/*
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* Copyright (c) 2018-2028, DreamLu All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* Neither the name of the dreamlu.net developer nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* Author: DreamLu 卢春梦 (596392912@qq.com)
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*/
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package org.springblade.core.auto.service;
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import org.springblade.core.auto.common.AbstractBladeProcessor;
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import org.springblade.core.auto.common.MultiSetMap;
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import org.springblade.core.auto.common.Sets;
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import org.springblade.core.auto.common.TypeHelper;
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import javax.annotation.processing.Filer;
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import javax.annotation.processing.ProcessingEnvironment;
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import javax.annotation.processing.RoundEnvironment;
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import javax.annotation.processing.SupportedOptions;
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import javax.lang.model.element.*;
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import javax.lang.model.type.TypeMirror;
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import javax.lang.model.util.ElementFilter;
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import javax.lang.model.util.Elements;
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import javax.lang.model.util.SimpleAnnotationValueVisitor8;
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import javax.lang.model.util.Types;
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import javax.tools.FileObject;
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import javax.tools.StandardLocation;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.lang.annotation.Annotation;
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import java.util.*;
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import java.util.stream.Collectors;
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/**
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* java spi 服务自动处理器 参考：google auto
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*
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* @author L.cm
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*/
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@SupportedOptions("debug")
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public class AutoServiceProcessor extends AbstractBladeProcessor {
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/**
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* spi 服务集合，key 接口 -> value 实现列表
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*/
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private final MultiSetMap<String, String> providers = new MultiSetMap<>();
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private TypeHelper typeHelper;
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@Override
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public synchronized void init(ProcessingEnvironment env) {
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super.init(env);
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this.typeHelper = new TypeHelper(env);
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}
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@Override
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public Set<String> getSupportedAnnotationTypes() {
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return Sets.ofImmutableSet(AutoService.class.getName());
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}
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@Override
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protected boolean processImpl(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
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if (roundEnv.processingOver()) {
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generateConfigFiles();
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} else {
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processAnnotations(annotations, roundEnv);
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}
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return true;
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}
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private void processAnnotations(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
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Set<? extends Element> elements = roundEnv.getElementsAnnotatedWith(AutoService.class);
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log(annotations.toString());
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log(elements.toString());
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for (Element e : elements) {
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TypeElement providerImplementer = (TypeElement) e;
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AnnotationMirror annotationMirror = getAnnotationMirror(e, AutoService.class);
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if (annotationMirror == null) {
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continue;
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}
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Set<TypeMirror> typeMirrors = getValueFieldOfClasses(annotationMirror);
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if (typeMirrors.isEmpty()) {
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error("No service interfaces provided for element!", e, annotationMirror);
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continue;
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}
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for (TypeMirror typeMirror : typeMirrors) {
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String providerInterfaceName = typeHelper.getType(typeMirror);
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Name providerImplementerName = providerImplementer.getQualifiedName();
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log("provider interface: " + providerInterfaceName);
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log("provider implementer: " + providerImplementerName);
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if (checkImplementer(providerImplementer, typeMirror)) {
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providers.put(providerInterfaceName, typeHelper.getType(providerImplementer));
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} else {
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String message = "ServiceProviders must implement their service provider interface. "
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+ providerImplementerName + " does not implement " + providerInterfaceName;
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error(message, e, annotationMirror);
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}
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}
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}
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}
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private void generateConfigFiles() {
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Filer filer = processingEnv.getFiler();
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for (String providerInterface : providers.keySet()) {
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String resourceFile = "META-INF/services/" + providerInterface;
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log("Working on resource file: " + resourceFile);
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try {
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SortedSet<String> allServices = new TreeSet<>();
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try {
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FileObject existingFile = filer.getResource(StandardLocation.CLASS_OUTPUT, "", resourceFile);
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log("Looking for existing resource file at " + existingFile.toUri());
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Set<String> oldServices = ServicesFiles.readServiceFile(existingFile.openInputStream());
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log("Existing service entries: " + oldServices);
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allServices.addAll(oldServices);
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} catch (IOException e) {
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log("Resource file did not already exist.");
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}
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Set<String> newServices = new HashSet<>(providers.get(providerInterface));
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if (allServices.containsAll(newServices)) {
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log("No new service entries being added.");
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return;
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}
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allServices.addAll(newServices);
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log("New service file contents: " + allServices);
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FileObject fileObject = filer.createResource(StandardLocation.CLASS_OUTPUT, "", resourceFile);
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OutputStream out = fileObject.openOutputStream();
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ServicesFiles.writeServiceFile(allServices, out);
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out.close();
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log("Wrote to: " + fileObject.toUri());
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} catch (IOException e) {
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fatalError("Unable to create " + resourceFile + ", " + e);
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return;
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}
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}
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}
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/**
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* Verifies {@link java.util.spi.LocaleServiceProvider} constraints on the concrete provider class.
