spring-value-annotation-processor

Spring Configuration Extensions: Value Annotation Processor

An annotation processor to extract all configuration properties injected through Spring @Value annotations.

It generates a additional-spring-configuration-metadata.json conforming to the Configuration Metadata format defined by Spring Boot.

Usage

If using Maven, you can simply add the project as a provided dependency.

<dependency>
    <groupId>com.github.egoettelmann</groupId>
    <artifactId>spring-value-annotation-processor</artifactId>
    <version>0.2.1</version>
    <scope>provided</scope>
</dependency>

If you are using the maven-compiler-plugin for your build, you will have to declare it in the annotationProcessorPaths. The plugin's configuration should look to something like the following:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version>
    <configuration>
        <annotationProcessorPaths>
            <!-- in addition to any other annotation processor (like Lombok, etc.) -->
            <annotationProcessorPath>
                <groupId>com.github.egoettelmann</groupId>
                <artifactId>spring-value-annotation-processor</artifactId>
                <version>0.2.1</version>
            </annotationProcessorPath>
        </annotationProcessorPaths>
    </configuration>
</plugin>

After executing mvn clean package, you can find the additional-spring-configuration-metadata.json file under target/classes/META-INF/.

Additional compiler options

Following additional options are available:

Property	Type	Description
failOnError	boolean	Specifies if errors during the processing should make the build fail. Default: false.
metadataOutputFile	String	Defines a different output file. Default: META-INF/additional-spring-configuration-metadata.json.

Configuration would be as follows:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version>
    <configuration>
        <annotationProcessorPaths>
            <!-- in addition to any other annotation processor (like Lombok, etc.) -->
            <annotationProcessorPath>
                <groupId>com.github.egoettelmann</groupId>
                <artifactId>spring-value-annotation-processor</artifactId>
                <version>0.2.1</version>
            </annotationProcessorPath>
        </annotationProcessorPaths>
        <compilerArgs>
            <arg>-AfailOnError=true</arg>
            <arg>-AmetadataOutputFile=META-INF/additional4value-spring-configuration-metadata.json</arg>
        </compilerArgs>
    </configuration>
</plugin>

Known issues

List of known issues and how to avoid/fix them.

Using custom additional spring configuration metadata #10

If defining a custom additional-spring-configuration-metadata.json in your resources (as described by the Spring documentation), in combination with the spring-boot-configuration-processor, you will get following error during the build:

javax.annotation.processing.FilerException: Attempt to reopen a file for path /META-INF/additional-spring-configuration-metadata.json

This is because both annotation processors, spring-boot-configuration-processor and spring-value-annotation-processor try to create the same file. As Java specifications JSR-269 for annotation processing does not allow reopening an already written file, the execution fails.

The solution is to specify a different output file using the -AmetadataOutputFile compiler option, to prevent any conflict.