Feature/bael 338 introduction dropwizard (#8572)

* [ BAEL-3388 ] : Introduction Dropwizard

* BAEL-3388: Fix formatting

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/IntroductionApplication.java

@@ -0,0 +1,51 @@
+package com.baeldung.dropwizard.introduction;
+
+import com.baeldung.dropwizard.introduction.configuration.ApplicationHealthCheck;
+import com.baeldung.dropwizard.introduction.configuration.BasicConfiguration;
+import com.baeldung.dropwizard.introduction.domain.Brand;
+import com.baeldung.dropwizard.introduction.repository.BrandRepository;
+import com.baeldung.dropwizard.introduction.resource.BrandResource;
+import io.dropwizard.Application;
+import io.dropwizard.configuration.ResourceConfigurationSourceProvider;
+import io.dropwizard.setup.Bootstrap;
+import io.dropwizard.setup.Environment;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class IntroductionApplication extends Application<BasicConfiguration> {
+
+    public static void main(final String[] args) throws Exception {
+        new IntroductionApplication().run("server", "introduction-config.yml");
+    }
+
+    @Override
+    public void run(final BasicConfiguration basicConfiguration, final Environment environment) {
+        final int defaultSize = basicConfiguration.getDefaultSize();
+        final BrandRepository brandRepository = new BrandRepository(initBrands());
+        final BrandResource brandResource = new BrandResource(defaultSize, brandRepository);
+        environment
+          .jersey()
+          .register(brandResource);
+
+        final ApplicationHealthCheck healthCheck = new ApplicationHealthCheck();
+        environment
+          .healthChecks()
+          .register("application", healthCheck);
+    }
+
+    @Override
+    public void initialize(final Bootstrap<BasicConfiguration> bootstrap) {
+        bootstrap.setConfigurationSourceProvider(new ResourceConfigurationSourceProvider());
+        super.initialize(bootstrap);
+    }
+
+    private List<Brand> initBrands() {
+        final List<Brand> brands = new ArrayList<>();
+        brands.add(new Brand(1L, "Brand1"));
+        brands.add(new Brand(2L, "Brand2"));
+        brands.add(new Brand(3L, "Brand3"));
+
+        return brands;
+    }
+}

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/configuration/ApplicationHealthCheck.java

@@ -0,0 +1,10 @@
+package com.baeldung.dropwizard.introduction.configuration;
+
+import com.codahale.metrics.health.HealthCheck;
+
+public class ApplicationHealthCheck extends HealthCheck {
+    @Override
+    protected Result check() throws Exception {
+        return Result.healthy();
+    }
+}

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/configuration/BasicConfiguration.java

@@ -0,0 +1,20 @@
+package com.baeldung.dropwizard.introduction.configuration;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import io.dropwizard.Configuration;
+
+import javax.validation.constraints.NotNull;
+
+public class BasicConfiguration extends Configuration {
+    @NotNull private final int defaultSize;
+
+    @JsonCreator
+    public BasicConfiguration(@JsonProperty("defaultSize") final int defaultSize) {
+        this.defaultSize = defaultSize;
+    }
+
+    public int getDefaultSize() {
+        return defaultSize;
+    }
+}

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/domain/Brand.java

@@ -0,0 +1,19 @@
+package com.baeldung.dropwizard.introduction.domain;
+
+public class Brand {
+    private final Long id;
+    private final String name;
+
+    public Brand(final Long id, final String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+}

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/repository/BrandRepository.java

@@ -0,0 +1,32 @@
+package com.baeldung.dropwizard.introduction.repository;
+
+import com.baeldung.dropwizard.introduction.domain.Brand;
+import com.google.common.collect.ImmutableList;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+public class BrandRepository {
+    private final List<Brand> brands;
+
+    public BrandRepository(final List<Brand> brands) {
+        this.brands = ImmutableList.copyOf(brands);
+    }
+
+    public List<Brand> findAll(final int size) {
+        return brands
+          .stream()
+          .limit(size)
+          .collect(Collectors.toList());
+    }
+
+    public Optional<Brand> findById(final Long id) {
+        return brands
+          .stream()
+          .filter(brand -> brand
+            .getId()
+            .equals(id))
+          .findFirst();
+    }
+}

dropwizard/src/main/java/com/baeldung/dropwizard/introduction/resource/BrandResource.java

@@ -0,0 +1,35 @@
+package com.baeldung.dropwizard.introduction.resource;
+
+import com.baeldung.dropwizard.introduction.domain.Brand;
+import com.baeldung.dropwizard.introduction.repository.BrandRepository;
+
+import javax.ws.rs.*;
+import javax.ws.rs.core.MediaType;
+import java.util.List;
+import java.util.Optional;
+
+@Path("/brands")
+@Produces(MediaType.APPLICATION_JSON)
+public class BrandResource {
+    private final int defaultSize;
+    private final BrandRepository brandRepository;
+
+    public BrandResource(final int defaultSize, final BrandRepository brandRepository) {
+        this.defaultSize = defaultSize;
+        this.brandRepository = brandRepository;
+
+    }
+
+    @GET
+    public List<Brand> getBrands(@QueryParam("size") final Optional<Integer> size) {
+        return brandRepository.findAll(size.orElse(defaultSize));
+    }
+
+    @GET
+    @Path("/{id}")
+    public Brand getById(@PathParam("id") final Long id) {
+        return brandRepository
+          .findById(id)
+          .orElseThrow(RuntimeException::new);
+    }
+}

dropwizard/src/main/resources/introduction-config.yml

@@ -0,0 +1 @@
+defaultSize: 5