A Java Protoc plugin extending generated java classes with null safe setOrClear and getOptional methods. Also works for protobuf primitive variables with the optional keyword.

You must have protoc binary installed in your system and have to download protoc-gen-java-optional executable based on platform from GitHub releases or at Files section in maven-central.

With defaults:

protoc --proto-path=./protos/ --java_out=./out/directory --plugin=protoc-gen-java-optional=./path/to/plugin/protoc-gen-java-optional.exe --java-optional_out=./out/directory ./protos/sample.proto 

With some parameters:

protoc --proto-path=./protos/ --java_out=./out/directory --plugin=protoc-gen-java-optional=./path/to/plugin/protoc-gen-java-optional.exe --java-optional_out=setter_optional=true,use_primitive_optionals=true:./out/directory ./protos/sample.proto 

<build> <extensions> <extension> <groupId>kr.motd.maven</groupId> <artifactId>os-maven-plugin</artifactId> <version>${os-maven-plugin.version}</version> </extension> </extensions> <plugins> <plugin> <groupId>org.xolstice.maven.plugins</groupId> <artifactId>protobuf-maven-plugin</artifactId> <version>${protobuf-maven-plugin.version}</version> <executions> <execution> <id>protobuf</id> <goals> <goal>compile</goal> </goals> <phase>generate-sources</phase> <configuration> <protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}</protocArtifact> <protoSourceRoot>${project.basedir}/src/test/resources/</protoSourceRoot> <useArgumentFile>true</useArgumentFile> <protocPlugins> <protocPlugin> <id>java-optional</id> <groupId>org.grpcmock</groupId> <artifactId>protoc-gen-java-optional</artifactId> <version>1.10.0</version> <mainClass>org.grpcmock.protoc.plugin.OptionalGenerator</mainClass> </protocPlugin> </protocPlugins> </configuration> </execution> </executions> </plugin> </plugins> </build>

This plugin does not support passing java protoc plugin parameters until xolstice/protobuf-maven-plugin#56 is solved, so default options will be used.

This maven plugin is not supported as it does not support running multiple output types as a single protoc command. This protoc plugin needs to be run together with the java_out target in order to extend generated classes.

• setter_object - boolean flag indicating whether to add setter methods with the nullable object itself as argument. Default true.
• setter_optional - boolean flag indicating whether to add setter methods with Optional as an argument. Default false.
• getter_optional - boolean flag indicating whether to add getter methods returning Optional. Default true.
• use_primitive_optionals - boolean flag indicating whether to use primitive optionals (OptionalInt/OptionalLong/OptionalDouble) for optional protobuf primitive's setters and getters. Default false.