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* Note that these constraints are enforced at runtime via the ServiceLoader,
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* we're just checking them at compile time to be extra nice to our users.
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*/
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private boolean checkImplementer(TypeElement providerImplementer, TypeMirror providerType) {
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// TODO: We're currently only enforcing the subtype relationship
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// constraint. It would be nice to enforce them all.
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Types types = processingEnv.getTypeUtils();
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return types.isSubtype(providerImplementer.asType(), providerType);
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}
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/**
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* 读取 AutoService 上的 value 值
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*
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* @param annotationMirror AnnotationMirror
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* @return value 集合
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*/
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private Set<TypeMirror> getValueFieldOfClasses(AnnotationMirror annotationMirror) {
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return getAnnotationValue(annotationMirror, "value")
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.accept(new SimpleAnnotationValueVisitor8<Set<TypeMirror>, Void>() {
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@Override
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public Set<TypeMirror> visitType(TypeMirror typeMirror, Void v) {
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Set<TypeMirror> declaredTypeSet = new HashSet<>(1);
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declaredTypeSet.add(typeMirror);
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return Collections.unmodifiableSet(declaredTypeSet);
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}
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@Override
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public Set<TypeMirror> visitArray(
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List<? extends AnnotationValue> values, Void v) {
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return values
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.stream()
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.flatMap(value -> value.accept(this, null).stream())
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.collect(Collectors.toSet());
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}
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}, null);
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}
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/**
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* Returns a {@link ExecutableElement} and its associated {@link AnnotationValue} if such
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* an element was either declared in the usage represented by the provided
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* {@link AnnotationMirror}, or if such an element was defined with a default.
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*
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* @param annotationMirror AnnotationMirror
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* @param elementName elementName
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* @return AnnotationValue map
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* @throws IllegalArgumentException if no element is defined with the given elementName.
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*/
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public AnnotationValue getAnnotationValue(AnnotationMirror annotationMirror, String elementName) {
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Objects.requireNonNull(annotationMirror);
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Objects.requireNonNull(elementName);
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for (Map.Entry<ExecutableElement, AnnotationValue> entry : getAnnotationValuesWithDefaults(annotationMirror).entrySet()) {
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if (entry.getKey().getSimpleName().contentEquals(elementName)) {
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return entry.getValue();
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}
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}
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String name = typeHelper.getType(annotationMirror);
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throw new IllegalArgumentException(String.format("@%s does not define an element %s()", name, elementName));
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}
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/**
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* Returns the {@link AnnotationMirror}'s map of {@link AnnotationValue} indexed by {@link
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* ExecutableElement}, supplying default values from the annotation if the annotation property has
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* not been set. This is equivalent to {@link
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* Elements#getElementValuesWithDefaults(AnnotationMirror)} but can be called statically without
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* an {@link Elements} instance.
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*
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* <p>The iteration order of elements of the returned map will be the order in which the {@link
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* ExecutableElement}s are defined in {@code annotation}'s {@linkplain
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* AnnotationMirror#getAnnotationType() type}.
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*
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* @param annotation AnnotationMirror
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* @return AnnotationValue Map
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*/
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public Map<ExecutableElement, AnnotationValue> getAnnotationValuesWithDefaults(AnnotationMirror annotation) {
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Map<ExecutableElement, AnnotationValue> values = new HashMap<>(32);
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Map<? extends ExecutableElement, ? extends AnnotationValue> declaredValues = annotation.getElementValues();
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for (ExecutableElement method : ElementFilter.methodsIn(annotation.getAnnotationType().asElement().getEnclosedElements())) {
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// Must iterate and put in this order, to ensure consistency in generated code.
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if (declaredValues.containsKey(method)) {
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values.put(method, declaredValues.get(method));
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} else if (method.getDefaultValue() != null) {
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values.put(method, method.getDefaultValue());
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} else {
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String name = typeHelper.getType(method);
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throw new IllegalStateException(
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"Unset annotation value without default should never happen: " + name + '.' + method.getSimpleName() + "()");
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}
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}
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return Collections.unmodifiableMap(values);
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}
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public AnnotationMirror getAnnotationMirror(Element element, Class<? extends Annotation> annotationClass) {
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String annotationClassName = annotationClass.getCanonicalName();
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for (AnnotationMirror annotationMirror : element.getAnnotationMirrors()) {
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String name = typeHelper.getType(annotationMirror);
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if (name.contentEquals(annotationClassName)) {
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return annotationMirror;
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}
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}
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return null;
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}
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}
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