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charphicharphi
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Add generation of batch provider
1 parent 8310d89 commit 5be43a3

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Lines changed: 349 additions & 5 deletions

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‎CHANGELOG.md‎

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@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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- Add backend method for backends that do not support direct reloading [#564](https://github.com/nbbrd/java-service-util/issues/564)
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- Add service retrieval by ID [#317](https://github.com/nbbrd/java-service-util/issues/317)
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- Add custom signature of batch method [#322](https://github.com/nbbrd/java-service-util/issues/322)
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- Add generation of batch provider [#161](https://github.com/nbbrd/java-service-util/issues/161)
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### Changed
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‎java-service-examples/src/main/java/nbbrd/service/examples/Providers.java‎

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@@ -0,0 +1,31 @@
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package nbbrd.service.examples;
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import nbbrd.service.ServiceProvider;
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import java.util.ServiceLoader;
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public class Providers {
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public interface FooSPI {
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}
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public interface BarSPI {
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}
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// 💡 One provider, one service
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@ServiceProvider
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public static class FooProvider implements FooSPI {
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}
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// 💡 One provider, multiple services
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@ServiceProvider(FooSPI.class)
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@ServiceProvider(BarSPI.class)
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public static class FooBarProvider implements FooSPI, BarSPI {
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}
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public static void main(String[] args) {
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// 💡 Get all providers for the services
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ServiceLoader.load(FooSPI.class).forEach(System.out::println);
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ServiceLoader.load(BarSPI.class).forEach(System.out::println);
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}
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}

‎java-service-examples/src/main/java/nbbrd/service/examples/Rule.java‎

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package nbbrd.service.examples;
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import nbbrd.service.Quantifier;
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import nbbrd.service.ServiceDefinition;
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import nbbrd.service.ServiceProvider;
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import java.util.List;
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@ServiceDefinition(quantifier = Quantifier.MULTIPLE, batchType = Rule.Batch.class)
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public interface Rule {
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interface Batch {
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List<Rule> getRules();
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}
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// 💡 Generates the batch class
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@ServiceProvider
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enum GuidingPrinciples implements Rule {
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A, B, C;
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}
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static void main(String[] args) {
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// 💡 Get the batch of rules
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RuleLoader.load().forEach(System.out::println);
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}
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}

‎java-service-processor/src/main/java/internal/nbbrd/service/definition/BatchDefinition.java‎

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@@ -32,7 +32,7 @@ class BatchDefinition {
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@lombok.NonNull
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Optional<MethodReturnKind> methodReturnKind;
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enum MethodReturnKind {
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public enum MethodReturnKind {
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/** Method returns {@code Stream<Service>}. */
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STREAM,
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/** Method returns {@code Collection<Service>}. */

‎java-service-processor/src/main/java/internal/nbbrd/service/provider/BatchMethodHelper.java‎

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package internal.nbbrd.service.provider;
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import org.jspecify.annotations.Nullable;
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import javax.lang.model.element.TypeElement;
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import javax.lang.model.type.ArrayType;
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import javax.lang.model.type.DeclaredType;
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import javax.lang.model.type.TypeKind;
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import javax.lang.model.type.TypeMirror;
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import javax.lang.model.util.Elements;
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import javax.lang.model.util.Types;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.stream.Stream;
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/**
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* Helper to resolve batch method return kinds.
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*/
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@lombok.experimental.UtilityClass
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class BatchMethodHelper {
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enum ReturnKind {
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STREAM, COLLECTION, ITERABLE, ITERATOR, ARRAY
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}
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static @Nullable ReturnKind resolve(TypeMirror returnType, TypeElement serviceType, Types types, Elements elements) {
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DeclaredType streamType = types.getDeclaredType(elements.getTypeElement(Stream.class.getCanonicalName()), serviceType.asType());
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if (types.isAssignable(returnType, streamType)) return ReturnKind.STREAM;
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DeclaredType collectionType = types.getDeclaredType(elements.getTypeElement(Collection.class.getCanonicalName()), serviceType.asType());
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if (types.isAssignable(returnType, collectionType)) return ReturnKind.COLLECTION;
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DeclaredType iterableType = types.getDeclaredType(elements.getTypeElement(Iterable.class.getCanonicalName()), serviceType.asType());
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if (types.isAssignable(returnType, iterableType)) return ReturnKind.ITERABLE;
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DeclaredType iteratorType = types.getDeclaredType(elements.getTypeElement(Iterator.class.getCanonicalName()), serviceType.asType());
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if (types.isAssignable(returnType, iteratorType)) return ReturnKind.ITERATOR;
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if (returnType.getKind() == TypeKind.ARRAY) {
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TypeMirror componentType = ((ArrayType) returnType).getComponentType();
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if (types.isAssignable(componentType, types.erasure(serviceType.asType()))) return ReturnKind.ARRAY;
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}
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return null;
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}
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}
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‎java-service-processor/src/main/java/internal/nbbrd/service/provider/BatchProviderGenerator.java‎

Whitespace-only changes.

