auto add maven plugin

pom.xml

@@ -124,5 +124,18 @@
     </profile>
   </profiles>
 
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <compilerArgs>
+            <arg>-AbuildPlugin=false</arg>
+          </compilerArgs>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
 </project>
 

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

@@ -0,0 +1,59 @@
+package io.ebean.querybean.generator;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
+
+final class PomPluginWriter {
+
+  private static final String PLUGIN =
+      "  <!-- generated by ebean query generator -->\n"
+          + "      <plugin>\n"
+          + "        <groupId>io.ebean</groupId>\n"
+          + "        <artifactId>ebean-maven-plugin</artifactId>\n"
+          + "        <version>%s</version>\n"
+          + "        <executions>\n"
+          + "          <execution>\n"
+          + "            <!-- Will enhance entity classes to add missing spi provides -->"
+          + "            <goals>\n"
+          + "              <goal>enhance</goal>\n"
+          + "              <goal>testEnhance</goal>\n"
+          + "            </goals>\n"
+          + "          </execution>\n"
+          + "        </executions>\n"
+          + "      </plugin>\n"
+          + "    ";
+
+  static void addPlugin2Pom() throws IOException {
+
+    if (disabled()) {
+      return;
+    }
+
+    var pomPath = APContext.getBuildResource("").getParent().resolve("pom.xml");
+    if (!pomPath.toFile().exists()) {
+      return;
+    }
+
+    var pomContent = Files.readString(pomPath);
+    // if not already present in pom.xml
+    if (pomContent.contains("ebean-maven-plugin")) {
+      return;
+    }
+    APContext.logNote("Adding ebean-maven-plugin to pom");
+    var pluginsIndex = pomContent.indexOf("</plugins>");
+    var builder = new StringBuilder(pomContent);
+    if (pluginsIndex != -1) {
+      builder.insert(
+          pluginsIndex,
+          String.format(PLUGIN, PomPluginWriter.class.getPackage().getImplementationVersion()));
+
+      Files.writeString(
+          pomPath, builder.toString(), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
+    }
+  }
+
+  private static boolean disabled() {
+    return !APContext.getOption("buildPlugin").map(Boolean::valueOf).orElse(true);
+  }
+}

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

@@ -3,15 +3,21 @@
 import static io.ebean.querybean.generator.APContext.logError;
 import static io.ebean.querybean.generator.APContext.logNote;
 import static io.ebean.querybean.generator.APContext.typeElement;
+import static java.util.stream.Collectors.joining;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
 import java.util.Arrays;
 import java.util.Optional;
 import java.util.Set;
+import java.util.stream.Stream;
 
 import javax.annotation.processing.AbstractProcessor;
 import javax.annotation.processing.ProcessingEnvironment;
 import javax.annotation.processing.RoundEnvironment;
 import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.annotation.processing.SupportedOptions;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.TypeElement;
@@ -24,6 +30,7 @@
 @GenerateUtils
 @GenerateAPContext
 @GenerateModuleInfoReader
+@SupportedOptions("buildPlugin")
 @SupportedAnnotationTypes({
   ConverterPrism.PRISM_TYPE,
   EbeanComponentPrism.PRISM_TYPE,
@@ -39,6 +46,26 @@ public class Processor extends AbstractProcessor implements Constants {
   public synchronized void init(ProcessingEnvironment processingEnv) {
     super.init(processingEnv);
     ProcessingContext.init(processingEnv);
+    try {
+
+      // write a note in target so that other apts can know spi is running
+      var file = APContext.getBuildResource("avaje-processors.txt");
+      var addition = new StringBuilder();
+      //if file exists, dedup and append current processor
+      if (file.toFile().exists()) {
+        var result =
+          Stream.concat(Files.lines(file), Stream.of("ebean-querybean-generator"))
+            .distinct()
+            .collect(joining("\n"));
+        addition.append(result);
+      } else {
+        addition.append("ebean-querybean-generator");
+      }
+      Files.writeString(file, addition.toString(), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
+      PomPluginWriter.addPlugin2Pom();
+    } catch (IOException e) {
+      // not an issue worth failing over
+    }
   }
 
   @Override