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package test;
import javax.annotation.Generated;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.*;
import javax.lang.model.type.TypeMirror;
import javax.tools.Diagnostic;
import javax.tools.FileObject;
import javax.tools.JavaFileObject;
import javax.tools.StandardLocation;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.*;
@SupportedSourceVersion(SourceVersion.RELEASE_7)
public final class SimpleProcessor extends AbstractProcessor {
private final Map<TypeElement, List<Item>> collectedElements = new HashMap<>();
private static String callbacksClassName(TypeElement ce) {
return ce.getSimpleName() + "Callbacks";
}
private static String capitalize(String str) {
char[] chars = str.toCharArray();
return String.valueOf(chars[0]).toUpperCase() + String.valueOf(Arrays.copyOfRange(chars, 1, chars.length));
}
private static String callbacksSubClassName(Item item) {
return "On" + capitalize(item.element.getSimpleName().toString());
}
private static String callbackName(TypeElement ce, Item item) {
return callbacksClassName(ce) + '.' + callbacksSubClassName(item);
}
private static String eventName(TypeElement ce, Item item) {
return ce.getSimpleName() + fieldName(item);
}
private static String fieldName(Item item) {
return "On" + capitalize(item.element.getSimpleName().toString()) + "Event";
}
private static String toString(VariableElement var, boolean printNames) {
final StringBuilder builder = new StringBuilder();
if (printNames) {
for (final AnnotationMirror annotation : var.getAnnotationMirrors())
builder.append(annotation).append(' ');
}
builder.append(var.asType());
if (printNames)
builder.append(' ').append(var);
return builder.toString();
}
private static void generateEmit(BufferedWriter bw, TypeElement ce, Item item) throws IOException {
bw.append(" private static void emit(").append(eventName(ce, item)).append(" event, ").append(ce.getSimpleName()).append(" emmiter");
for (final VariableElement variableElement : item.element.getParameters())
bw.append(", ").append(toString(variableElement, true));
bw.append(") {\n");
bw.append(" final Collection<").append(callbackName(ce, item)).append("> callbacksSafe = event.callbacks;\n");
bw.append(" if (callbacksSafe == null)\n");
bw.append(" return;\n");
bw.append(" for (final ").append(callbackName(ce, item)).append(" callback : new ArrayList<>(callbacksSafe))\n");
bw.append(" callback.changed(emmiter");
for (final VariableElement variableElement : item.element.getParameters())
bw.append(", ").append(variableElement.getSimpleName());
bw.append(");\n");
bw.append(" }\n");
bw.newLine();
}
private static void generateEvent(BufferedWriter bw, TypeElement ce, Item item) throws IOException {
bw.append(" public static final class ").append(eventName(ce, item)).append(" {\n");
bw.append(" private Collection<").append(callbackName(ce, item)).append("> callbacks = null;\n");
bw.append("\n");
bw.append(" ").append(eventName(ce, item)).append("() {\n");
bw.append(" }\n");
bw.append("\n");
bw.append(" public void add(").append(callbackName(ce, item)).append(" callback) {\n");
bw.append(" Collection<").append(callbackName(ce, item)).append("> callbacksSafe = callbacks;\n");
bw.append(" if (callbacksSafe == null) {\n");
bw.append(" callbacksSafe = new ArrayList<>(1);\n");
bw.append(" callbacks = callbacksSafe;\n");
bw.append(" }\n");
bw.append(" callbacksSafe.add(callback);\n");
bw.append(" }\n");
bw.append("\n");
bw.append(" public void clean() {\n");
bw.append(" callbacks = null;\n");
bw.append(" }\n");
bw.append(" }");
bw.newLine();
bw.newLine();
}
private static void generateField(BufferedWriter bw, TypeElement ce, Item item) throws IOException {
bw.append(" @SuppressWarnings(\"PublicField\")\n");
bw.append(" public final ").append(eventName(ce, item)).append(' ').append(ce.getQualifiedName()).append('.').append(fieldName(item))
.append(" = new ").append(eventName(ce, item)).append("();\n");
bw.newLine();
}
private static void generatePointcut(BufferedWriter bw, TypeElement ce, Item item) throws IOException {
bw.append(" ").append(item.description.value().name().toLowerCase()).append("(): execution(").append(item.element.getReturnType().toString()).append(' ').append(ce.getQualifiedName()).append('.')
