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Jv dependency injection solution #699

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2 changes: 1 addition & 1 deletion pom.xml
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@


<properties>
<jdk.version>11</jdk.version>
<jdk.version>17</jdk.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven.checkstyle.plugin.version>3.1.1</maven.checkstyle.plugin.version>
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2 changes: 1 addition & 1 deletion src/main/java/mate.academy/Main.java
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ public class Main {
public static void main(String[] args) {
// Please test your Injector here. Feel free to push this class as a part of your solution
Injector injector = Injector.getInjector();
ProductService productService = null;
ProductService productService = (ProductService) injector.getInstance(ProductService.class);
List<Product> products = productService.getAllFromFile("products.txt");
products.forEach(System.out::println);
}
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8 changes: 7 additions & 1 deletion src/main/java/mate.academy/lib/Component.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,11 @@
package mate.academy.lib;

public @interface Component {
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Component {
}
8 changes: 7 additions & 1 deletion src/main/java/mate.academy/lib/Inject.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,11 @@
package mate.academy.lib;

public @interface Inject {
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Inject {
}
76 changes: 73 additions & 3 deletions src/main/java/mate.academy/lib/Injector.java
Original file line number Diff line number Diff line change
@@ -1,13 +1,83 @@
package mate.academy.lib;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
import mate.academy.service.FileReaderService;
import mate.academy.service.ProductParser;
import mate.academy.service.ProductService;
import mate.academy.service.impl.FileReaderServiceImpl;
import mate.academy.service.impl.ProductParserImpl;
import mate.academy.service.impl.ProductServiceImpl;

public class Injector {
private static final Injector injector = new Injector();
private static final Injector INJECTOR = new Injector();
private static final Map<Class<?>, Class<?>> INTERFACES_IMPLEMENTATIONS = Map.of(
FileReaderService.class, FileReaderServiceImpl.class,
ProductParser.class, ProductParserImpl.class,
ProductService.class, ProductServiceImpl.class);
private static final Map<Class<?>, Object> INSTANCES = new HashMap<>();

public static Injector getInjector() {
return injector;
return INJECTOR;
}

public Object getInstance(Class<?> interfaceClazz) {
return null;
Object clazzImplementationInstance = null;
Class<?> clazz = findImplementation(interfaceClazz);
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(Inject.class)) {
Object fieldInstance = getInstance(field.getType());
clazzImplementationInstance = createNewInstance(clazz);
field.setAccessible(true);
try {
field.set(clazzImplementationInstance, fieldInstance);
} catch (IllegalAccessException e) {
throw new RuntimeException("Can't initialize field value. Class: "
+ clazz.getName() + ", field: " + field.getName());
}
}
}
return clazzImplementationInstance == null ? createNewInstance(clazz)
: clazzImplementationInstance;
}

private Object createNewInstance(Class<?> clazz) {
if (INSTANCES.containsKey(clazz)) {
return INSTANCES.get(clazz);
}
try {
Constructor<?> constructor = clazz.getConstructor();
Object instance = constructor.newInstance();
INSTANCES.put(clazz, instance);
return instance;
} catch (ReflectiveOperationException e) {
throw new RuntimeException("Can't create new instance of class - " + clazz.getName());
}
}

private Class<?> findImplementation(Class<?> interfaceClazz) {
if (interfaceClazz.isInterface()) {
interfaceCheck(interfaceClazz);
interfaceClazz = INTERFACES_IMPLEMENTATIONS.get(interfaceClazz);
}
componentCheck(interfaceClazz);
return interfaceClazz;
}

private void componentCheck(Class<?> clazz) {
if (!clazz.isAnnotationPresent(Component.class)) {
throw new RuntimeException("Unsupported class - " + clazz
+ ", should be annotated by @Component");
}
}

private void interfaceCheck(Class<?> clazz) {
if (!INTERFACES_IMPLEMENTATIONS.containsKey(clazz)) {
throw new RuntimeException("Unsupported interface - " + clazz.getName());
}
}
}

Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,10 @@
import java.io.IOException;
import java.nio.file.Files;
import java.util.List;
import mate.academy.lib.Component;
import mate.academy.service.FileReaderService;

@Component
public class FileReaderServiceImpl implements FileReaderService {
@Override
public List<String> readFile(String fileName) {
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Original file line number Diff line number Diff line change
@@ -1,9 +1,11 @@
package mate.academy.service.impl;

import java.math.BigDecimal;
import mate.academy.lib.Component;
import mate.academy.model.Product;
import mate.academy.service.ProductParser;

@Component
public class ProductParserImpl implements ProductParser {
public static final int ID_POSITION = 0;
public static final int NAME_POSITION = 1;
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Original file line number Diff line number Diff line change
Expand Up @@ -2,13 +2,18 @@

import java.util.List;
import java.util.stream.Collectors;
import mate.academy.lib.Component;
import mate.academy.lib.Inject;
import mate.academy.model.Product;
import mate.academy.service.FileReaderService;
import mate.academy.service.ProductParser;
import mate.academy.service.ProductService;

@Component
public class ProductServiceImpl implements ProductService {
@Inject
private ProductParser productParser;
@Inject
private FileReaderService fileReaderService;

@Override
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