duke@1: /*
duke@1:  * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
duke@1:  * published by the Free Software Foundation.  Sun designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
duke@1:  * by Sun in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
duke@1:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@1:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@1:  * have any questions.
duke@1:  */
duke@1: 
duke@1: package javax.annotation.processing;
duke@1: 
duke@1: import java.util.Set;
duke@1: import java.util.HashSet;
duke@1: import java.util.Collections;
duke@1: import javax.lang.model.element.*;
duke@1: import javax.lang.model.SourceVersion;
duke@1: import javax.tools.Diagnostic;
duke@1: 
duke@1: /**
duke@1:  * An abstract annotation processor designed to be a convenient
duke@1:  * superclass for most concrete annotation processors.  This class
duke@1:  * examines annotation values to compute the {@linkplain
duke@1:  * #getSupportedOptions options}, {@linkplain
duke@1:  * #getSupportedAnnotationTypes annotations}, and {@linkplain
duke@1:  * #getSupportedSourceVersion source version} supported by its
duke@1:  * subtypes.
duke@1:  *
duke@1:  * <p>The getter methods may {@linkplain Messager#printMessage issue
duke@1:  * warnings} about noteworthy conditions using the facilities available
duke@1:  * after the processor has been {@linkplain #isInitialized
duke@1:  * initialized}.
duke@1:  *
duke@1:  * <p>Subclasses are free to override the implementation and
duke@1:  * specification of any of the methods in this class as long as the
duke@1:  * general {@link javax.annotation.processing.Processor Processor}
duke@1:  * contract for that method is obeyed.
duke@1:  *
duke@1:  * @author Joseph D. Darcy
duke@1:  * @author Scott Seligman
duke@1:  * @author Peter von der Ah&eacute;
duke@1:  * @since 1.6
duke@1:  */
duke@1: public abstract class AbstractProcessor implements Processor {
duke@1:     /**
duke@1:      * Processing environment providing by the tool framework.
duke@1:      */
duke@1:     protected ProcessingEnvironment processingEnv;
duke@1:     private boolean initialized = false;
duke@1: 
duke@1:     /**
duke@1:      * Constructor for subclasses to call.
duke@1:      */
duke@1:     protected AbstractProcessor() {}
duke@1: 
duke@1:     /**
duke@1:      * If the processor class is annotated with {@link
duke@1:      * SupportedOptions}, return an unmodifiable set with the same set
duke@1:      * of strings as the annotation.  If the class is not so
duke@1:      * annotated, an empty set is returned.
duke@1:      *
duke@1:      * @return the options recognized by this processor, or an empty
duke@1:      * set if none
duke@1:      */
duke@1:     public Set<String> getSupportedOptions() {
duke@1:         SupportedOptions so = this.getClass().getAnnotation(SupportedOptions.class);
duke@1:         if  (so == null)
duke@1:             return Collections.emptySet();
duke@1:         else
duke@1:             return arrayToSet(so.value());
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * If the processor class is annotated with {@link
duke@1:      * SupportedAnnotationTypes}, return an unmodifiable set with the
duke@1:      * same set of strings as the annotation.  If the class is not so
duke@1:      * annotated, an empty set is returned.
duke@1:      *
duke@1:      * @return the names of the annotation types supported by this
duke@1:      * processor, or an empty set if none
duke@1:      */
duke@1:     public Set<String> getSupportedAnnotationTypes() {
duke@1:             SupportedAnnotationTypes sat = this.getClass().getAnnotation(SupportedAnnotationTypes.class);
duke@1:             if  (sat == null) {
duke@1:                 if (isInitialized())
duke@1:                     processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
duke@1:                                                              "No SupportedAnnotationTypes annotation " +
duke@1:                                                              "found on " + this.getClass().getName() +
duke@1:                                                              ", returning an empty set.");
duke@1:                 return Collections.emptySet();
duke@1:             }
duke@1:             else
duke@1:                 return arrayToSet(sat.value());
duke@1:         }
duke@1: 
duke@1:     /**
duke@1:      * If the processor class is annotated with {@link
duke@1:      * SupportedSourceVersion}, return the source version in the
duke@1:      * annotation.  If the class is not so annotated, {@link
duke@1:      * SourceVersion#RELEASE_6} is returned.
duke@1:      *
duke@1:      * @return the latest source version supported by this processor
duke@1:      */
duke@1:     public SourceVersion getSupportedSourceVersion() {
duke@1:         SupportedSourceVersion ssv = this.getClass().getAnnotation(SupportedSourceVersion.class);
duke@1:         SourceVersion sv = null;
duke@1:         if (ssv == null) {
duke@1:             sv = SourceVersion.RELEASE_6;
duke@1:             if (isInitialized())
duke@1:                 processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
duke@1:                                                          "No SupportedSourceVersion annotation " +
duke@1:                                                          "found on " + this.getClass().getName() +
duke@1:                                                          ", returning " + sv + ".");
duke@1:         } else
duke@1:             sv = ssv.value();
duke@1:         return sv;
duke@1:     }
duke@1: 
duke@1: 
duke@1:     /**
duke@1:      * Initializes the processor with the processing environment by
duke@1:      * setting the {@code processingEnv} field to the value of the
duke@1:      * {@code processingEnv} argument.  An {@code
duke@1:      * IllegalStateException} will be thrown if this method is called
duke@1:      * more than once on the same object.
duke@1:      *
duke@1:      * @param processingEnv environment to access facilities the tool framework
duke@1:      * provides to the processor
duke@1:      * @throws IllegalStateException if this method is called more than once.
duke@1:      */
duke@1:     public synchronized void init(ProcessingEnvironment processingEnv) {
duke@1:         if (initialized)
duke@1:             throw new IllegalStateException("Cannot call init more than once.");
duke@1:         if (processingEnv == null)
duke@1:             throw new NullPointerException("Tool provided null ProcessingEnvironment");
duke@1: 
duke@1:         this.processingEnv = processingEnv;
duke@1:         initialized = true;
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * {@inheritDoc}
duke@1:      */
duke@1:     public abstract boolean process(Set<? extends TypeElement> annotations,
duke@1:                                     RoundEnvironment roundEnv);
duke@1: 
duke@1:     /**
duke@1:      * Returns an empty iterable of completions.
duke@1:      *
duke@1:      * @param element {@inheritDoc}
duke@1:      * @param annotation {@inheritDoc}
duke@1:      * @param member {@inheritDoc}
duke@1:      * @param userText {@inheritDoc}
duke@1:      */
duke@1:     public Iterable<? extends Completion> getCompletions(Element element,
duke@1:                                                          AnnotationMirror annotation,
duke@1:                                                          ExecutableElement member,
duke@1:                                                          String userText) {
duke@1:         return Collections.emptyList();
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Returns {@code true} if this object has been {@linkplain #init
duke@1:      * initialized}, {@code false} otherwise.
duke@1:      *
duke@1:      * @return {@code true} if this object has been initialized,
duke@1:      * {@code false} otherwise.
duke@1:      */
duke@1:     protected synchronized boolean isInitialized() {
duke@1:         return initialized;
duke@1:     }
duke@1: 
duke@1:     private static Set<String> arrayToSet(String[] array) {
duke@1:         assert array != null;
duke@1:         Set<String> set = new HashSet<String>(array.length);
duke@1:         for (String s : array)
duke@1:             set.add(s);
duke@1:         return Collections.unmodifiableSet(set);
duke@1:     }
duke@1: }