Lecture 6 & Lecture 11

src/main/java/com/rxmobileteam/lecture1/Exercise1Main.java

@@ -1,12 +1,14 @@
 package com.rxmobileteam.lecture1;
 
+import com.rxmobileteam.lecture1.data.ProductDao;
 import com.rxmobileteam.lecture1.factory.ProductServiceFactory;
 import com.rxmobileteam.lecture1.service.Product;
 import com.rxmobileteam.lecture1.service.ProductService;
 
 public class Exercise1Main {
     public static void main(String[] args) {
-        ProductService productService = new ProductServiceFactory().createProductService();
+        ProductDao dao = new ProductDao();
+        ProductService productService = new ProductServiceFactory().createProductService(dao);
 
         Product iPhone12 = new Product(
             "1",

src/main/java/com/rxmobileteam/lecture1/data/IDao.java

@@ -0,0 +1,14 @@
+package com.rxmobileteam.lecture1.data;
+
+import com.rxmobileteam.lecture1.service.Product;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+import java.util.Set;
+
+public interface IDao {
+    boolean add(@NotNull Product product);
+    @NotNull Set<Product> findAll();
+    @NotNull List<Product> findByQuery(String query);
+}

src/main/java/com/rxmobileteam/lecture1/data/ProductDao.java

@@ -2,9 +2,11 @@
 
 import com.rxmobileteam.lecture1.service.Product;
 import com.rxmobileteam.utils.ExerciseNotCompletedException;
+
 import org.jetbrains.annotations.NotNull;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 /**
@@ -14,7 +16,7 @@
  * todo: 1. Implement a method {@link ProductDao#add(Product)} that store new product into the set
  * todo: 2. Implement a method {@link ProductDao#findAll()} that returns a set of all products
  */
-public class ProductDao {
+public class ProductDao implements IDao {
     private final Set<Product> products = new HashSet<>();
 
     /**
@@ -24,8 +26,7 @@ public class ProductDao {
      * @return {@code true} if a product was stored, {@code false} otherwise
      */
     public boolean add(@NotNull Product product) {
-        // TODO: implement this method
-        throw new ExerciseNotCompletedException();
+        return products.add(product);
     }
 
     /**
@@ -35,8 +36,16 @@ public boolean add(@NotNull Product product) {
      */
     @NotNull
     public Set<Product> findAll() {
-        // TODO: implement this method
-        throw new ExerciseNotCompletedException();
+        return products;
+    }
+
+    @Override
+    public @NotNull List<Product> findByQuery(String query) {
+        return products.stream().filter(product ->
+            product.getName().toLowerCase().contains(
+                query.toLowerCase()) ||
+                product.getDescription().toLowerCase().contains(query.toLowerCase())
+        ).toList();
     }
 
 }

src/main/java/com/rxmobileteam/lecture1/factory/ProductServiceFactory.java

@@ -1,7 +1,9 @@
 package com.rxmobileteam.lecture1.factory;
 
+import com.rxmobileteam.lecture1.data.IDao;
 import com.rxmobileteam.lecture1.service.ProductService;
 import com.rxmobileteam.utils.ExerciseNotCompletedException;
+
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -17,8 +19,7 @@ public class ProductServiceFactory {
      * @return ProductService
      */
     @NotNull
-    public ProductService createProductService() {
-        // TODO: implement this method
-        throw new ExerciseNotCompletedException();
+    public ProductService createProductService(IDao dao) {
+        return new ProductService(dao);
     }
 }

src/main/java/com/rxmobileteam/lecture1/service/Product.java

@@ -55,4 +55,12 @@ public String toString() {
             ", price=" + price +
             '}';
     }
+
+    public @NotNull String getName() {
+        return name;
+    }
+
+    public @NotNull String getDescription() {
+        return description;
+    }
 }

src/main/java/com/rxmobileteam/lecture1/service/ProductService.java

@@ -1,7 +1,9 @@
 package com.rxmobileteam.lecture1.service;
 
+import com.rxmobileteam.lecture1.data.IDao;
 import com.rxmobileteam.lecture1.data.ProductDao;
 import com.rxmobileteam.utils.ExerciseNotCompletedException;
+
 import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
@@ -13,6 +15,11 @@
  * TODO: 2. Using {@link ProductDao} implement method {@link ProductService#searchProducts(String)}
  */
 public class ProductService {
+    private final IDao dao;
+
+    public ProductService(IDao dao) {
+        this.dao = dao;
+    }
 
     /**
      * Adds a new product to the system.
@@ -21,8 +28,7 @@ public class ProductService {
      * @return {@code true} if a product was added, {@code false} otherwise.
      */
     public boolean addProduct(@NotNull Product product) {
-        // TODO: implement this method
-        throw new ExerciseNotCompletedException();
+        return dao.add(product);
     }
 
     /**
@@ -33,7 +39,7 @@ public boolean addProduct(@NotNull Product product) {
      */
     @NotNull
     public List<Product> searchProducts(@NotNull String query) {
-        // TODO: implement this method
-        throw new ExerciseNotCompletedException();
+        List<Product> list = dao.findByQuery(query);
+        return dao.findByQuery(query);
     }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle1.kt

