capnp-maven-plugin

Description

The Cap'n Proto maven plugin provides dynamic compilation of capnproto's definition schemas at build time. Generated java classes are automatically added to project source.

The plugin handles its M2E build lifecycle.

Usage

---

The simplest configuration will compile all schema definition files contained in default schema directory.

<plugin>
    <groupId>org.expretio.maven.plugins</groupId>
    <artifactId>capnp-maven-plugin</artifactId>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
</plugin>

The Cap'n Proto Java runtime dependency is needed.

<dependency>
    <groupId>org.capnproto</groupId>
    <artifactId>runtime</artifactId>
    <version>0.1.1</version>
</dependency>

Goal generate

Attributes

• Requires a Maven project to be executed.
• Requires dependency resolution of artifacts in scope: runtime.
• The goal is thread-safe and supports parallel builds.
• Binds by default to the lifecycle phase: generate-sources.

Configuration

name	type	Since	Description
outputDirectory	File	1.0	Output directory of generated java classes. Default: ${project.build.directory}/generated-sources/capnp
schemaDirectory	File	1.0	Base directory of definition schemas. Default: src/main/capnp
workDirectory	File	1.0	Compilation process working directory. Default: ${project.build.directory}/capnp-work
schemaFileExtension	String	1.0	Extension of definition schema files. Default: capnp Example: foo.capnp
schemas	File[ ]	1.0	Explicitly specified definition schema files. If none, all files matching schemaFileExtension under schemaDirectory will be compiled. Files must be specified relatively from schemaDirectory.
importDirectories	File[ ]	1.0	Supplementary import directories. Note: schemaDirectory is implicitly considered as an import directory..
nativeDependencyVersion	String	1.0	Version of the org.expretio.maven:capnp-natives dependency.
nativeDependencyClassifier	String	1.0	Classifier of the org.expretio.maven:capnp-natives dependency, forcing the targeted platform when specified. It is recommended to use the default value, which adjusts the classifier to current platform automatically. Default: auto
handleNativeDependency	Boolean	1.0	Set to false to configure manually the org.expretio.maven:capnp-natives dependency. Default: true
verbose	Boolean	1.0	Set to false for no output. Default: true

Example - Compiling selected schemas

Use schemas to explicitly specify which schemas to be compiled.

<plugin>
    <groupId>org.expretio.maven.plugins</groupId>
    <artifactId>capnp-maven-plugin</artifactId>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
            <configuration>
                <schemas>
                    <schema>org/expretio/one/foo.capnp</schema>
                </schemas>
            </configuration>
        </execution>
    </executions>
</plugin>

Example - Using java.capnp

The java.capnp schema, providing package and outerClassname annotations, is available at the root of working directory. The following schema illustrates how to import it.

file: ${schemaDirectory}/org/expretio/one/foo.capnp

@0xe9e172ef0f0049f6;

using Java = import "/java.capnp";

$Java.package("org.expretio.one");
$Java.outerClassname("Foo");

struct FooStruct
{
    code @0 :Text;
}

Example - Interdependent schemas

Suppose schema bar.capnp depends on FooStruct defined in foo.capnp.

file: ${schemaDirectory}/org/expretio/one/foo.capnp

@0xe9e172ef0f0049f6;

using Java = import "/java.capnp";

$Java.package("org.expretio.one");
$Java.outerClassname("Foo");

struct FooStruct
{
    code @0 :Text;
}

file: ${schemaDirectory}/org/expretio/two/bar.capnp

@0xb5724e25782451a6;

using Java = import "/java.capnp";

using import "/org/expretio/one/foo.capnp".FooStruct;

$Java.package("org.expretio.two");
$Java.outerClassname("Bar");

struct BarStruct
{
    foo @0 :FooStruct;
}

Supported platforms

• Linux 64-bit
• Windows
• OS X 64-bit