android_case.md

1. Sharepreferences

Sharepreferences supports getAll() , while fastkv supports putAll(), so it is convenient to import Sharepreferences data to FastKV.

public class CommonStore {
    public static final String NAME = "common_store";
    // original case
    // public static final SharedPreferences preferences = GlobalConfig.appContext.getSharedPreferences(NAME, Context.MODE_PRIVATE);

    // import SharedPreferences's data
    public static final SharedPreferences preferences = FastPreferences.adapt(GlobalConfig.appContext, NAME, false);
}

The implementation of FastPreferences like this：

public class FastPreferences implements SharedPreferences {
    private static final String IMPORT_FLAG = "import_flag";

    protected final FastKV kv;
    protected final FastEditor editor = new FastEditor();

    public FastPreferences(String path, String name) {
        kv = new FastKV.Builder(path, name).build();
    }

    public static SharedPreferences adapt(Context context, String name, boolean deleteOldData) {
        String path = context.getFilesDir().getAbsolutePath() + "/fastkv";
        FastPreferences newPreferences = new FastPreferences(path, name);
        if (!newPreferences.contains(IMPORT_FLAG)) {
            SharedPreferences oldPreferences = context.getSharedPreferences(name, Context.MODE_PRIVATE);
            //noinspection unchecked
            Map<String, Object> allData = (Map<String, Object>) oldPreferences.getAll();
            FastKV kv = newPreferences.getKV();
            kv.putAll(allData);
            kv.putBoolean(IMPORT_FLAG, true);
            if (deleteOldData) {
                oldPreferences.edit().clear().apply();
            }
        }
        return newPreferences;
    }
    
    private class FastEditor implements SharedPreferences.Editor {
        @Override
        public Editor putString(String key, @Nullable String value) {
            kv.putString(key, value);
            return this;
        }
    }
    // ...
}

FastPreferences is the implementation class of SharedPreferences, which uses FastKV to store key-values. Replacing the SDK's SharedPreferencesImpl with FastPreferences, no need to change other codes because FastPreferences has the same API with SharedPreferencesImpl.

2. Kotlin

Kotlin is compatible with java, so you could directly use FastKV or SharedPreferences APIs in Kotlin. In addition, kotlin provides the syntax of delegate, which can be used to improve key-value API's accessing.

For example：

Define：

object UserData: KVData("user_data") {
    override fun encoders(): Array<FastKV.Encoder<*>> {
        return arrayOf(AccountInfo.ENCODER, LongListEncoder)
    }

    var userAccount by obj("user_account", AccountInfo.ENCODER)
    var isVip by boolean("is_vip")
    var fansCount by int("fans_count")
    var score by float("score")
    var loginTime by long("login_time")
    var balance by double("balance")
    var sign by string("sing")
    var lock by array("lock")
    var tags by stringSet("tags")
    var favoriteChannels by obj("favorite_channels", LongListEncoder)
}

Access：

fun login(uid: Long) {
    val account = AccountInfo(uid, "mock token", "hello", "12312345678", "foo@gmail.com")
    UserData.userAccount = account
    fetchUserInfo()
}

fun fetchUserInfo() {
    UserData.run {
        isVip = true
        fansCount = 99
        score = 4.5f
        loginTime = System.currentTimeMillis()
        balance = 99999.99
        sign = "The journey of a thousand miles begins with a single step."
        lock = Utils.md5("12347".toByteArray())
        tags = setOf("travel", "foods", "cats")
        favoriteChannels = listOf(1234567, 1234568, 2134569)
    }
}

The KVData class implement like this：

open class KVData(name: String) {
    val kv: FastKV by lazy {
        FastKV.Builder(PathManager.fastKVDir, name).encoder(encoders()).build()
    }

    protected open fun encoders(): Array<FastKV.Encoder<*>>? {
        return null
    }

    protected fun boolean(key: String, defValue: Boolean = false) = BooleanProperty(key, defValue)
    protected fun int(key: String, defValue: Int = 0) = IntProperty(key, defValue)
    protected fun float(key: String, defValue: Float = 0f) = FloatProperty(key, defValue)
    protected fun long(key: String, defValue: Long = 0L) = LongProperty(key, defValue)
    protected fun double(key: String, defValue: Double = 0.0) = DoubleProperty(key, defValue)
    protected fun string(key: String, defValue: String = "") = StringProperty(key, defValue)
    protected fun array(key: String, defValue: ByteArray = EMPTY_ARRAY) = ArrayProperty(key, defValue)
    protected fun stringSet(key: String, defValue: Set<String>? = null) = StringSetProperty(key, defValue)
    protected fun <T> obj(key: String, encoder: FastKV.Encoder<T>) = ObjectProperty(key, encoder)

    companion object {
        val EMPTY_ARRAY = ByteArray(0)
    }
}

class BooleanProperty(private val key: String, private val defValue: Boolean) :
    ReadWriteProperty<KVData, Boolean> {
    override fun getValue(thisRef: KVData, property: KProperty<*>): Boolean {
        return thisRef.kv.getBoolean(key, defValue)
    }

    override fun setValue(thisRef: KVData, property: KProperty<*>, value: Boolean) {
        thisRef.kv.putBoolean(key, value)
    }
}
// ...