‎java-service-processor/src/main/java/internal/nbbrd/service/provider/BatchProviderRef.java‎

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package internal.nbbrd.service.provider;
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import javax.lang.model.element.TypeElement;
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import javax.lang.model.type.TypeMirror;
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/**
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* Reference to a batch provider that needs to be generated for an enum.
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*/
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@lombok.Value
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class BatchProviderRef {
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@lombok.NonNull
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TypeElement batchType;
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@lombok.NonNull
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TypeElement enumProvider;
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@lombok.NonNull
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TypeElement service;
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@lombok.NonNull
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String batchMethodName;
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@lombok.NonNull
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TypeMirror batchMethodReturnType;
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}
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‎java-service-processor/src/main/java/internal/nbbrd/service/provider/BatchProviderRegistration.java‎

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package internal.nbbrd.service.provider;
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import javax.lang.model.element.TypeElement;
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/**
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* Registration info for a generated batch provider.
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*/
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@lombok.Value
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class BatchProviderRegistration {
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@lombok.NonNull
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TypeElement batchService;
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@lombok.NonNull
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String providerClassName;
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}
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‎java-service-processor/src/main/java/internal/nbbrd/service/provider/ServiceProviderChecker.java‎

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@@ -81,6 +81,8 @@ private boolean isValidInstantiator(Instantiator instantiator) {
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return true;
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case STATIC_METHOD:
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return instantiator.getElement().getSimpleName().contentEquals("provider");
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case ENUM_FIELD:
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return true;
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default:
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return false;
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}

‎java-service-processor/src/main/java/internal/nbbrd/service/provider/ServiceProviderGenerator.java‎

