io.virtdata.processors.FunctionManifestProcessor Maven / Gradle / Ivy
package io.virtdata.processors;
import javax.annotation.processing.*;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic;
import javax.tools.StandardLocation;
import java.io.Writer;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
/**
* This annotation processor is responsible for finding all annotated functions and adding
* them to the manifest file for the current project.
* Specifically, any class annotated as {@link io.virtdata.annotations.ThreadSafeMapper}
* or {@link io.virtdata.annotations.PerThreadMapper} are recorded in
* classes/META-INF/functions
*
* This operates slightly differently than the service loader facility. The point is to
* enumerate candidate functions without requiring them to have a no-args constructor.
*/
@SupportedOptions({"title"})
@SupportedSourceVersion(SourceVersion.RELEASE_11)
@SupportedAnnotationTypes({
"io.virtdata.annotations.ThreadSafeMapper",
"io.virtdata.annotations.PerThreadMapper"})
public class FunctionManifestProcessor extends AbstractProcessor {
private Filer filer;
private Messager messenger;
private Writer writer;
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
this.filer = processingEnv.getFiler();
this.messenger = processingEnv.getMessager();
}
@SuppressWarnings("unchecked")
@Override
public boolean process(Set annotations, RoundEnvironment roundEnv) {
List ts = new ArrayList<>();
try {
if (writer==null) {
writer = filer.createResource(StandardLocation.CLASS_OUTPUT, "", "META-INF/functions")
.openWriter();
}
for (String annotationType : this.getSupportedAnnotationTypes()) {
Class annotationClass =
(Class) Class.forName(annotationType);
Set tsms = roundEnv.getElementsAnnotatedWith(annotationClass);
if (tsms.size() > 0) {
for (Element e : tsms) {
writer.write(((TypeElement) e).getQualifiedName() + "\n");
}
}
}
writer.close();
} catch (Exception e) {
messenger.printMessage(Diagnostic.Kind.ERROR, e.toString());
}
return false;
}
}