import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * {@link <a href=
 * "https://[Log in to view URL]"
 * target= "_blank"></a>}
 * 
 * @author itammb ( Italia Massimiliano Buscati )
 * @version JDK 1.15
 *
 */
class Main {
	private static class Product {
		private int id;
		private String name;
		private float price;

		@Override
		public String toString() {
			return "Product [id=" + id + ", name=" + name + ", price=" + price + "]";
		}

		private Product(int id, String name, float price) {
			this.id = id;
			this.name = name;
			this.price = price;
		}
	}

	private static class UniTest {
		/**
		 * @see Stream#filter(java.util.function.Predicate)
		 * @see Stream#forEach(java.util.function.Consumer)
		 *
		 */
		public void operation_stateless_filter(List<Product> source) {
			Stream<Product> productS = source.stream().filter(product -> product.price > 30000); // <- operazioni
																									// intermedie
			productS.forEach(product -> System.out.println(product)); // <- operazioni terminale
		}

		/**
		 * @see Stream#map(java.util.function.Function)
		 * @see Stream#forEach(java.util.function.Consumer)
		 *
		 */
		public void operation_stateless_map(List<Product> source) {
			Stream<Float> prizeS = source.stream().map(product -> product.price); // <- operazioni intermedie
			prizeS.forEach(prize -> System.out.println(prize)); // <- operazioni terminale
		}

		/**
		 * @see Stream#map(java.util.function.Function)
		 * @see Stream#collect(java.util.stream.Collector)
		 * @see Collectors#toList()
		 *
		 */
		public void operation_stateless_collect(List<Product> source) {
			List<Float> rPrize = source.stream().map(product -> product.price).collect(Collectors.toList()); // <-
																												// operazioni
																												// terminale-raccolta
			System.out.println(rPrize);
		}

		public void operation_stateless_many_operations(List<Product> source) {
			List<Float> rPrize = source.stream().filter(product -> product.price > 30000).map(product -> product.price)
					.collect(Collectors.toList());
			System.out.println(rPrize);
		}
		
		public void operation_stateless_navigation(List<Product> source) {
			source.stream().filter( product -> product.price == 30000 ).forEach( product -> System.out.println( product ) ); 
		}
	    
		public static List<Product> createTest() {
			// elementi in serie
			return new ArrayList<Product>() {
				private static final long serialVersionUID = -69L;

				{
					add(new Product(1, "HP Laptop", 25000f));
					add(new Product(2, "Dell Laptop", 30000f));
					add(new Product(3, "Lenevo Laptop", 28000f));
					add(new Product(4, "Sony Laptop", 28000f));
					add(new Product(5, "Apple Laptop", 90000f));
				}
			};
		}
	}

	public static void main(String args[]) {
		// Unit test - sorgente input -> pipeline :: filtro -> nuovo flusso
		new UniTest().operation_stateless_filter(UniTest.createTest());

		// Unit test - sorgente input -> pipeline :: estrazione elemento -> nuovo flusso
		new UniTest().operation_stateless_map(UniTest.createTest());

		// Unit test - sorgente input -> pipeline :: raccolta elemeno -> nuova sorgente
		// elaborazione in un unico passaggio
		new UniTest().operation_stateless_collect(UniTest.createTest());

		// Unit test - sorgente input -> pipeline :: composizione di più operazioni
		// stateless -> nuova sorgente
		new UniTest().operation_stateless_many_operations(UniTest.createTest());
		
		// Unit test - navigazione -> nuovo flusso
		new UniTest().operation_stateless_navigation(UniTest.createTest());
	}
}