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com.github.richygreat.springsagaevent.annotation.SagaEventHandlerBinder Maven / Gradle / Ivy
package com.github.richygreat.springsagaevent.annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import org.springframework.amqp.core.AmqpAdmin;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.TopicExchange;
import org.springframework.aop.support.AopUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ReflectionUtils;
import lombok.RequiredArgsConstructor;
@RequiredArgsConstructor
public final class SagaEventHandlerBinder {
private static final String INVALID_BINDING_METHOD_ARGS_LENGTH = "Only 1 parameter is allowed in Saga Listener methods";
private static final String INVALID_BINDING_METHOD_RET_TYPE_VOID = "Return type should not be void for SagaTransition and SagaCompensationBranchStart methods";
private final AmqpAdmin amqpSagaAdmin;
private final TopicExchange sagaEventsExchange;
private final Queue sagaEventsQueue;
private final TopicExchange sagaEventsDlxExchange;
private final Queue sagaEventsDlxQueue;
private final ApplicationContext applicationContext;
private Map> sagaEventHandlerMap = new HashMap<>();
public Map> bind() {
Map sagaEventHandlerBeanMap = applicationContext.getBeansWithAnnotation(SagaEventHandler.class);
Collection sagaEventHandlerBeans = sagaEventHandlerBeanMap.values();
if (CollectionUtils.isEmpty(sagaEventHandlerBeans)) {
return sagaEventHandlerMap;
}
bindSagaTransition(sagaEventHandlerBeans);
bindSagaEnd(sagaEventHandlerBeans);
bindSagaCompensationBranchStart(sagaEventHandlerBeans);
bindSagaSideStep(sagaEventHandlerBeans);
bindSagaCompensationEnd(sagaEventHandlerBeans);
return sagaEventHandlerMap;
}
private void bindSagaTransition(Collection beans) {
Consumer amqpBindingConsumer = new AmqpSagaEventBindingConsumer(sagaEventHandlerMap, (bean, method) -> {
SagaTransition sagaTransition = AnnotationUtils.findAnnotation(method, SagaTransition.class);
if (sagaTransition != null) {
Assert.isTrue(method.getParameterTypes().length == 1, INVALID_BINDING_METHOD_ARGS_LENGTH);
Assert.isTrue(!method.getReturnType().equals(Void.TYPE), INVALID_BINDING_METHOD_RET_TYPE_VOID);
String sagaEvent = sagaTransition.name() + "." + sagaTransition.previousEvent();
return new SagaEventHandlerType(sagaEvent, bean, method, sagaTransition);
}
return null;
}, amqpSagaAdmin, sagaEventsQueue, sagaEventsExchange, sagaEventsDlxQueue, sagaEventsDlxExchange);
beans.forEach(amqpBindingConsumer);
}
private void bindSagaEnd(Collection beans) {
Consumer amqpBindingConsumer = new AmqpSagaEventBindingConsumer(sagaEventHandlerMap, (bean, method) -> {
SagaEnd sagaEnd = AnnotationUtils.findAnnotation(method, SagaEnd.class);
if (sagaEnd != null) {
Assert.isTrue(method.getParameterTypes().length == 1, INVALID_BINDING_METHOD_ARGS_LENGTH);
String sagaEvent = sagaEnd.name() + "." + sagaEnd.previousEvent();
return new SagaEventHandlerType(sagaEvent, bean, method, sagaEnd);
}
return null;
}, amqpSagaAdmin, sagaEventsQueue, sagaEventsExchange, sagaEventsDlxQueue, sagaEventsDlxExchange);
beans.forEach(amqpBindingConsumer);
}
private void bindSagaCompensationBranchStart(Collection beans) {
Consumer amqpBindingConsumer = new AmqpSagaEventBindingConsumer(sagaEventHandlerMap, (bean, method) -> {
SagaCompensationBranchStart sagaCompensationBranchStart = AnnotationUtils.findAnnotation(method,
SagaCompensationBranchStart.class);
if (sagaCompensationBranchStart != null) {
Assert.isTrue(method.getParameterTypes().length == 1, INVALID_BINDING_METHOD_ARGS_LENGTH);
Assert.isTrue(!method.getReturnType().equals(Void.TYPE), INVALID_BINDING_METHOD_RET_TYPE_VOID);
String sagaEvent = sagaCompensationBranchStart.branchoutSagaName() + "."