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@@ -1,15 +1,21 @@
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package internal.nbbrd.service.provider;
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import com.squareup.javapoet.*;
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import internal.nbbrd.service.Instantiator;
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import internal.nbbrd.service.ProcessorTool;
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import internal.nbbrd.service.ProcessorUtil;
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import nbbrd.service.ServiceDefinition;
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import javax.annotation.processing.ProcessingEnvironment;
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import javax.lang.model.element.ElementKind;
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import javax.lang.model.element.ExecutableElement;
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import javax.lang.model.element.Modifier;
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import javax.lang.model.element.TypeElement;
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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.Types;
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import java.io.IOException;
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import java.util.Comparator;
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import java.util.List;
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import java.util.Map;
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import java.util.*;
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import java.util.function.Supplier;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
@@ -24,7 +30,17 @@ public ServiceProviderGenerator(Supplier<ProcessingEnvironment> envSupplier) {
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}
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public void generate(List<ProviderRef> annotationRefs) throws IOException {
27-
registerClassPath(annotationRefs, new ClassPathRegistry(getEnv()));
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// Generate batch providers for enums and collect their batch service registrations
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List<BatchProviderRef> batchRefs = collectBatchProviderRefs(annotationRefs);
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List<BatchProviderRegistration> batchRegistrations = generateBatchProviders(batchRefs);
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// Filter out enum providers that have batch providers generated
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List<ProviderRef> refsToRegister = filterOutEnumsWithBatchProviders(annotationRefs, batchRefs);
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// Register in SPI files
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ClassPathRegistry classPath = new ClassPathRegistry(getEnv());
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registerClassPath(refsToRegister, classPath);
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registerBatchProviders(batchRegistrations, classPath);
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}
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private void registerClassPath(List<ProviderRef> annotationRefs, ClassPathRegistry classPath) throws IOException {
@@ -52,6 +68,129 @@ private List<ProviderRef> generateDelegates(List<ProviderRef> refs) {
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return refs;
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}
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private List<BatchProviderRef> collectBatchProviderRefs(List<ProviderRef> refs) {
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List<BatchProviderRef> result = new ArrayList<>();
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for (ProviderRef ref : refs) {
74+
if (ref.getProvider().getKind() == ElementKind.ENUM) {
75+
getBatchProviderRef(ref).ifPresent(result::add);
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}
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}
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return result;
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}
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private List<ProviderRef> filterOutEnumsWithBatchProviders(List<ProviderRef> annotationRefs, List<BatchProviderRef> batchRefs) {
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// Create a set of enum providers that have batch providers for quick lookup
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Set<TypeElement> enumsWithBatchProviders = batchRefs.stream()
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.map(BatchProviderRef::getEnumProvider)
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.collect(Collectors.toSet());
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87+
// Filter out those enum providers
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return annotationRefs.stream()
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.filter(ref -> !enumsWithBatchProviders.contains(ref.getProvider()))
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.collect(Collectors.toList());
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}
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private Optional<BatchProviderRef> getBatchProviderRef(ProviderRef ref) {
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ServiceDefinition annotation = ref.getService().getAnnotation(ServiceDefinition.class);
95+
if (annotation == null) {
96+
return Optional.empty();
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}
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TypeMirror batchType = ProcessorUtil.extractResultType(annotation::batchType);
100+
if (batchType.toString().equals(Void.class.getName())) {
101+
return Optional.empty();
102+
}
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104+
TypeElement batchTypeElement = getEnv().asTypeElement(batchType);
105+
return findBatchMethod(batchTypeElement, ref.getService())
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.map(method -> new BatchProviderRef(
107+
batchTypeElement,
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ref.getProvider(),
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ref.getService(),
110+
method.getSimpleName().toString(),
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method.getReturnType()
112+
));
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}
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115+
private Optional<ExecutableElement> findBatchMethod(TypeElement batchType, TypeElement serviceType) {
116+
Types types = getEnv().getTypeUtils();
117+
return ElementFilter.methodsIn(batchType.getEnclosedElements())
118+
.stream()
119+
.filter(method -> method.getModifiers().contains(Modifier.PUBLIC))
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.filter(method -> !method.getModifiers().contains(Modifier.STATIC))
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.filter(method -> method.getParameters().isEmpty())
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.filter(method -> isBatchReturnType(method.getReturnType(), serviceType, types))
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.findFirst();
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}
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private boolean isBatchReturnType(TypeMirror returnType, TypeElement serviceType, Types types) {
127+
return BatchMethodHelper.resolve(returnType, serviceType, types, getEnv().getElementUtils()) != null;
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}
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130+
private List<BatchProviderRegistration> generateBatchProviders(List<BatchProviderRef> batchRefs) {
131+
List<BatchProviderRegistration> result = new ArrayList<>();
132+
for (BatchProviderRef ref : batchRefs) {
133+
String providerClassName = generateBatchProvider(ref);
134+
result.add(new BatchProviderRegistration(ref.getBatchType(), providerClassName));
135+
}
136+
return result;
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}
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private String generateBatchProvider(BatchProviderRef ref) {
140+
TypeSpec batchImpl = buildBatchClass(ref);
141+
String packageName = getEnv().getElementUtils().getPackageOf(ref.getEnumProvider()).getQualifiedName().toString();
142+
JavaFile javaFile = JavaFile.builder(packageName, batchImpl).build();
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ProcessorUtil.write(getEnv(), javaFile);
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// Return the fully qualified class name
146+
return packageName.isEmpty()
147+
? ref.getEnumProvider().getSimpleName() + "BatchProvider"
148+
: packageName + "." + ref.getEnumProvider().getSimpleName() + "BatchProvider";
149+
}
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private void registerBatchProviders(List<BatchProviderRegistration> registrations, ClassPathRegistry classPath) throws IOException {
152+
for (BatchProviderRegistration registration : registrations) {
153+
List<ProviderConfigurationFileLine> oldLines = classPath.readLinesByService(registration.getBatchService());
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List<ProviderConfigurationFileLine> newLines = new ArrayList<>();
155+
newLines.add(ProviderConfigurationFileLine.ofProviderBinaryName(registration.getProviderClassName()));
156+
classPath.writeLinesByService(concat(oldLines, newLines), registration.getBatchService());
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}
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}
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160+
private TypeSpec buildBatchClass(BatchProviderRef ref) {
161+
String className = ref.getEnumProvider().getSimpleName() + "BatchProvider";
162+
ClassName enumName = ClassName.get(ref.getEnumProvider());
163+
ClassName batchName = ClassName.get(ref.getBatchType());
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165+
MethodSpec method = MethodSpec.methodBuilder(ref.getBatchMethodName())
166+
.addModifiers(Modifier.PUBLIC)
167+
.addAnnotation(Override.class)
168+
.returns(TypeName.get(ref.getBatchMethodReturnType()))
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.addStatement("return $L", buildBatchMethodBody(enumName, ref))
170+
.build();
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172+
return TypeSpec.classBuilder(className)
173+
.addModifiers(Modifier.PUBLIC, Modifier.FINAL)
174+
.addSuperinterface(batchName)
175+
.addMethod(method)
176+
.build();
177+
}
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179+
private CodeBlock buildBatchMethodBody(ClassName enumName, BatchProviderRef ref) {
180+
BatchMethodHelper.ReturnKind kind = BatchMethodHelper.resolve(
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ref.getBatchMethodReturnType(), ref.getService(),
182+
getEnv().getTypeUtils(), getEnv().getElementUtils()
183+
);
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185+
if (kind == BatchMethodHelper.ReturnKind.STREAM) {
186+
return CodeBlock.of("$T.stream($T.values())", Arrays.class, enumName);
187+
} else if (kind == BatchMethodHelper.ReturnKind.ARRAY) {
188+
return CodeBlock.of("$T.values()", enumName);
189+
} else {
190+
return CodeBlock.of("$T.asList($T.values())", Arrays.class, enumName);
191+
}
192+
}
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private static boolean isStaticMethod(Instantiator o) {
56195
return o.getKind() == Instantiator.Kind.STATIC_METHOD;
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}

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