Can configure @ExposedApplication for a package

Reading https://jersey.java.net/documentation/latest/deployment.html we found that one can
deploy an application without an Application subclass.
In this case we expect @ExposedApplication (with a servletName) to be set on a package in package-info.java.

jax-rs-linker-integration-tests/no-configuration-webapp/pom.xml

@@ -0,0 +1,72 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>fr.vidal.oss</groupId>
+        <artifactId>jax-rs-linker-integration-tests</artifactId>
+        <version>0.2-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>no-configuration-webapp</artifactId>
+    <packaging>war</packaging>
+
+    <name>JAX RS Linker: webapp without JAXRS Configuration</name>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.sonatype.plugins</groupId>
+                <artifactId>port-allocator-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.eclipse.jetty</groupId>
+                <artifactId>jetty-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <artifactId>maven-failsafe-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <artifactId>maven-source-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>jax-rs-linker</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>javax.ws.rs</groupId>
+            <artifactId>javax.ws.rs-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.glassfish.jersey.containers</groupId>
+            <artifactId>jersey-container-servlet</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>javax.servlet-api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.okhttp</groupId>
+            <artifactId>okhttp</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

jax-rs-linker-integration-tests/no-configuration-webapp/src/main/java/fr/vidal/oss/jax_rs_linker/it/BrandResource.java

@@ -0,0 +1,23 @@
+package fr.vidal.oss.jax_rs_linker.it;
+
+
+import fr.vidal.oss.jax_rs_linker.Linkers;
+import fr.vidal.oss.jax_rs_linker.api.Self;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+
+@Path("/brand")
+public class BrandResource {
+
+    @Self
+    @Path("/{id}")
+    @GET
+    public String getById(@PathParam("id") int id) {
+        return Linkers.brandResourceLinker()
+            .self()
+            .replace(BrandResourcePathParameters.ID, String.valueOf(id))
+            .value();
+    }
+}

jax-rs-linker-integration-tests/no-configuration-webapp/src/main/java/fr/vidal/oss/jax_rs_linker/it/package-info.java

@@ -0,0 +1,2 @@
+@fr.vidal.oss.jax_rs_linker.api.ExposedApplication(servletName = "javax.ws.rs.core.Application")
+package fr.vidal.oss.jax_rs_linker.it;

jax-rs-linker-integration-tests/no-configuration-webapp/src/main/webapp/WEB-INF/web.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns="http://www.w3.org/2001/XMLSchema"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         version="3.1"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
+
+    <servlet>
+        <servlet-name>javax.ws.rs.core.Application</servlet-name>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>javax.ws.rs.core.Application</servlet-name>
+        <url-pattern>/rest/*</url-pattern>
+    </servlet-mapping>
+</web-app>

jax-rs-linker-integration-tests/no-configuration-webapp/src/test/java/fr/vidal/oss/jax_rs_linker/it/BrandIT.java

@@ -0,0 +1,35 @@
+package fr.vidal.oss.jax_rs_linker.it;
+
+import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.Request;
+import com.squareup.okhttp.Response;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class BrandIT {
+
+    @Test
+    public void self_link_with_context_path_and_servlet_name() throws Exception {
+        Response response = request("brand/23");
+
+        assertThat(response.body().string())
+                .isEqualTo("/it-tests/rest/brand/23");
+    }
+
+    private static Response request(String resource) throws IOException {
+        OkHttpClient client = new OkHttpClient();
+
+        Request request = new Request.Builder()
+                .url("http://localhost:" + port() + "/it-tests/rest/" + resource)
+                .build();
+
+        return client.newCall(request).execute();
+    }
+
+    private static String port() {
+        return System.getProperty("jetty.port", "8080");
+    }
+}

jax-rs-linker-integration-tests/pom.xml

@@ -107,5 +107,6 @@
     <modules>
         <module>no-xml-webapp</module>
         <module>xml-webapp</module>
+        <module>no-configuration-webapp</module>
     </modules>
 </project>

jax-rs-linker/src/main/java/fr/vidal/oss/jax_rs_linker/LinkerAnnotationProcessor.java

@@ -26,6 +26,7 @@
 import javax.annotation.processing.*;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.Element;
+import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
 import javax.tools.JavaFileObject;
 import javax.ws.rs.ApplicationPath;
@@ -39,6 +40,7 @@
 import static com.google.common.base.Predicates.notNull;
 import static com.google.common.base.Throwables.propagate;
 import static fr.vidal.oss.jax_rs_linker.errors.CompilationError.INCONSISTENT_APPLICATION_MAPPING;
+import static fr.vidal.oss.jax_rs_linker.errors.CompilationError.NO_APPLICATION_SERVLET_NAME;
 import static fr.vidal.oss.jax_rs_linker.functions.JavaxElementToMappings.intoOptionalMapping;
 import static fr.vidal.oss.jax_rs_linker.functions.MappingToPathParameters.TO_PATH_PARAMETERS;
 import static fr.vidal.oss.jax_rs_linker.predicates.ElementHasKind.byKind;
@@ -152,15 +154,21 @@ private Optional<String> parseApplicationName(RoundEnvironment roundEnv) {
             messager.printMessage(ERROR, CompilationError.ONE_APPLICATION_ONLY.text());
             return absent();
         }
-        Element application = applications.iterator().next();
-        return applicationName((TypeElement) application);
+        return applicationName(applications.iterator().next());
     }
 
