Minor improvements.

README.md

@@ -7,7 +7,27 @@ There are two modules in this project:
 - The processor (`processor/`)
 - The example using the processor (`example/`)
 
-The `processor` project defines an annotation `@Version` that lets you specify a version number. When the annotation processor is run, it generates a source file `GeneratedVersion.java` with a static field containing that version number.
+The `processor` project defines an annotation `@Version` that lets you specify a version number in two ways:
+
+- Either provide a `value` for the version.
+- Or you provide a `fileName` pointing to a `Properties` file. This file contains the version number either with the default key `version` or with your own key, which you can specify with the `propertyName` attribute.
+
+For example:
+
+```
+@Version(fileName = "example/src/main/properties/version.properties",
+    propertyName = "example.version")
+public class A {
+// ...
+```
+
+And the content of the `version.properties` file:
+
+```
+example.version=1.4
+```
+
+When the annotation processor is run, it generates a source file `GeneratedVersion.java` with a static field containing that version number.
 
 The `example` project has a single class `Example` which is annotated with `@Version` and which then displays the value of the version from the `GeneratedVersion` generated class.
 

example/src/main/java/com/beust/apt/example/Example.java

@@ -4,24 +4,25 @@ import com.beust.apt.processor.Version;
 
 import java.io.File;
 
-@Version("1.3")
+@Version(fileName = "example/src/main/properties/version.properties", propertyName = "example.version")
 class Example {
     public Example() {
         System.out.println("Instantiating Example");
     }
 
     public static void main(String[] argv) throws Exception {
-        // Uncomment these lines and launch this class to debug the annotation processor.
+        String root = "/Users/cbeust/java/java-apt-example/";
-//        String[] args = new String[] {
+        String[] args = new String[] {
-////                "-proc:only",
+                "-classpath",
-//                "-classpath", "/Users/beust/home/java/java-apt-example/processor/kobaltBuild/libs/processor-0.1.jar",
+                root + "processor/kobaltBuild/libs/processor-0.1.jar",
-//                "-processor", "com.beust.apt.processor.MainProcessor",
+                "-processor", "com.beust.apt.processor.VersionProcessor",
-//                "/Users/beust/java/java-apt-example/example/src/main/java/com/beust/apt/example/Example.java"
+                root + "example/src/main/java/com/beust/apt/example/Example.java"
-//        };
+        };
+        // Uncomment this line and launch this class to debug the annotation processor.
 //        com.sun.tools.javac.Main.main(args);
 
         File file = new File(".");
         System.out.println("Version generated: " + GeneratedVersion.VERSION);
-        new Example();
+//        new Example();
     }
 }

example/src/main/properties/version.properties

@@ -0,0 +1 @@
+example.version=1.4

processor/src/main/java/com/beust/apt/processor/MainProcessor.java

@@ -1,79 +0,0 @@
-package com.beust.apt.processor;
-
-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() {
-        log("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) {
-        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 {
-                        log("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();
-                        log("Generated " + jfo.getName());
-                    } catch (IOException e) {
-                        e.printStackTrace();
-                    }
-                }
-            }
-        }
-        return true;
-    }
-
-    public Set<String> getSupportedAnnotationTypes() {
-        Set<String> result = new HashSet<>();
-        result.add(Version.class.getCanonicalName());
-        return result;
-    }
-
-    @Override
-    public SourceVersion getSupportedSourceVersion() {
-        return SourceVersion.RELEASE_7;
-    }
-
-    private static void log(String s) {
-        System.out.println("[MainProcessor] " + s);
-    }
-}

processor/src/main/java/com/beust/apt/processor/Version.java

@@ -8,5 +8,7 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
 public @interface Version {
-    String value();
+    String value() default "";
+    String fileName() default "version.properties";
+    String propertyName() default "version";
 }

processor/src/main/java/com/beust/apt/processor/VersionProcessor.java

@@ -0,0 +1,116 @@
+package com.beust.apt.processor;
+
+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.Diagnostic;
+import javax.tools.JavaFileObject;
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Properties;
+import java.util.Set;
+
+public class VersionProcessor extends AbstractProcessor {
+    private Types typeUtils;
+    private Elements elementUtils;
+    private Filer filer;
+    private Messager messager;
+
+    @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) {
+        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 {
+                        String versionValue = findVersionValue(version);
+                        if (versionValue != null) {
+                            log("Version value found: " + versionValue);
+                            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 = \"" + versionValue + "\";\n");
+                            writer.write("}\n");
+                            writer.close();
+                            log("Generated " + jfo.getName());
+                        } else {
+                            error("Need to specify either @Version(value) or @Version(fileName)");
+                        }
+                    } catch (IOException e) {
+                        error("IOException while running", e);
+                    }
+                }
+            }
+        }
+        return true;
+    }
+
+    private boolean isDefault(String s) {
+        return s.length() == 0;
+    }
+
+    private String findVersionValue(Version version) throws IOException {
+        if (! isDefault(version.value())) {
+            return version.value();
+        } else if (! isDefault(version.fileName())) {
+            File f = new File(version.fileName());
+            if (f.exists()) {
+                log("Found " + f);
+                Properties p = new Properties();
+                p.load(new FileReader(f));
+                String result = p.getProperty(version.propertyName());
+                return result;
+            } else {
+                error("Couldn't find " + version.fileName());
+            }
+        }
+
+        return null;
+    }
+
+    public Set<String> getSupportedAnnotationTypes() {
+        Set<String> result = new HashSet<>();
+        result.add(Version.class.getCanonicalName());
+        return result;
+    }
+
+    @Override
+    public SourceVersion getSupportedSourceVersion() {
+        return SourceVersion.RELEASE_8;
+    }
+
+    private void log(String s) {
+        messager.printMessage(Diagnostic.Kind.OTHER, "[VersionProcessor] " + s);
+//        System.out.println("[VersionProcessor] " + s);
+    }
+
+    private void error(String s) {
+        error(s, null);
+    }
+
+    private void error(String s, Throwable t) {
+        messager.printMessage(Diagnostic.Kind.ERROR, s + " " + (t != null ? t.getMessage() : ""));
+    }
+}

processor/src/main/resources/META-INF/services/javax.annotation.processing.Processor

@@ -1 +1 @@
-com.beust.apt.processor.MainProcessor
+com.beust.apt.processor.VersionProcessor