@@ -11,7 +11,7 @@ object Riddle1 {
    */
   fun solve(value: Int): Observable<Int> {
     // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return Observable.just(value)
   }
 }
 

src/main/java/com/rxmobileteam/lecture11/Riddle10.kt

@@ -9,8 +9,13 @@ object Riddle10 {
    *
    * Use case: Get some user data and perform a network request with the user data and have both data accessible afterwards.
    */
-  fun solve(first: Observable<Int>, function: (Int) -> Observable<String>): Observable<Pair<Int, String>> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+  fun solve(
+    first: Observable<Int>,
+    function: (Int) -> Observable<String>
+  ): Observable<Pair<Int, String>> {
+    return first.flatMap(
+      { value -> function(value) },
+      { value: Int, functionResult: String -> Pair(value, functionResult) }
+    )
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle11.kt

@@ -2,6 +2,7 @@ package com.rxmobileteam.lecture11
 
 import com.rxmobileteam.utils.ExerciseNotCompletedException
 import io.reactivex.rxjava3.core.Observable
+import java.util.concurrent.TimeUnit
 
 object Riddle11 {
   /**
@@ -10,7 +11,6 @@ object Riddle11 {
    * Use case: Handle the click of a button right away but prevent double clicking by not handling multiple click events within a given time window.
    */
   fun solve(source: Observable<Unit>): Observable<Unit> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.throttleFirst(300L, TimeUnit.MILLISECONDS)
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle12.kt

@@ -10,7 +10,6 @@ object Riddle12 {
    * Use case: Getting a network error and you want to recover and show some default state.
    */
   fun solve(source: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.onErrorReturnItem(5)
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle13.kt

@@ -10,7 +10,6 @@ object Riddle13 {
    * Use case: You only want to observe changes of a value but don't care if the same value has been emitted consecutively.
    */
   fun solve(source: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.distinctUntilChanged()
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle14.kt

@@ -10,7 +10,6 @@ object Riddle14 {
    * Use case: Retry an operation for a number of times or until a valid error occurred.
    */
   fun solve(source: Single<Unit>): Single<Unit> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.retry(2) { t -> t !is IllegalArgumentException }
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle15.kt

@@ -10,7 +10,6 @@ object Riddle15 {
    * Use case: You have two sources of your data (cache & network request). You want to subscribe to both right away and keep the emission order.
    */
   fun solve(first: Observable<Int>, second: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return Observable.concatEager(listOf(first, second))
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle16.kt

@@ -12,7 +12,8 @@ object Riddle16 {
    * Use case: The [source] Observable is a TextField and you want to issue a network request while disposing the old requests in case the user has typed something new.
    */
   fun solve(source: Observable<String>, function: (String) -> Single<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.switchMapSingle {
+      function(it)
+    }
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle17.kt

@@ -10,7 +10,6 @@ object Riddle17 {
    * Use case: Reactive types are lazy by default. Hence, you might also want to get the value upon the subscription and not execution time.
    */
   fun solve(function: () -> Int): Single<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return Single.fromSupplier(function)
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle18.kt

@@ -10,7 +10,6 @@ object Riddle18 {
    * Use case: You have multiple sources and want to get the data from either one and then be consistent and not switch between multiple sources.
    */
   fun solve(first: Observable<Int>, second: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return Observable.amb(listOf(first, second))
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle19.kt

@@ -11,8 +11,9 @@ object Riddle19 {
    * Use case: Transform any listener into an Observable.
    */
   fun solve(interaction: Interaction): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return Observable.create { emitter ->
+      interaction.listener = emitter::onNext
+    }
   }
 
   interface Interaction {

src/main/java/com/rxmobileteam/lecture11/Riddle2.kt

@@ -10,7 +10,6 @@ object Riddle2 {
    * Use case: You want to transform the data.
    */
   fun solve(source: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.map { it + 1 }
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle20.kt

@@ -10,7 +10,6 @@ object Riddle20 {
    * Use case: There something you want to execute and in your UI you have multiple trigger points.
    */
   fun solve(first: Observable<Int>, second: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return first.mergeWith(second)
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle21.kt

@@ -10,7 +10,6 @@ object Riddle21 {
    * Use case: Sometimes you can't do everything reactively and need to break out of it.
    */
   fun solve(source: Observable<Int>): Int {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.blockingFirst()
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle22.kt

@@ -10,7 +10,6 @@ object Riddle22 {
    * Use case: Group related data while skipping over some of it.
    */
   fun solve(source: Observable<Int>): Observable<List<Int>> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.buffer(2, 3)
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle23.kt

@@ -10,7 +10,6 @@ object Riddle23 {
    * Use case: You get some data from a bad source and know for sure it's of a certain type that you require.
    */
   fun solve(source: Observable<Any>): Observable<String> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.map { it as String }
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle24.kt

@@ -11,7 +11,6 @@ object Riddle24 {
    * Use case: Know how many emissions have been sent out.
    */
   fun solve(source: Observable<Any>): Single<Long> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.count()
   }
 }

src/main/java/com/rxmobileteam/lecture11/Riddle25.kt

@@ -10,7 +10,6 @@ object Riddle25 {
    * Use case: Continue with data if the stream is empty.
    */
   fun solve(source: Observable<Int>): Observable<Int> {
-    // TODO: implement this method
-    throw ExerciseNotCompletedException()
+    return source.defaultIfEmpty(5)
   }
 }