From 7bc705da95829aafecfb00dd178c9cd4869f13f7 Mon Sep 17 00:00:00 2001
From: Cedric Beust <cedric@beust.com>
Date: Sat, 14 Nov 2015 05:14:29 -0800
Subject: [PATCH] =?UTF-8?q?Generate=20the=20file.=E2=80=A8?=
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---
 .../beust/apt/processor/MainProcessor.java    | 52 +++++++++++++++++--
 1 file changed, 48 insertions(+), 4 deletions(-)

diff --git a/processor/src/main/java/com/beust/apt/processor/MainProcessor.java b/processor/src/main/java/com/beust/apt/processor/MainProcessor.java
index 5abaccb..5704cc4 100644
--- a/processor/src/main/java/com/beust/apt/processor/MainProcessor.java
+++ b/processor/src/main/java/com/beust/apt/processor/MainProcessor.java
@@ -1,26 +1,70 @@
 package com.beust.apt.processor;
 
-import javax.annotation.processing.AbstractProcessor;
-import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.*;
 import javax.lang.model.SourceVersion;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ElementKind;
+import javax.lang.model.element.PackageElement;
 import javax.lang.model.element.TypeElement;
+import javax.lang.model.util.Elements;
+import javax.lang.model.util.Types;
+import javax.tools.JavaFileObject;
+import java.io.BufferedWriter;
+import java.io.IOException;
 import java.util.HashSet;
 import java.util.Set;
 
 public class MainProcessor extends AbstractProcessor {
+    private Types typeUtils;
+    private Elements elementUtils;
+    private Filer filer;
+    private Messager messager;
+
     public MainProcessor() {
         System.out.println("Instantiating MainProcessor");
     }
 
+    @Override
+    public synchronized void init(ProcessingEnvironment processingEnv) {
+        super.init(processingEnv);
+        typeUtils = processingEnv.getTypeUtils();
+        elementUtils = processingEnv.getElementUtils();
+        filer = processingEnv.getFiler();
+        messager = processingEnv.getMessager();
+    }
+
     @Override
     public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
-        System.out.println("Processing annotations $annotations");
+        for (Element annotatedElement : roundEnv.getElementsAnnotatedWith(Version.class)) {
+            Version version = annotatedElement.getAnnotation(Version.class);
+            if (annotatedElement.getKind() == ElementKind.CLASS) {
+                Element enclosing = annotatedElement.getEnclosingElement();
+                if (enclosing.getKind() == ElementKind.PACKAGE) {
+                    PackageElement packageElement = (PackageElement) enclosing;
+                    String packageName = packageElement.getQualifiedName().toString();
+                    JavaFileObject jfo = null;
+                    try {
+                        System.out.println("version = " + version.value());
+                        jfo = filer.createSourceFile(packageName + ".GeneratedVersion");
+                        BufferedWriter writer = new BufferedWriter(jfo.openWriter());
+                        writer.write("package " + packageName + ";\n\n");
+                        writer.write("public class GeneratedVersion {\n");
+                        writer.write("    public static final String VERSION = \"" + version.value() + "\";\n");
+                        writer.write("}\n");
+                        writer.close();
+                        System.out.println("Generated " + jfo.getName());
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    }
+                }
+            }
+        }
         return true;
     }
 
     public Set<String> getSupportedAnnotationTypes() {
         Set<String> result = new HashSet<>();
-        result.add("Version");
+        result.add(Version.class.getCanonicalName());
         return result;
     }