Add Dubbo Annotation Processor (Add deprecated method warn when called by user, #10850)

NOTICE

@@ -4,7 +4,7 @@ Copyright 2018-2023 The Apache Software Foundation
 This product includes software developed at
 The Apache Software Foundation (http://www.apache.org/).
 
-This product contains code form the Netty Project:
+This product contains code from the Netty Project:
 
 The Netty Project
 =================

dubbo-annotation-processor/pom.xml

@@ -0,0 +1,165 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.apache.dubbo</groupId>
+    <artifactId>dubbo-annotation-processor</artifactId>
+    <version>1.0.0</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+
+        <!--  System dependencies may cause problems in checkstyle. -->
+        <checkstyle.skip>true</checkstyle.skip>
+        <checkstyle_unix.skip>true</checkstyle_unix.skip>
+        <rat.skip>true</rat.skip>
+        <jacoco.skip>true</jacoco.skip>
+
+        <maven.deploy.skip>true</maven.deploy.skip>
+
+        <junit_jupiter_version>5.9.0</junit_jupiter_version>
+        <javassist_version>3.29.2-GA</javassist_version>
+    </properties>
+
+    <packaging>jar</packaging>
+
+    <dependencies>
+        <!-- JUnit Jupiter Engine to depend on the JUnit5 engine and JUnit 5 API -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit_jupiter_version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit_jupiter_version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <version>${junit_jupiter_version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.javassist</groupId>
+            <artifactId>javassist</artifactId>
+            <version>${javassist_version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.10.1</version>
+                <configuration>
+                    <proc>none</proc>
+                    <fork>true</fork>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <profiles>
+        <profile>
+            <id>default-profile-in-jdk-8</id>
+            <activation>
+                <file>
+                    <exists>${java.home}/../lib/tools.jar</exists>
+                </file>
+                <jdk>(, 9)</jdk>
+            </activation>
+            <properties>
+                <toolsjar>${java.home}/../lib/tools.jar</toolsjar>
+            </properties>
+
+            <dependencies>
+                <dependency>
+                    <groupId>javac</groupId>
+                    <artifactId>javac</artifactId>
+                    <version>1.0</version>
+                    <scope>system</scope>
+                    <systemPath>${toolsjar}</systemPath>
+                </dependency>
+            </dependencies>
+        </profile>
+
+        <profile>
+            <id>legacy-apple-jdk-profile</id>
+            <activation>
+                <activeByDefault>false</activeByDefault>
+                <file>
+                    <exists>${java.home}/../Classes/classes.jar</exists>
+                </file>
+                <jdk>(, 9)</jdk>
+            </activation>
+
+            <properties>
+                <toolsjar>${java.home}/../Classes/classes.jar</toolsjar>
+            </properties>
+
+            <dependencies>
+                <dependency>
+                    <groupId>javac</groupId>
+                    <artifactId>javac</artifactId>
+                    <version>1.0</version>
+                    <scope>system</scope>
+                    <systemPath>${toolsjar}</systemPath>
+                </dependency>
+            </dependencies>
+        </profile>
+
+        <profile>
+            <id>add-export-greater-than-9</id>
+            <activation>
+                <activeByDefault>false</activeByDefault>
+                <jdk>[9, )</jdk>
+            </activation>
+
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-compiler-plugin</artifactId>
+                        <version>3.10.1</version>
+                        <configuration>
+                            <fork>true</fork>
+                            <proc>none</proc>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+
+</project>

dubbo-annotation-processor/src/main/java/org/apache/dubbo/annotation/AnnotationProcessingHandler.java

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.dubbo.annotation;
+
+import javax.lang.model.element.Element;
+import java.lang.annotation.Annotation;
+import java.util.Set;
+
+/**
+ * Represents an annotation processing handler, which is invoked by DispatchingAnnotationProcessor.
+ */
+public interface AnnotationProcessingHandler {
+
+    /**
+     * Set the annotations that this handler will handle.
+     *
+     * @return annotations to handle
+     */
+    Set<Class<? extends Annotation>> getAnnotationsToHandle();
+
+    /**
+     * Formal processing method.
+     *
+     * @param elements the elements that annotated by the annotations of getAnnotationsToHandle()
+     * @param annotationProcessorContext the annotation processor context object (Javac object encapsulation)
+     */
+    void process(Set<Element> elements,
+                 AnnotationProcessorContext annotationProcessorContext);
+}

dubbo-annotation-processor/src/main/java/org/apache/dubbo/annotation/AnnotationProcessorContext.java

