Writing an annotation processor for maven-processo

Question

I am interested in writing an annotation processor for the maven-processor-plugin. I am relatively new to Maven.

Where in the project path should the processor Java source code go (e.g.: src/main/java/...) so that it gets compiled appropriately, but does not end up as part of my artifact JAR file?

Answer 1

The easiest way is to keep your annotation processor in a separate project that you include as dependency.

If that doesn't work for you, use this config

Compiler Plugin:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    <configuration>
        <source>1.5</source>
        <target>1.5</target>
    </configuration>
    <inherited>true</inherited>
    <executions>
        <execution>
            <id>default-compile</id>
            <inherited>true</inherited>
            <configuration>
                <!-- limit first compilation run to processor -->
                <includes>path/to/processor</includes>
            </configuration>
        </execution>
        <execution>
            <id>after-processing</id>
            <phase>process-classes</phase>
            <goals>
                <goal>compile</goal>
            </goals>
            <inherited>false</inherited>
            <configuration>
                <excludes>path/to/processor</excludes>
            </configuration>
        </execution>
    </executions>
</plugin>

Processor Plugin:

<plugin>
    <groupId>org.bsc.maven</groupId>
    <artifactId>maven-processor-plugin</artifactId>
    <executions>
        <execution>
            <id>process</id>
            <goals>
                <goal>process</goal>
            </goals>
            <phase>compile</phase>
            <configuration>
                <processors>
                    <processor>com.yourcompany.YourProcessor</processor>
                </processors>
            </configuration>
        </execution>
    </executions>
</plugin>

(Note that this must be executed between the two compile runs, so it is essential that you place this code in the pom.xml after the above maven-compiler-plugin configuration)

Jar Plugin:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <version>2.3.1</version>
    <configuration>
        <excludes>path/to/processor</excludes>
    </configuration>
    <inherited>true</inherited>
</plugin>