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package javax.annotation.processing;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.HashSet;
import java.util.Collections;
import java.util.Objects;
import javax.lang.model.element.*;
import javax.lang.model.SourceVersion;
import javax.tools.Diagnostic;
/**
* 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 interfaces}, 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 javax.annotation.processing.Processor Processor}
* contract for that method is obeyed.
*
* @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() {}
/**
* 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
*/
@Override
public Set getSupportedOptions() {
SupportedOptions so = this.getClass().getAnnotation(SupportedOptions.class);
return (so == null) ?
Collections.unmodifiableSet(new HashSet<>(Arrays.asList())) :
arrayToSet(so.value(), false, "option value", "@SupportedOptions");
}
/**
* 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.
*
* If the {@linkplain ProcessingEnvironment#getSourceVersion source
* version} does not support modules, in other words if it is less
* than or equal to {@link SourceVersion#RELEASE_8 RELEASE_8},
* then any leading {@linkplain Processor#getSupportedAnnotationTypes
* module prefixes} are stripped from the names.
*
* @return the names of the annotation interfaces supported by
* this processor, or an empty set if none
*/
@Override
public Set getSupportedAnnotationTypes() {
SupportedAnnotationTypes sat = this.getClass().getAnnotation(SupportedAnnotationTypes.class);
boolean initialized = isInitialized();
if (sat == null) {
if (initialized)
processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
"No SupportedAnnotationTypes annotation " +
"found on " + this.getClass().getName() +
", returning an empty set.");
return Collections.unmodifiableSet(new HashSet<>(Arrays.asList()));
} else {
boolean stripModulePrefixes =
initialized &&
processingEnv.getSourceVersion().compareTo(SourceVersion.RELEASE_8) <= 0;
return arrayToSet(sat.value(), stripModulePrefixes,
"annotation interface", "@SupportedAnnotationTypes");
}
}
/**
* 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
*/
@Override
public SourceVersion getSupportedSourceVersion() {
SupportedSourceVersion ssv = this.getClass().getAnnotation(SupportedSourceVersion.class);
SourceVersion sv = null;
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}
*/
@Override
public abstract boolean process(Set annotations,
RoundEnvironment roundEnv);
/**
* {@return an empty iterable of completions}
*
* @param element {@inheritDoc}
* @param annotation {@inheritDoc}
* @param member {@inheritDoc}
* @param userText {@inheritDoc}
*/
@Override
public Iterable getCompletions(Element element,
AnnotationMirror annotation,
ExecutableElement member,
String userText) {
return Collections.unmodifiableList(Arrays.asList());
}
/**
* {@return {@code true} if this object has been {@linkplain #init
* initialized}, {@code false} otherwise}
*/
protected synchronized boolean isInitialized() {
return initialized;
}
private Set arrayToSet(String[] array,
boolean stripModulePrefixes,
String contentType,
String annotationName) {
assert array != null;
Set set = new HashSet<>();
for (String s : array) {
boolean stripped = false;
if (stripModulePrefixes) {
int index = s.indexOf('/');
if (index != -1) {
s = s.substring(index + 1);
stripped = true;
}
}
boolean added = set.add(s);
// Don't issue a duplicate warning when the module name is
// stripped off to avoid spurious warnings in a case like
// "foo/a.B", "bar/a.B".
if (!added && !stripped && isInitialized() ) {
processingEnv.getMessager().printMessage(Diagnostic.Kind.WARNING,
"Duplicate " + contentType +
" ``" + s + "'' for processor " +
this.getClass().getName() +
" in its " + annotationName +
"annotation.");
}
}
return Collections.unmodifiableSet(set);
}
}