@@ -0,0 +1,139 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.dubbo.annotation;
+
+import com.sun.source.util.Trees;
+import com.sun.tools.javac.api.JavacTrees;
+import com.sun.tools.javac.processing.JavacProcessingEnvironment;
+import com.sun.tools.javac.tree.TreeMaker;
+import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Names;
+
+import javax.annotation.processing.ProcessingEnvironment;
+import java.lang.reflect.Method;
+import java.util.Objects;
+
+/**
+ * The Context Object of Annotation Processor, which stores objects related to javac.
+ */
+public class AnnotationProcessorContext {
+    private JavacProcessingEnvironment javacProcessingEnvironment;
+    private JavacTrees javacTrees;
+    private TreeMaker treeMaker;
+    private Names names;
+    private Context javacContext;
+    private Trees trees;
+
+    private AnnotationProcessorContext() { }
+
+    private static <T> T jbUnwrap(Class<? extends T> iface, T wrapper) {
+        T unwrapped = null;
+        try {
+            final Class<?> apiWrappers = wrapper.getClass().getClassLoader().loadClass("org.jetbrains.jps.javac.APIWrappers");
+            final Method unwrapMethod = apiWrappers.getDeclaredMethod("unwrap", Class.class, Object.class);
+            unwrapped = iface.cast(unwrapMethod.invoke(null, iface, wrapper));
+        } catch (Throwable ignored) {
+        }
+
+        return unwrapped != null ? unwrapped : wrapper;
+    }
+
+    public static AnnotationProcessorContext fromProcessingEnvironment(ProcessingEnvironment processingEnv) {
+        AnnotationProcessorContext apContext = new AnnotationProcessorContext();
+
+        Object procEnvToUnwrap = processingEnv.getClass() == JavacProcessingEnvironment.class ?
+            processingEnv : jbUnwrap(JavacProcessingEnvironment.class, processingEnv);
+
+        JavacProcessingEnvironment jcProcessingEnvironment = (JavacProcessingEnvironment) procEnvToUnwrap;
+
+        Context context = jcProcessingEnvironment.getContext();
+
+        apContext.javacProcessingEnvironment = jcProcessingEnvironment;
+
+        apContext.javacContext = context;
+        apContext.javacTrees = JavacTrees.instance(jcProcessingEnvironment);
+        apContext.treeMaker = TreeMaker.instance(context);
+        apContext.names = Names.instance(context);
+
+        apContext.trees = Trees.instance(jcProcessingEnvironment);
+
+        return apContext;
+    }
+
+    // Auto-generated methods.
+
+    public JavacTrees getJavacTrees() {
+        return javacTrees;
+    }
+
+    public TreeMaker getTreeMaker() {
+        return treeMaker;
+    }
+
+    public Names getNames() {
+        return names;
+    }
+
+    public Context getJavacContext() {
+        return javacContext;
+    }
+
+    public Trees getTrees() {
+        return trees;
+    }
+
+    public JavacProcessingEnvironment getJavacProcessingEnvironment() {
+        return javacProcessingEnvironment;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        AnnotationProcessorContext context = (AnnotationProcessorContext) o;
+
+        if (!Objects.equals(javacTrees, context.javacTrees)) return false;
+        if (!Objects.equals(treeMaker, context.treeMaker)) return false;
+        if (!Objects.equals(names, context.names)) return false;
+        if (!Objects.equals(javacContext, context.javacContext))
+            return false;
+        return Objects.equals(trees, context.trees);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = javacTrees != null ? javacTrees.hashCode() : 0;
+        result = 31 * result + (treeMaker != null ? treeMaker.hashCode() : 0);
+        result = 31 * result + (names != null ? names.hashCode() : 0);
+        result = 31 * result + (javacContext != null ? javacContext.hashCode() : 0);
+        result = 31 * result + (trees != null ? trees.hashCode() : 0);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "AnnotationProcessorContext{" +
+            "javacTrees=" + javacTrees +
+            ", treeMaker=" + treeMaker +
+            ", names=" + names +
+            ", javacContext=" + javacContext +
+            ", trees=" + trees +
+            '}';
+    }
+}