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improvements for ServerLoader support
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core/src/main/java/io/github/mmm/base/service/ServiceHelper.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,134 +1,179 @@ | ||
| /* Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0 | ||
| * http://www.apache.org/licenses/LICENSE-2.0 */ | ||
| package io.github.mmm.base.service; | ||
|
|
||
| import java.util.Collection; | ||
| import java.util.Map; | ||
| import java.util.ServiceLoader; | ||
| import java.util.function.Function; | ||
|
|
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| import io.github.mmm.base.exception.DuplicateObjectException; | ||
| import io.github.mmm.base.exception.ObjectNotFoundException; | ||
|
|
||
| /** | ||
| * Helper class for {@link ServiceLoader}. | ||
| * | ||
| * @since 1.0.0 | ||
| */ | ||
| public final class ServiceHelper { | ||
|
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| private ServiceHelper() { | ||
|
|
||
| } | ||
|
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| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @return the requested service. | ||
| */ | ||
| public static final <S> S singleton(ServiceLoader<S> serviceLoader) { | ||
|
|
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| return singleton(serviceLoader, true); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param unique - {@code true} if an exception is thrown if the service is not unique, {@code false} otherwise (allow | ||
| * overriding default). | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @return the requested service. | ||
| */ | ||
| public static final <S> S singleton(ServiceLoader<S> serviceLoader, boolean unique) { | ||
|
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| S service = null; | ||
| for (S currentService : serviceLoader) { | ||
| if (service == null) { | ||
| service = currentService; | ||
| } else { | ||
| if (unique) { | ||
| String type = serviceLoader.toString(); | ||
| throw new IllegalStateException(type); | ||
| } else if (!currentService.getClass().getName().startsWith("io.github.mmm.")) { | ||
| service = currentService; | ||
| } | ||
| } | ||
| } | ||
| if (service == null) { | ||
| String type = serviceLoader.toString(); | ||
| throw new ObjectNotFoundException(type); | ||
| } | ||
| return service; | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| */ | ||
| public static final <S> void all(ServiceLoader<S> serviceLoader, Collection<S> services) { | ||
|
|
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| all(serviceLoader, services, 1); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param min the minimum number of services required. | ||
| */ | ||
| public static final <S> void all(ServiceLoader<S> serviceLoader, Collection<S> services, int min) { | ||
|
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| int serviceCount = 0; | ||
| for (S service : serviceLoader) { | ||
| services.add(service); | ||
| serviceCount++; | ||
| } | ||
| if (serviceCount < min) { | ||
| throw new IllegalStateException("Required at least " + min + " service(s) for " + serviceLoader); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param <K> type of the {@link Map} key. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param keyFunction the {@link Function} to get the {@link Map} key from the service. | ||
| */ | ||
| public static final <S, K> void all(ServiceLoader<S> serviceLoader, Map<K, S> services, Function<S, K> keyFunction) { | ||
|
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| all(serviceLoader, services, keyFunction, 1); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param <K> type of the {@link Map} key. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param keyFunction the {@link Function} to get the {@link Map} key from the service. | ||
| * @param min the minimum number of services required. | ||
| */ | ||
| public static final <S, K> void all(ServiceLoader<S> serviceLoader, Map<K, S> services, Function<S, K> keyFunction, | ||
| int min) { | ||
|
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| int serviceCount = 0; | ||
| for (S service : serviceLoader) { | ||
| K key = keyFunction.apply(service); | ||
| S duplicate = services.put(key, service); | ||
| if (duplicate != null) { | ||
| throw new DuplicateObjectException(duplicate, key, service); | ||
| } | ||
| serviceCount++; | ||
| } | ||
| if (serviceCount < min) { | ||
| throw new IllegalStateException("Required at least " + min + " service(s) for " + serviceLoader); | ||
| } | ||
| } | ||
|
|
||
| } | ||
| /* Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0 | ||
| * http://www.apache.org/licenses/LICENSE-2.0 */ | ||
| package io.github.mmm.base.service; | ||
|
|
||
| import java.util.Collection; | ||
| import java.util.Map; | ||
| import java.util.ServiceLoader; | ||
| import java.util.function.Function; | ||
|
|
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| import org.slf4j.Logger; | ||
| import org.slf4j.LoggerFactory; | ||
|
|
||
| import io.github.mmm.base.exception.DuplicateObjectException; | ||
| import io.github.mmm.base.exception.ObjectNotFoundException; | ||
|
|
||
| /** | ||
| * Helper class for {@link ServiceLoader}. | ||
| * | ||
| * @since 1.0.0 | ||
| */ | ||
| public final class ServiceHelper { | ||
|
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| private static final Logger LOG = LoggerFactory.getLogger(ServiceHelper.class); | ||
|
