JavaPoet Maven Plugin

A simple maven plugin that allows you to use JavaPoet to generate sources for a project.

To Develop a JavaFile Generator

To develop a JavaFile generator,

1. write a public static method
2. that has exactly one java.lang.String parameter and
3. returns java.lang.Iterable<com.squareup.javapoet.JavaFile>.

For example:

package your.name;

import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.TypeSpec;

import static java.util.Collections.singletonList;
import static javax.lang.model.element.Modifier.FINAL;
import static javax.lang.model.element.Modifier.PUBLIC;

public final class JavaFileFactory1 {

    private JavaFileFactory1()
    {
    }

    public static Iterable<JavaFile> javaFileIterable(final String name)
    {
        return singletonList(JavaFile.builder(
                "your.name",
                TypeSpec.classBuilder(
                        name)
                        .addModifiers(PUBLIC, FINAL)
                        .build())
                .build());
    }
}

Then, package the method as a maven dependency.

To Use

1. Update pom.xml to include a reference to the plugin repository.

   For example:

   <pluginRepositories>
       <pluginRepository>
           <releases>
               <enabled>true</enabled>
           </releases>
           <snapshots>
               <enabled>false</enabled>
           </snapshots>
           <id>ossrh</id>
           <url>https://oss.sonatype.org/service/local/staging/deploy/maven2</url>
       </pluginRepository>
       <pluginRepository>
           <releases>
               <enabled>false</enabled>
           </releases>
           <snapshots>
               <enabled>true</enabled>
           </snapshots>
           <id>ossrh-snapshot</id>
           <url>https://oss.sonatype.org/content/repositories/snapshots</url>
       </pluginRepository>
   </pluginRepositories>

2. Update pom.xml to include the plugin.

   You must configure the plugin to specify

   1. the methods to execute,
   2. the parameters to pass to the methods, and
   3. the directory for the generated .java files.

   For example:

   <plugin>
       <groupId>io.github.drewctaylor</groupId>
       <artifactId>javapoet-maven-plugin</artifactId>
       <version>1.0.5-SNAPSHOT</version>
       <configuration>
           <methods>
               <your.name.JavaFileFactory1.javaFileIterable>ClassName1</your.name.JavaFileFactory1.javaFileIterable>
               <your.name.JavaFileFactory2.javaFileIterable>ClassName2</your.name.JavaFileFactory2.javaFileIterable>
           </methods>
           <path>${project.basedir}/src/main/java</path>
       </configuration>
       <dependencies>
           <dependency>
               <groupId>your-group-id</groupId>
               <artifactId>your-artifact-id</artifactId>
               <version>your-version</version>
           </dependency>
       </dependencies>
       <executions>
           <execution>
               <goals>
                   <goal>generate-sources</goal>
               </goals>
               <phase>generate-sources</phase>
           </execution>
       </executions>
   </plugin>

   In the above example:

   The <dependencies> element specifies the dependencies that contain the methods that the plugin should invoke.

   The <methods> element contains two elements, <your.name.JavaFileFactory1.javaFileIterable> and <your.name.JavaFileFactory2.javaFileIterable>. The names of the elements specify the methods the plugin should invoke (method: javaFileIterable; class: JavaFileFactory1; package: your.name), and the content of the element indicates the value the plugin should pass to the method (ClassName1).

   The <path> element specifies the directory to which the plugin should write the generated .java files.