Revapi Java SPI

<project>
    <modelVersion>4.0.0</modelVersion>

    <groupId>my.group</groupId>
    <artifactId>my.extension</artifactId>
    <version>1.0.0</version>

    <dependencies>
        <dependency>
            <groupId>org.revapi</groupId>
            <artifactId>revapi-java-spi</artifactId>
            <version>0.23.4</version>
        </dependency>
    </dependencies>
</project>

package my.extension;

import java.io.Reader;
import java.util.regex.Pattern;

import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.ExecutableElement;

import org.revapi.AnalysisContext;
import org.revapi.Difference;
import org.revapi.DifferenceTransform;
import org.revapi.java.spi.JavaMethodElement;
import org.revapi.java.spi.Util;

public class IgnoreNewMethodsOnEJBInterfaces implements DifferenceTransform<JavaMethodElement> {
    @Override
    public Pattern[] getDifferenceCodePatterns() {
        return new Pattern[] { Pattern.compile("java\\.method\\.addedToInterface") };
    }

    @Override
    public Difference transform(JavaMethodElement oldElement, JavaMethodElement newElement,
        Difference difference) {

        // we know the element will be a JavaMethodElement. This is because we limit the
        // differences passed into this method.
        ExecutableElement method = newElement.getDeclaringElement();

        // ok, so we got a reference to the method that caused the difference. Now we need to
        // check whether the method was added to an EJB interface - we will just check whether
        // the interface was annotated with the @Local or @Remote annotations.
        for (AnnotationMirror annotation : method.getEnclosingElement().getAnnotationMirrors()) {
            // the Util class in the Java SPI provides a number of useful methods to ease the work
            // with the javax.lang.model objects.
            String annotationTypeName = Util.toHumanReadableString(annotation.getAnnotationType());
            if ("javax.ejb.Local".equals(annotationTypeName) ||
                "javax.ejb.Remote".equals(annotationTypeName)) {

                // ok, so we've found out that the type that declared the new method is indeed
                // an EJB interface. By returning null, we tell Revapi to remove this difference.
                return null;
            }
        }

        // ok, this is not an EJB interface, so we leave the difference alone
        return difference;
    }

    @Override
    public void close() throws Exception {
        // no resources to close...
    }

    @Override
    public String[] getConfigurationRootPaths() {
        // no configuration possible
        return null;
    }

    @Override
    public Reader getJSONSchema(String configurationRootPath) {
        // no configuration possible
        return null;
    }

    @Override
    public void initialize(AnalysisContext analysisContext) {
        // nothing needed here
    }
}