-    private Optional<String> applicationName(TypeElement application) {
-        ApplicationPath applicationPath = application.getAnnotation(ApplicationPath.class);
+    private Optional<String> applicationName(Element application) {
         String servletName = application.getAnnotation(ExposedApplication.class).servletName();
-        String applicationName = String.valueOf(application.getQualifiedName());
+        if (application instanceof PackageElement) {
+            if (servletName.isEmpty()) {
+                messager.printMessage(ERROR, NO_APPLICATION_SERVLET_NAME.format(application), application);
+                return absent();
+            }
+            return Optional.of(servletName);
+        }
 
+        ApplicationPath applicationPath = application.getAnnotation(ApplicationPath.class);
+        String applicationName = String.valueOf(((TypeElement) application).getQualifiedName());
         if (!(applicationPath != null ^ !servletName.isEmpty())) {
             messager.printMessage(ERROR, INCONSISTENT_APPLICATION_MAPPING.format(applicationName), application);
             return absent();

jax-rs-linker/src/main/java/fr/vidal/oss/jax_rs_linker/errors/CompilationError.java

@@ -36,6 +36,10 @@ public enum CompilationError {
     ),
     NO_APPLICATION_FOUND(
         "\n\tThere should be exactly one @ExposedApplication-annotated Jersey Application: none found."
+    ),
+    NO_APPLICATION_SERVLET_NAME(
+        "\n\t@ExposedApplication servletName must not be empty when used on a package." +
+        "\n\tGiven package: <%s>"
     );
 
     private final String errorMessage;

jax-rs-linker/src/test/java/fr/vidal/oss/jax_rs_linker/LinkerAnnotationProcessorTest.java

@@ -114,4 +114,35 @@ public void fails_to_compile_ambiguous_configuration_class() {
             )
             .in(configuration);
     }
+
+    @Test
+    public void generate_linkers_with_exposed_application_on_package() {
+        assert_().about(javaSources())
+            .that(ImmutableList.of(
+                forResource("package-info.java"),
+                forResource("BrandResource.java")
+            ))
+            .processedWith(processor)
+            .compilesWithoutError()
+            .and()
+            .generatesSources(
+                forResource("BrandResourceLinker.java"),
+                forResource("linkers/LinkersPackageInfo.java")
+            );
+    }
+
+    @Test
+    public void fails_to_compile_without_jaxrs_configuration_and_servletName() {
+        JavaFileObject configuration = forResource("mispackage/package-info.java");
+
+        assert_().about(javaSource())
+            .that(configuration)
+            .processedWith(processor)
+            .failsToCompile()
+            .withErrorContaining(
+                "\n  \t@ExposedApplication servletName must not be empty when used on a package." +
+                "\n  \tGiven package: <mispackage>"
+            )
+            .in(configuration);
+    }
 }

jax-rs-linker/src/test/resources/linkers/LinkersPackageInfo.java

@@ -0,0 +1,32 @@
+
+package fr.vidal.oss.jax_rs_linker;
+
+import fr.vidal.oss.jax_rs_linker.servlet.ContextPaths;
+import javax.annotation.Generated;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+import javax.servlet.annotation.WebListener;
+import fr.vidal.oss.jax_rs_linker.parser.BrandResourceLinker;
+
+@WebListener
+@Generated("fr.vidal.oss.jax_rs_linker.LinkerAnnotationProcessor")
+public class Linkers
+        implements ServletContextListener {
+
+    private static String contextPath = "";
+
+    private static String applicationName = "my-super-application";
+
+    @Override
+    public void contextInitialized(ServletContextEvent sce) {
+        contextPath = ContextPaths.contextPath(sce.getServletContext(), applicationName);
+    }
+
+    @Override
+    public void contextDestroyed(ServletContextEvent sce) {
+    }
+
+    public static BrandResourceLinker brandResourceLinker() {
+        return new BrandResourceLinker(contextPath);
+    }
+}

jax-rs-linker/src/test/resources/mispackage/package-info.java

@@ -0,0 +1,2 @@
+@fr.vidal.oss.jax_rs_linker.api.ExposedApplication
+package mispackage;

jax-rs-linker/src/test/resources/package-info.java

@@ -0,0 +1,2 @@
+@fr.vidal.oss.jax_rs_linker.api.ExposedApplication(servletName = "my-super-application")
+package fr.vidal.oss.jax_rs_linker;