javax.annotation.processing.AbstractProcessor Maven / Gradle / Ivy
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/*
* Copyright (C) 2021 ZeoFlow SRL
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.annotation.processing;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.tools.Diagnostic;
import java.util.Collections;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
/**
* An abstract annotation processor designed to be a convenient
* superclass for most concrete annotation processors. This class
* examines annotation values to compute the {@linkplain
* #getSupportedOptions options}, {@linkplain
* #getSupportedAnnotationTypes annotation types}, and {@linkplain
* #getSupportedSourceVersion source version} supported by its
* subtypes.
*
* The getter methods may {@linkplain Messager#printMessage issue
* warnings} about noteworthy conditions using the facilities available
* after the processor has been {@linkplain #isInitialized
* initialized}.
*
*
Subclasses are free to override the implementation and
* specification of any of the methods in this class as long as the
* general {@link Processor Processor}
* contract for that method is obeyed.
*
* @author Joseph D. Darcy
* @author Scott Seligman
* @author Peter von der Ahé
* @since 1.6
*/
public abstract class AbstractProcessor implements Processor
{
/**
* Processing environment providing by the tool framework.
*/
protected ProcessingEnvironment processingEnv;
private boolean initialized = false;
/**
* Constructor for subclasses to call.
*/
protected AbstractProcessor()
{
}
private static Set arrayToSet(String[] array)
{
assert array != null;
Set set = new HashSet<>(array.length);
Collections.addAll(set, array);
return Collections.unmodifiableSet(set);
}
/**
* If the processor class is annotated with {@link
* SupportedOptions}, return an unmodifiable set with the same set
* of strings as the annotation. If the class is not so
* annotated, an empty set is returned.
*
* @return the options recognized by this processor, or an empty
* set if none
*/
public Set getSupportedOptions()
{
SupportedOptions so = this.getClass().getAnnotation(SupportedOptions.class);
if (so == null)
return Collections.emptySet();
else
return arrayToSet(so.value());
}
/**
* If the processor class is annotated with {@link
* SupportedAnnotationTypes}, return an unmodifiable set with the
* same set of strings as the annotation. If the class is not so
* annotated, an empty set is returned.
*
* @return the names of the annotation types supported by this
* processor, or an empty set if none
*/
public Set getSupportedAnnotationTypes()
{
SupportedAnnotationTypes sat = this.getClass().getAnnotation(SupportedAnnotationTypes.class);
if (sat == null)
{
if (isInitialized())
processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
"No SupportedAnnotationTypes annotation " +
"found on " + this.getClass().getName() +
", returning an empty set.");
return Collections.emptySet();
} else
return arrayToSet(sat.value());
}
/**
* If the processor class is annotated with {@link
* SupportedSourceVersion}, return the source version in the
* annotation. If the class is not so annotated, {@link
* SourceVersion#RELEASE_6} is returned.
*
* @return the latest source version supported by this processor
*/
public SourceVersion getSupportedSourceVersion()
{
SupportedSourceVersion ssv = this.getClass().getAnnotation(SupportedSourceVersion.class);
SourceVersion sv;
if (ssv == null)
{
sv = SourceVersion.RELEASE_6;
if (isInitialized())
processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
"No SupportedSourceVersion annotation " +
"found on " + this.getClass().getName() +
", returning " + sv + ".");
} else
sv = ssv.value();
return sv;
}
/**
* Initializes the processor with the processing environment by
* setting the {@code processingEnv} field to the value of the
* {@code processingEnv} argument. An {@code
* IllegalStateException} will be thrown if this method is called
* more than once on the same object.
*
* @param processingEnv environment to access facilities the tool framework
* provides to the processor
*
* @throws IllegalStateException if this method is called more than once.
*/
public synchronized void init(ProcessingEnvironment processingEnv)
{
if (initialized)
throw new IllegalStateException("Cannot call init more than once.");
Objects.requireNonNull(processingEnv, "Tool provided null ProcessingEnvironment");
this.processingEnv = processingEnv;
initialized = true;
}
/**
* {@inheritDoc}
*/
public abstract boolean process(Set annotations,
RoundEnvironment roundEnv);
/**
* Returns an empty iterable of completions.
*
* @param element {@inheritDoc}
* @param annotation {@inheritDoc}
* @param member {@inheritDoc}
* @param userText {@inheritDoc}
*/
public Iterable getCompletions(Element element,
AnnotationMirror annotation,
ExecutableElement member,
String userText)
{
return Collections.emptyList();
}
/**
* Returns {@code true} if this object has been {@linkplain #init
* initialized}, {@code false} otherwise.
*
* @return {@code true} if this object has been initialized,
* {@code false} otherwise.
*/
protected synchronized boolean isInitialized()
{
return initialized;
}
}