library maven project setup

Initial setup

This section describes how to set up a project using Apache Maven as a build tool.

Java 8 and maven should be installed in the system and properly configured.

Epigraph should be available from the maven repositories. You can install it locally to achieve this:

• git clone [email protected]:SumoLogic/epigraph.git
• cd epigraph
• mvn install

Install Epigraph IDEA plugin if you're using IntelliJ, it is available from the project github page.

Source code for this example is in the examples/library folder, in order to build and run it:

• cd examples/library
• mvn install
• mvn -pl library-service exec:java

Project structure

Project consists of two modules:

• library-schema contains Epigraph schema definition: language-agnostic data structures declarations and service APIs. This module is used by library-service to generate implementation bindings and should also be distributed to the clients for client bindings generation
• library-service contains generated Java bindings and service implementation code plus a main class which starts Undertow server with Epigraph handler.

Parent project

Parent pom.xml file has a few important things. First is a list of modules in the project:

  <modules>
    <module>library-schema</module>
    <module>library-service</module>
  </modules>

Then there are some properties which tell Maven to use Java 8 and UTF-8:

  <properties>
    <!-- Java 8 required -->
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>

    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

Finally, <build><pluginManagement><plugins> section contains Epigraph plugins that will be used by the modules:

  <plugin>
    <groupId>ws.epigraph</groupId>
    <artifactId>epigraph-maven-plugin</artifactId>
    <version>0.0.2-SNAPSHOT</version>
    <executions>
      <execution>
        <goals>
          <goal>compile</goal>
          <goal>testCompile</goal>
        </goals>
      </execution>
    </executions>
  </plugin>

  <plugin>
    <groupId>ws.epigraph</groupId>
    <artifactId>epigraph-java-maven-plugin</artifactId>
    <version>0.0.2-SNAPSHOT</version>
    <executions>
      <execution>
        <goals>
          <goal>generate-sources</goal>
        </goals>
      </execution>
    </executions>
  </plugin>

epigraph-maven-plugin compiles schema files validating them for errors and packages them in a jar artifact for publishing and distribution

epigraph-java-maven-plugin generates Java bindings

Library-schema module

library-schema pom sets artifact ID to be examples-library-schema to keep naming scheme used by other examples:

  <artifactId>examples-library-schema</artifactId>

Then it declares a dependency on Epigrph built-in types

  <dependencies>
    <dependency>
      <groupId>ws.epigraph</groupId>
      <artifactId>epigraph-builtin-types-schema</artifactId>
      <version>0.0.2-SNAPSHOT</version>
    </dependency>
  </dependencies>

In build section redefines source folder locations to be more Epigraph friendly

  <sourceDirectory>${project.basedir}/src/main/epigraph</sourceDirectory>
  <testSourceDirectory>${project.basedir}/src/test/epigraph</testSourceDirectory>

And tells Maven to use epigraph-maven-plugin

  <plugins>
    <plugin>
      <groupId>ws.epigraph</groupId>
      <artifactId>epigraph-maven-plugin</artifactId>
    </plugin>
  </plugins>

Library-service module

library-service pom sets artifact ID to be examples-library-service

  <artifactId>examples-library-service</artifactId>

Then it defines some dependencies. First one is on library-schema

  <dependency>
    <groupId>${project.parent.groupId}</groupId>
    <artifactId>examples-library-schema</artifactId>
    <version>${project.parent.version}</version>
  </dependency>

Second one is on Epigraph Undertow-based server implementation

  <dependency>
    <groupId>ws.epigraph</groupId>
    <artifactId>epigraph-java-http-server-undertow</artifactId>
    <version>0.0.2-SNAPSHOT</version>
  </dependency>

And a simple backend for SLF4J logging.

  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
    <version>1.7.22</version>
  </dependency>

Finally plugins section includes epigraph-java-maven plugin plus exec-maven-plugin so we can easily run the service:

  <plugins>

    <plugin>
      <groupId>ws.epigraph</groupId>
      <artifactId>epigraph-java-maven-plugin</artifactId>
      <configuration><server/></configuration>
    </plugin>

    <plugin>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>exec-maven-plugin</artifactId>
      <version>1.2.1</version>
      <configuration>
        <mainClass>ws.epigraph.examples.library.LibraryServer</mainClass>
      </configuration>
    </plugin>

  </plugins>

Epigraph plugin configuration includes an empty <server/> tag which tells to generate implementation stubs for all services.

Next section: schema module