.append(item.element.getSimpleName()).append('(');
for (final Iterator<? extends TypeParameterElement> i = item.element.getTypeParameters().iterator(); i.hasNext(); ) {
bw.append(i.next().getSimpleName());
if (i.hasNext())
bw.append(", ");
}
bw.append(")) {\n");
bw.append(" final ").append(ce.getQualifiedName()).append(" emmiter = (").append(ce.getQualifiedName()).append(") thisJoinPoint.getThis();\n");
bw.append(" emit(emmiter.").append(fieldName(item)).append(", emmiter");
final List<? extends VariableElement> parameters = item.element.getParameters();
for (int i = 0, s = parameters.size(); i < s; i++) {
final VariableElement element = parameters.get(i);
final TypeMirror type = element.asType();
bw.append(", ").append('(').append(type.toString()).append(") thisJoinPoint.getArgs()[").append(Integer.toString(i)).append(']');
}
bw.append(");\n");
bw.append(" }");
bw.newLine();
bw.newLine();
}
@Override
public Set<String> getSupportedAnnotationTypes() {
return Collections.singleton(Event.class.getName());
}
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
if (roundEnv.processingOver()) {
generateAll();
return true;
}
for (final Element elem : roundEnv.getElementsAnnotatedWith(Event.class)) {
final Event description = elem.getAnnotation(Event.class);
if (description == null)
continue;
if (elem.getKind() == ElementKind.FIELD) {
// TODO(yushkovskiy): implement this
continue;
}
if (elem.getKind() != ElementKind.METHOD)
continue;
final ExecutableElement exeElement = (ExecutableElement) elem;
final Element enclosingElement = exeElement.getEnclosingElement();
final TypeElement classElement = (TypeElement) enclosingElement;
List<Item> items = collectedElements.get(classElement);
if (items == null) {
items = new ArrayList<>();
collectedElements.put(classElement, items);
}
items.add(new Item(exeElement, description));
}
return true; // no further processing of this annotation type
}
private void generateCallbacks(TypeElement ce, List<Item> items) throws IOException {
final PackageElement packageElement = (PackageElement) ce.getEnclosingElement();
final JavaFileObject jfo = processingEnv.getFiler().createSourceFile(packageElement.getQualifiedName().toString() + '.' + callbacksClassName(ce));
try (final BufferedWriter bw = new BufferedWriter(jfo.openWriter())) {
bw.append("package ").append(packageElement.getQualifiedName()).append(";");
bw.newLine();
bw.newLine();
bw.append("/**\n").append(" * Events' callbacks for ").append(ce.getQualifiedName()).append(".\n").append(" *\n").append(" * @author ").append(SimpleProcessor.class.getCanonicalName()).append("\n").append(" */");
bw.newLine();
bw.append("public final class ").append(callbacksClassName(ce)).append(" {");
bw.newLine();
for (final Item item : items) {
bw.append(" public interface ").append(callbacksSubClassName(item)).append(" {\n");
bw.append(" void changed(").append(ce.getSimpleName()).append(" emmiter");
for (final VariableElement var : item.element.getParameters())
bw.append(", ").append(toString(var, true));
bw.append(");\n");
bw.append(" }");
bw.newLine();
bw.newLine();
}
bw.append("}");
bw.newLine();
bw.newLine();
}
}
private void generateAll() {
for (final Map.Entry<TypeElement, List<Item>> entry : collectedElements.entrySet()) {
final TypeElement classElement = entry.getKey();
final PackageElement packageElement = (PackageElement) classElement.getEnclosingElement();
try {
final FileObject jfo = processingEnv.getFiler().createResource(
StandardLocation.SOURCE_OUTPUT,
packageElement.getQualifiedName(),
classElement.getSimpleName() + "EventsAspect.aj");
try (final BufferedWriter bw = new BufferedWriter(jfo.openWriter())) {
bw.append("package ").append(packageElement.getQualifiedName()).append(";");
bw.newLine();
bw.append("import java.util.ArrayList;\n");
bw.append("import java.util.Collection;");
bw.newLine();
bw.newLine();
bw.append("/**\n").append(" * Events for ").append(classElement.getQualifiedName()).append(".\n").append(" *\n").append(" * @author ").append(SimpleProcessor.class.getCanonicalName()).append("\n").append(" */");
bw.newLine();
bw.append("@").append(Generated.class.getCanonicalName()).append("(\"").append(SimpleProcessor.class.getCanonicalName()).append("\")");
bw.newLine();
bw.append("final aspect ").append(classElement.getSimpleName()).append("EventsAspect").append(" {");
bw.newLine();
bw.newLine();
generateCallbacks(classElement, entry.getValue());
for (final Item item : entry.getValue()) {
generateEvent(bw, classElement, item);
generateEmit(bw, classElement, item);
generateField(bw, classElement, item);
generatePointcut(bw, classElement, item);
}
bw.append("}");
bw.newLine();
bw.newLine();
}
} catch (final Throwable e) {
processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, e.getMessage());
}
}
}
private static final class Item {
private final ExecutableElement element;
private final Event description;
private Item(ExecutableElement element, Event description) {
this.element = element;
this.description = description;
}
}
}
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