
    private SharedPreferences mSharedPrefs;

    public synchronized static KeyStoreDataSourceImpl getInstance(Context context){
        if (sKeyStoreDataSourceImpl == null){
            sKeyStoreDataSourceImpl = new KeyStoreDataSourceImpl(context, "sharedPreferenceName");
        }
        return sKeyStoreDataSourceImpl;
    }

    private KeyStoreDataSourceImpl(Context context, String sharedPreferencesName) {
        mSharedPrefsName = sharedPreferencesName;
        loadPreferences(context);
    }

    private void loadPreferences(Context context) {
        mSharedPrefs = context.getSharedPreferences(mSharedPrefsName, Context.MODE_PRIVATE);
    }

    @Override
    public String getString(String key, String defaultValue) {
        return mSharedPrefs.getString(key, defaultValue);
    }

    @Override
    public void putString(String key, String value) {
        SharedPreferences.Editor editor = mSharedPrefs.edit();
        editor.putString(key, value);
        editor.apply();
    }

    @Override
    public int getInt(String key, int defaultValue) {
        return mSharedPrefs.getInt(key, defaultValue);
    }

    @Override
    public void putInt(String key, int value) {
        SharedPreferences.Editor editor = mSharedPrefs.edit();
        editor.putInt(key, value);
        editor.apply();
    }

    @Override
    public long getLong(String key, long defaultValue) {
        return mSharedPrefs.getLong(key, defaultValue);
    }

    @Override
    public void putLong(String key, long value) {
        SharedPreferences.Editor editor = mSharedPrefs.edit();
        editor.putLong(key, value);
        editor.apply();
    }

    @Override
    public float getFloat(String key, float defaultValue) {
        return mSharedPrefs.getFloat(key, defaultValue);
    }

    @Override
    public void putFloat(String key, float value) {
        SharedPreferences.Editor editor = mSharedPrefs.edit();
        editor.putFloat(key, value);
        editor.apply();
    }

    @Override
    public boolean getBoolean(String key, boolean defaultValue) {
        return mSharedPrefs.getBoolean(key, defaultValue);
    }

    @Override
    public void putBoolean(String key, boolean value) {
        SharedPreferences.Editor editor = mSharedPrefs.edit();
        editor.putBoolean(key, value);
        editor.apply();
    }

    @Override
    public void clear() {
        mSharedPrefs.edit().clear().apply();
    }

    @Override
    public Map<String, ?> getAll() {
        return mSharedPrefs.getAll();
    }

}

MockKeyStore.java

public class MockKeyStore implements KeyStoreDataSource {

    private Map<String, Object> store = new LinkedHashMap<>();

    @Override
    public String getString(String key, String defaultValue) {
        Object value = store.get(key);
        if (value == null){
            return defaultValue;
        }
        return (String) value;
    }

    @Override
    public void putString(String key, String value) {
        store.put(key, value);
    }

    @Override
    public int getInt(String key, int defaultValue) {
        Object value = store.get(key);
        if (value == null){
            return defaultValue;
        }
        return (int) value;
    }

    @Override
    public void putInt(String key, int value) {
        store.put(key, value);
    }

    @Override
    public long getLong(String key, long defaultValue) {
        Object value = store.get(key);
        if (value == null){
            return defaultValue;
        }
        return (long) value;
    }

    @Override
    public void putLong(String key, long value) {
        store.put(key, value);
    }

    @Override
    public float getFloat(String key, float defaultValue) {
        Object value = store.get(key);
        if (value == null){
            return defaultValue;
        }
        return (float) value;
    }

    @Override
    public void putFloat(String key, float value) {
        store.put(key, value);
    }

    @Override
    public boolean getBoolean(String key, boolean defaultValue) {
        Object value = store.get(key);
        if (value == null){
            return defaultValue;
        }
        return (boolean) value;
    }

    @Override
    public void putBoolean(String key, boolean value) {
        store.put(key, value);
    }

    @Override
    public void clear() {
        store.clear();
    }

    @Override
    public Map<String, ?> getAll() {
        return store;
    }

}