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| private ServiceHelper() { | ||
|
|
||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @return the requested service. | ||
| */ | ||
| public static final <S> S singleton(ServiceLoader<S> serviceLoader) { | ||
|
|
||
| return singleton(serviceLoader, true); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param unique - {@code true} if an exception is thrown if the service is not unique, {@code false} otherwise (allow | ||
| * overriding default). | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @return the requested service. | ||
| */ | ||
| public static final <S> S singleton(ServiceLoader<S> serviceLoader, boolean unique) { | ||
|
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| S service = null; | ||
| for (S currentService : serviceLoader) { | ||
| if (service == null) { | ||
| service = currentService; | ||
| } else { | ||
| service = handleDuplicate(currentService, service, serviceLoader, unique, null); | ||
| } | ||
| } | ||
| if (service == null) { | ||
| String type = serviceLoader.toString(); | ||
| throw new ObjectNotFoundException(type); | ||
| } | ||
| return service; | ||
| } | ||
|
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| private static <S> S handleDuplicate(S current, S existing, ServiceLoader<S> serviceLoader, boolean requireUnique, | ||
| Object key) { | ||
|
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| if (existing == null) { | ||
| return current; | ||
| } else if (current == null) { | ||
| return existing; // actually invalid usage but lets be tolerant | ||
| } | ||
| String currentType = current.getClass().getName(); | ||
| String existingType = existing.getClass().getName(); | ||
| boolean currentInternal = isInternalImplementation(currentType); | ||
| boolean existingInternal = isInternalImplementation(existingType); | ||
| if (requireUnique || (currentInternal == existingInternal)) { | ||
| String duplicateKey = serviceLoader.toString(); | ||
| if (key != null) { | ||
| duplicateKey = duplicateKey + "[" + key + "]"; | ||
| } | ||
| throw new DuplicateObjectException(existingType, duplicateKey, currentType); | ||
| } | ||
| if (currentInternal) { | ||
| current = existing; | ||
| String type = currentType; | ||
| currentType = existingType; | ||
| existingType = type; | ||
| } | ||
| LOG.info("For service {} the implementation {} is overridden with {}", serviceLoader.toString(), existingType, | ||
| currentType); | ||
| return current; | ||
| } | ||
|
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| private static boolean isInternalImplementation(String className) { | ||
|
|
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| return className.startsWith("io.github.mmm."); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| */ | ||
| public static final <S> void all(ServiceLoader<S> serviceLoader, Collection<S> services) { | ||
|
|
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| all(serviceLoader, services, 1); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param min the minimum number of services required. | ||
| */ | ||
| public static final <S> void all(ServiceLoader<S> serviceLoader, Collection<S> services, int min) { | ||
|
|
||
| int serviceCount = 0; | ||
| for (S service : serviceLoader) { | ||
| services.add(service); | ||
| serviceCount++; | ||
| } | ||
| if (serviceCount < min) { | ||
| throw new IllegalStateException("Required at least " + min + " service(s) for " + serviceLoader); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param <K> type of the {@link Map} key. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param keyFunction the {@link Function} to get the {@link Map} key from the service. | ||
| */ | ||
| public static final <S, K> void all(ServiceLoader<S> serviceLoader, Map<K, S> services, Function<S, K> keyFunction) { | ||
|
|
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| all(serviceLoader, services, keyFunction, 1); | ||
| } | ||
|
|
||
| /** | ||
| * @param <S> type of the service. | ||
| * @param <K> type of the {@link Map} key. | ||
| * @param serviceLoader the {@link ServiceLoader} that has to be provided from the module declaring the service API | ||
| * and holds the {@code uses} statement in its {@code module-info}. | ||
| * @param services the {@link Collection} where to add the services from the given {@link ServiceLoader}. | ||
| * @param keyFunction the {@link Function} to get the {@link Map} key from the service. | ||
| * @param min the minimum number of services required. | ||
| */ | ||
| public static final <S, K> void all(ServiceLoader<S> serviceLoader, Map<K, S> services, Function<S, K> keyFunction, | ||
| int min) { | ||
|
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| int serviceCount = 0; | ||
| for (S service : serviceLoader) { | ||
| K key = keyFunction.apply(service); | ||
| S duplicate = services.get(key); | ||
| if (duplicate == null) { | ||
| services.put(key, service); | ||
| } else { | ||
| S resolved = handleDuplicate(service, duplicate, serviceLoader, false, key); | ||
| if (resolved == service) { | ||
| services.put(key, service); | ||
| } | ||
| } | ||
| if (duplicate != null) { | ||
| throw new DuplicateObjectException(duplicate, key, service); | ||
| } | ||
| serviceCount++; | ||
| } | ||
| if (serviceCount < min) | ||
|
|
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| { | ||
| throw new IllegalStateException("Required at least " + min + " service(s) for " + serviceLoader); | ||
| } | ||
| } | ||
|
|
||
| } |