org.glassfish.apf.AnnotationProcessor Maven / Gradle / Ivy
/*
* Copyright (c) 2022 Contributors to the Eclipse Foundation
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package org.glassfish.apf;
import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.reflect.AnnotatedElement;
import java.util.logging.Level;
/**
*
* The annotation processor is the core engine to process annotations.
* All the processing configuration (input classes, error handlers, etc...)
* is provided by the ProcessingContext which can be either created from the
* createContext method or through another mean. Once the ProcessingContext has
* been initialized, it is passed to the process(ProcessingContext ctx) method which
* triggers the annotation processing.
*
*
*
* Each class accessible from the ProcessingContext.getInputScanner instance, will be
* scanned for annotations.
* Each annotation will then be processed by invoking the corresponding AnnotationHandler
* from its annotation type.
*
*
*
* The AnnotationProcessor can be configured by using the pushAnnotationHandler and
* popAnnotationHandler which allow new AnnotationHandler instances to be registered and
* unregistered for a particular annotation type.
*
*
*
* Even without reconfiguring the AnnotationProcessor instance with the above
* configuration methods, the AnnotationProcessor implementation cannot guarantee
* to be thread safe, therefore, it is encouraged the make instanciation cheap
* and users should not use the same instance concurrently.
*
*
* @author Jerome Dochez
*/
public interface AnnotationProcessor {
/**
* Creates a new empty ProcessingContext instance which can be configured
* before invoking the process() method.
*
* @return an empty ProcessingContext
*/
ProcessingContext createContext();
/**
* Starts the annotation processing tool passing the processing context which
* encapuslate all information necessary for the configuration of the tool.
*
* @param ctx is the initialized processing context
* @return the result of the annoations processing
*/
ProcessingResult process(ProcessingContext ctx) throws AnnotationProcessorException;
/**
* Process a set of classes from the parameter list rather than from the
* processing context. This allow the annotation handlers to call be the
* annotation processing tool when classes need to be processed in a
* particular context rather than when they are picked up by the scanner.
*
* @param ctx the processing context
* @param classes the list of classes to process
* @return the processing result for such classes
* @throws AnnotationProcessorException if handlers fail to process
* an annotation
*/
ProcessingResult process(ProcessingContext ctx, Class[] classes) throws AnnotationProcessorException;
/**
* Registers a new AnnotationHandler for a particular annotation type. New annotation handler
* are pushed on a List of annotation handlers for that particular annotation type, the last
* annotation handler to be registered will be invoked first and so on.
* The annotation type handled by the AnnotationHandler instance is defined
* by the getAnnotationType() method of the AnnotationHandler instance
*
* @param handler the annotation handler instance
*/
void pushAnnotationHandler(AnnotationHandler handler);
/**
* @return the top annotation handler for a particular annotation type
* @param type the annotation type
*/
AnnotationHandler getAnnotationHandler(Class type);
/**
* Unregisters the last annotation handler registered for an annotation type.
*
* @param type the annotation type.
*/
void popAnnotationHandler(Class type);
/**
* @param type the annotated element
* @return the most recent AnnotatedElement being processed which type is of the
* given ElementType or null if there is no such element in the stack of
* processed annotation elements.
*/
AnnotatedElement getLastAnnotatedElement(ElementType type);
/**
* Log a message on the default logger
*/
void log(Level level, AnnotationInfo locator, String localizedMessage);
}