+ sagaCompensationBranchStart.branchoutEvent();
return new SagaEventHandlerType(sagaEvent, bean, method, sagaCompensationBranchStart);
}
return null;
}, amqpSagaAdmin, sagaEventsQueue, sagaEventsExchange, sagaEventsDlxQueue, sagaEventsDlxExchange);
beans.forEach(amqpBindingConsumer);
}
private void bindSagaSideStep(Collection beans) {
Consumer amqpBindingConsumer = new AmqpSagaEventBindingConsumer(sagaEventHandlerMap, (bean, method) -> {
SagaSideStep sagaSideStep = AnnotationUtils.findAnnotation(method, SagaSideStep.class);
if (sagaSideStep != null) {
Assert.isTrue(method.getParameterTypes().length == 1, INVALID_BINDING_METHOD_ARGS_LENGTH);
String sagaEvent = sagaSideStep.name() + "." + sagaSideStep.previousEvent();
return new SagaEventHandlerType(sagaEvent, bean, method, sagaSideStep);
}
return null;
}, amqpSagaAdmin, sagaEventsQueue, sagaEventsExchange, sagaEventsDlxQueue, sagaEventsDlxExchange);
beans.forEach(amqpBindingConsumer);
}
private void bindSagaCompensationEnd(Collection beans) {
Consumer amqpBindingConsumer = new AmqpSagaEventBindingConsumer(sagaEventHandlerMap, (bean, method) -> {
SagaCompensationEnd sagaCompensationEnd = AnnotationUtils.findAnnotation(method, SagaCompensationEnd.class);
if (sagaCompensationEnd != null) {
Assert.isTrue(method.getParameterTypes().length == 1, INVALID_BINDING_METHOD_ARGS_LENGTH);
String sagaEvent = sagaCompensationEnd.name() + "." + sagaCompensationEnd.previousEvent();
return new SagaEventHandlerType(sagaEvent, bean, method, sagaCompensationEnd);
}
return null;
}, amqpSagaAdmin, sagaEventsQueue, sagaEventsExchange, sagaEventsDlxQueue, sagaEventsDlxExchange);
beans.forEach(amqpBindingConsumer);
}
@RequiredArgsConstructor
private static class AmqpSagaEventBindingConsumer implements Consumer {
private final Map> sagaEventHandlerMap;
private final BiFunction sagaEventHandlerConvertor;
private final AmqpAdmin amqpSagaAdmin;
private final Queue sagaEventsQueue;
private final TopicExchange sagaEventsExchange;
private final Queue sagaEventsDlxQueue;
private final TopicExchange sagaEventsDlxExchange;
@Override
public void accept(Object bean) {
Class targetClass = AopUtils.getTargetClass(bean);
ReflectionUtils.doWithMethods(targetClass, method -> {
SagaEventHandlerType type = sagaEventHandlerConvertor.apply(bean, method);
if (type != null) {
sagaEventHandlerMap.putIfAbsent(type.getSagaEvent(), new ArrayList<>());
sagaEventHandlerMap.get(type.getSagaEvent()).add(type);
amqpSagaAdmin.declareBinding(
BindingBuilder.bind(sagaEventsQueue).to(sagaEventsExchange).with(type.getSagaEvent()));
amqpSagaAdmin.declareBinding(BindingBuilder.bind(sagaEventsDlxQueue).to(sagaEventsDlxExchange)
.with(type.getSagaEvent()));
}
});
}
}
}
