Merge pull request #3580 from SentryMan/feature/lookup-generation

[querybean-generator] Generate lookup for modules

Author: rbygrave

querybean-generator/src/main/java/io/ebean/querybean/generator/LookupWriter.java

@@ -0,0 +1,83 @@
+package io.ebean.querybean.generator;
+
+import static java.util.function.Predicate.not;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.Collection;
+import java.util.Set;
+
+import javax.annotation.processing.RoundEnvironment;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.util.Elements;
+import javax.tools.FileObject;
+
+/** Write the source code for the factory. */
+class LookupWriter {
+  private LookupWriter() {}
+
+  private static final String METAINF_SERVICES_LOOKUP =
+      "META-INF/services/io.ebean.config.LookupProvider";
+
+  private static final String FILE_STRING =
+      "package %s;\n"
+          + "\n"
+          + "import java.lang.invoke.MethodHandles;\n"
+          + "\n"
+          + "import io.ebean.config.LookupProvider;\n"
+          + "\n"
+          + "public class EbeanMethodLookup implements LookupProvider {\n"
+          + "\n"
+          + "  private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();\n"
+          + "\n"
+          + "  @Override\n"
+          + "  public MethodHandles.Lookup provideLookup() {\n"
+          + "    return LOOKUP;\n"
+          + "  }\n"
+          + "}";
+
+  static void write(
+      ProcessingContext processingContext,
+      Elements util,
+      Set<? extends TypeElement> annotations,
+      RoundEnvironment roundEnv) {
+
+    var module =
+        annotations.stream()
+            .map(roundEnv::getElementsAnnotatedWith)
+            .filter(not(Collection::isEmpty))
+            .findAny()
+            .map(s -> s.iterator().next())
+            .map(util::getModuleOf)
+            .orElse(null);
+
+    if (module != null && !module.isUnnamed()) {
+      var moduleNameString = module.getQualifiedName().toString();
+
+      var pkg = moduleNameString + ".lookup";
+      String fqn = pkg + ".EbeanMethodLookup";
+      try {
+        var javaFileObject = processingContext.createWriter(fqn);
+
+        var writer = new Append(javaFileObject.openWriter());
+
+        writer.append(FILE_STRING, pkg);
+        writer.close();
+        writeServicesFile(processingContext, fqn);
+      } catch (IOException e) {
+        processingContext.logError(null, "Failed to write lookup class " + e.getMessage());
+      }
+    }
+  }
+
+  private static void writeServicesFile(ProcessingContext processingContext, String fqn)
+      throws IOException {
+
+    FileObject jfo = processingContext.createMetaInfWriter(METAINF_SERVICES_LOOKUP);
+    if (jfo != null) {
+      Writer writer = jfo.openWriter();
+      writer.write(fqn);
+      writer.close();
+    }
+  }
+}

querybean-generator/src/main/java/io/ebean/querybean/generator/Processor.java

@@ -20,8 +20,7 @@ public class Processor extends AbstractProcessor implements Constants {
   private SimpleModuleInfoWriter moduleWriter;
   private boolean initModuleWriter;
 
-  public Processor() {
-  }
+  private boolean wroteLookup;
 
   @Override
   public synchronized void init(ProcessingEnvironment processingEnv) {
@@ -59,6 +58,10 @@ public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment
       String msg = "Ebean APT generated %s query beans, loaded %s others - META-INF/ebean-generated-info.mf entity-packages: %s";
       processingContext.logNote(msg, count, loaded, processingContext.getAllEntityPackages());
     }
+    if (!wroteLookup) {
+      wroteLookup = true;
+      LookupWriter.write(processingContext, processingEnv.getElementUtils(), annotations, roundEnv);
+    }
     return true;
   }