FrancescoJo

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE resources [
  <!ENTITY appname "WhereDat">
  <!ENTITY author "Oded">
]>

<resources>
    <string name="app_name">&appname;</string>
    <string name="description">The &appname; app was created by &author;</string>
</resources>

FrancescoJo

String path = "android.resource://" + context.getPackageName() + "/" + R.raw.raw_resource_id;
Uri rawUri  = Uri.parse(path);

FrancescoJo

import java.util.regex.Matcher
import java.util.regex.Pattern

// ext makes method callable project wide
ext.getCurrentFlavor = { ->
    Gradle gradle = getGradle()
    String tskReqStr = gradle.getStartParameter().getTaskRequests().toString()

    Pattern pattern;

FrancescoJo

use -assumenosideeffects

https://www.guardsquare.com/en/proguard/manual/usage
http://qiita.com/gfx/items/e412dab7f127b7ae44d8
https://github.com/gfx/ProguardRemovesObjectWait

FrancescoJo

class EvenOddPickGame(private val randomIntGen : RandomValueGenerator<Integer>) {
    fun pick(times: Int): List<String> {
        return ArrayList<String>().apply {
            for (i in 0 until times) {
                val rolled = randomIntGen.nextRandom(lowerBound = 1, upperBound = 2) % 2
                if (rolled == 0) {
                    add("EVEN")
                } else {
                    add("ODD")
                }

FrancescoJo

/**
 * This logic demonstrates how to draw all nCr combinations from given set.
 * The time complexity of this logic is O(n²).
 * Actual logic invocations are 1/2((n - 2)² + r(n - 2) + 2), where n > 2.
 *
 * Imagine selecting 3 different numbers from a set which has 4 different 
 * numbers. Assume that we've given a set as follows:
 * 
 * let dataSet = {1, 2, 3, 4}
 * 

FrancescoJo

interface EnumWithKey<T, K> {
    val T.key: K
}

/*
 * The reified type parameter lets you call the function without explicitly 
 * passing the Class-object.
 */
inline fun <reified T : Enum<T>, R> EnumWithKey<T, R>.byKey(key: R): T? {
    return enumValues<T>().find { it.key == key }

FrancescoJo

interface UserRepository : JpaRepository<User, Long>, UserRepositoryExtension

interface UserRepositoryExtension {
  /*
   * Here we get exception as following:
   *
   * Caused by: java.lang.IllegalArgumentException: Failed to create query for method 
   *   public abstract User UserRepositoryExtension.getByRoleCriteria(java.lang.String,java.util.Set)!
   *     At least 2 parameter(s) provided but only 1 parameter(s) present in query.
   *

FrancescoJo

class Animal { }

class Reptile extends Animal { }
class Bird extends Animal { }

interface MobileLife {
  // Every classes derived from this interface should implement common features on it.
  void move(double displacement);

  double getDistance();

FrancescoJo

class Animal { }

class Reptile extends Animal { }
class Bird extends Animal { }

mixin MobileLife {
  // We don't need to implement _move on every classes using this mixin, since mixin can include state.
  var _distance = 0.0;
  
  void _move(double displacement) {