Annotations Processor Tools (APT)
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The document discusses annotation processing tools (APT). It begins by defining what an annotation is and how they are used. It then covers retention policies, how annotations can be accessed at runtime via reflection, and the Mirror API. The bulk of the document provides an example of creating a custom annotation processor for Android data binding. It demonstrates creating annotations, configuring a processor, processing annotation elements, and generating code. The key aspects covered are how to implement an annotation processor by extending AbstractProcessor and processing annotation elements in the RoundEnvironment.
Annotations Processor Tools (APT)
- 3. Agenda 1. Annotation Processing Tool 2. Discusión 3. Caso práctico
- 4. ¿Qué es eso de APT?
- 5. public @interface DummyAnnotiation {} Anotación
- 6. Retención • Constructor • Atributo • Variable • Método • Parámetro • Etc. • Source • Class • Runtime Objetivo
- 7. Anotación @Retention(CLASS) @Target(FIELD) public @interface InjectView { int value(); }
- 8. Runtime Class tiene la magia: • getAnnotation(Class<T> annotationType) • getAnnotations() • getDeclaredAnnotations() • isAnnotationPresent(Class<T> annotationType)
- 10. Discusión
- 11. Caso Práctico
- 13. Creando Anotaciones @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface Mappable { Class<?> with(); }
- 14. Creando Anotaciones @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface Mappable { Class<?> with(); }
- 15. Configurando las Anotaciones @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface Mappable { Class<?> with(); }
- 16. Configurando las Anotaciones @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface Mappable { Class<?> with(); }
- 17. @SupportedSourceVersion(SourceVersion.RELEASE_7) @SupportedAnnotationTypes({ "com.mobandme.android.transformer.compiler.Mapping", "com.mobandme.android.transformer.compiler.Mappable", "com.mobandme.android.transformer.compiler.Parse" }) public class AnnotationsProcessor extends AbstractProcessor { RoundEnvironment roundEnvironment; Map<String, MapperInfo> mappersList; @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { return true; } Creando el Procesador
- 18. @SupportedSourceVersion(SourceVersion.RELEASE_7) @SupportedAnnotationTypes({ "com.mobandme.android.transformer.compiler.Mapping", "com.mobandme.android.transformer.compiler.Mappable", "com.mobandme.android.transformer.compiler.Parse" }) public class AnnotationsProcessor extends AbstractProcessor { RoundEnvironment roundEnvironment; Map<String, MapperInfo> mappersList; @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { return true; } Creando el Procesador
- 19. @SupportedSourceVersion(SourceVersion.RELEASE_7) @SupportedAnnotationTypes({ "com.mobandme.android.transformer.compiler.Mapping", "com.mobandme.android.transformer.compiler.Mappable", "com.mobandme.android.transformer.compiler.Parse" }) public class AnnotationsProcessor extends AbstractProcessor { RoundEnvironment roundEnvironment; Map<String, MapperInfo> mappersList; @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { return true; } Configurando el Procesador
- 20. Implementando el Procesador @SupportedSourceVersion(SourceVersion.RELEASE_7) @SupportedAnnotationTypes({ "com.mobandme.android.transformer.compiler.Mapping", "com.mobandme.android.transformer.compiler.Mappable", "com.mobandme.android.transformer.compiler.Parse" }) public class AnnotationsProcessor extends AbstractProcessor { RoundEnvironment roundEnvironment; Map<String, MapperInfo> mappersList; @Override public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { return true; }
- 21. Implementando el Procesador private void processMappedAnnotationElements() { Set<? extends Element> elements = roundEnvironment.getElementsAnnotatedWith(Mapped.class); for (Element mappedElement : elements) { if (mappedElement.getKind() == ElementKind.FIELD) { Mapped mappedAnnotation = mappedElement.getAnnotation(Mapped.class); String toFieldName = mappedAnnotation.toField(); } } }
- 22. Implementando el Procesador private void processMappedAnnotationElements() { Set<? extends Element> elements = roundEnvironment.getElementsAnnotatedWith(Mapped.class); for (Element mappedElement : elements) { if (mappedElement.getKind() == ElementKind.FIELD) { Mapped mappedAnnotation = mappedElement.getAnnotation(Mapped.class); String toFieldName = mappedAnnotation.toField(); } } }
- 23. Implementando el Procesador private void processMappedAnnotationElements() { Set<? extends Element> elements = roundEnvironment.getElementsAnnotatedWith(Mapped.class); for (Element mappedElement : elements) { if (mappedElement.getKind() == ElementKind.FIELD) { Mapped mappedAnnotation = mappedElement.getAnnotation(Mapped.class); String toFieldName = mappedAnnotation.toField(); } } }
- 24. Implementando el Procesador private void processMappedAnnotationElements() { Set<? extends Element> elements = roundEnvironment.getElementsAnnotatedWith(Mapped.class); for (Element mappedElement : elements) { if (mappedElement.getKind() == ElementKind.FIELD) { Mapped mappedAnnotation = mappedElement.getAnnotation(Mapped.class); String toFieldName = mappedAnnotation.toField(); } } }
- 25. Generando el Código JavaFileObject file = processingEnv.getFiler().createSourceFile(name); BufferedWriter buffer = new BufferedWriter(file.openWriter()); //… buffer.close();
- 27. Configuración de Gradle para el Compilador buildscript { repositories { maven { url "https://oss.sonatype.org/content/repositories/snapshots/" } jcenter() } dependencies { classpath 'com.jimdo.gradle:gradle-apt-plugin:0.5-SNAPSHOT' } } apply plugin: 'java' apply plugin: 'apt'
- 29. ¿Preguntas?