solved task

src/main/java/core/mate/academy/model/Bulldozer.java

@@ -1,9 +1,5 @@
 package core.mate.academy.model;
 
-/**
- * Add some custom fields that could be only in Bulldozer
- * Do not remove no-args constructor
- */
 public class Bulldozer extends Machine {
  public Bulldozer() {
  }

src/main/java/core/mate/academy/model/Excavator.java

@@ -1,9 +1,5 @@
 package core.mate.academy.model;
 
-/**
- * Add some custom fields that could be only in Excavator
- * Do not remove no-args constructor
- */
 public class Excavator extends Machine {
  public Excavator() {
  }

src/main/java/core/mate/academy/model/Truck.java

@@ -1,9 +1,5 @@
 package core.mate.academy.model;
 
-/**
- * Add some custom fields that could be only in Truck
- * Do not remove no-field constructor
- */
 public class Truck extends Machine {
  public Truck() {
  }

src/main/java/core/mate/academy/service/BulldozerProducer.java

@@ -0,0 +1,16 @@
+package core.mate.academy.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import core.mate.academy.model.Bulldozer;
+
+public class BulldozerProducer implements MachineProducer<Bulldozer> {
+ @Override
+ public List<Bulldozer> get() {
+ List<Bulldozer> bulldozers = new ArrayList<>();
+ bulldozers.add(new Bulldozer());
+ bulldozers.add(new Bulldozer());
+ return bulldozers;
+ }
+}

src/main/java/core/mate/academy/service/ExcavatorProducer.java

@@ -0,0 +1,16 @@
+package core.mate.academy.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import core.mate.academy.model.Excavator;
+
+public class ExcavatorProducer implements MachineProducer<Excavator> {
+ @Override
+ public List<Excavator> get() {
+ List<Excavator> excavators = new ArrayList<>();
+ excavators.add(new Excavator());
+ excavators.add(new Excavator());
+ return excavators;
+ }
+}

src/main/java/core/mate/academy/service/MachineProducer.java

@@ -1,11 +1,9 @@
 package core.mate.academy.service;
 
+import core.mate.academy.model.Machine;
+
 import java.util.List;
 
-public interface MachineProducer {
- /**
- * In your implementations - create 2-3 models, add them to the list and return
- * @return - the list of models
- */
- List<Object> get();
+public interface MachineProducer<T extends Machine> {
+ List<T> get();
 }

src/main/java/core/mate/academy/service/MachineService.java

@@ -1,38 +1,13 @@
 package core.mate.academy.service;
 
-import java.util.List;
+import core.mate.academy.model.Machine;
 
-/**
- * Parameterize this service and add its implementation in a separate class.
- */
-public interface MachineService {
+import java.util.List;
 
- /**
- * Return the list of machines.
- * In the implementation of this method please use your MachineProducer implementations
- * See that 'Class type' is not parametrized.
- * Consider to parametrize this Class< PARAMETRIZE_ME > with specific wildcard bounding
- *
- * @param type - any class of Machine sub class. For example: Truck.class or Bulldozer.class
- * @return the list of machines
- */
- List<Object> getAll(Class type);
+public interface MachineService<T extends Machine> {
+ List<T> getAll(Class<? extends T> type);
 
- /**
- * Fill the machines list with passed value
- * Replace the Object with parametrized value.
- * This method should be able to work well with any type of machine passed as 'value'
- *
- * @param machines - list of machines to be filled with value
- * @param value - any object of machine sub class
- */
- void fill(List<Object> machines, Object value);
+ void fill(List<? super T> machines, T value);
 
- /**
- * Call the method doWork() from each machine.
- * This method should be able to accept a list of bulldozers as well as list of trucks.
- *
- * @param machines - the list of machines
- */
- void startWorking(List<Object> machines);
+ void startWorking(List<? extends T> machines);
 }

src/main/java/core/mate/academy/service/MachineServiceImpl.java

@@ -1,7 +1,37 @@
 package core.mate.academy.service;
 
-/**
- * Your implementation of MachineService.
- */
-public class MachineServiceImpl {
+import core.mate.academy.model.Bulldozer;
+import core.mate.academy.model.Excavator;
+import core.mate.academy.model.Machine;
+import core.mate.academy.model.Truck;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class MachineServiceImpl<T extends Machine> implements MachineService<T> {
+ @Override
+ public List<T> getAll(Class<? extends T> type) {
+ if (type == Bulldozer.class) {
+ return (List<T>) new BulldozerProducer().get();
+ } else if (type == Excavator.class) {
+ return (List<T>) new ExcavatorProducer().get();
+ } else if (type == Truck.class) {
+ return (List<T>) new TruckProducer().get();
+ }
+ return new ArrayList<>();
+ }
+
+ @Override
+ public void fill(List<? super T> machines, T value) {
+ for (int i = 0; i < machines.size(); i++) {
+ machines.set(i, value);
+ }
+ }
+
+ @Override
+ public void startWorking(List<? extends T> machines) {
+ for (T machine : machines) {
+ machine.doWork();
+ }
+ }
 }

src/main/java/core/mate/academy/service/TruckProducer.java

@@ -0,0 +1,16 @@
+package core.mate.academy.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import core.mate.academy.model.Truck;
+
+public class TruckProducer implements MachineProducer<Truck> {
+ @Override
+ public List<Truck> get() {
+ List<Truck> trucks = new ArrayList<>();
+ trucks.add(new Truck());
+ trucks.add(new Truck());
+ return trucks;
+ }
+}