/* * Copyright 2017-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.cloud.stream.binder.kafka.streams; import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; import org.apache.kafka.streams.kstream.KStream; import org.springframework.aop.framework.ProxyFactory; import org.springframework.cloud.stream.binder.ConsumerProperties; import org.springframework.cloud.stream.binder.ProducerProperties; import org.springframework.cloud.stream.binding.AbstractBindingTargetFactory; import org.springframework.cloud.stream.config.BindingProperties; import org.springframework.cloud.stream.config.BindingServiceProperties; import org.springframework.util.Assert; /** * {@link org.springframework.cloud.stream.binding.BindingTargetFactory} * for{@link KStream}. * * The implementation creates proxies for both input and output binding. The actual target * will be created downstream through further binding process. * * @author Marius Bogoevici * @author Soby Chacko */ class KStreamBoundElementFactory extends AbstractBindingTargetFactory<KStream> { private final BindingServiceProperties bindingServiceProperties; private final KafkaStreamsBindingInformationCatalogue kafkaStreamsBindingInformationCatalogue; private final EncodingDecodingBindAdviceHandler encodingDecodingBindAdviceHandler; KStreamBoundElementFactory(BindingServiceProperties bindingServiceProperties, KafkaStreamsBindingInformationCatalogue KafkaStreamsBindingInformationCatalogue, EncodingDecodingBindAdviceHandler encodingDecodingBindAdviceHandler) { super(KStream.class); this.bindingServiceProperties = bindingServiceProperties; this.kafkaStreamsBindingInformationCatalogue = KafkaStreamsBindingInformationCatalogue; this.encodingDecodingBindAdviceHandler = encodingDecodingBindAdviceHandler; } @Override public KStream createInput(String name) { BindingProperties bindingProperties = this.bindingServiceProperties.getBindingProperties(name); ConsumerProperties consumerProperties = bindingProperties.getConsumer(); if (consumerProperties == null) { consumerProperties = this.bindingServiceProperties.getConsumerProperties(name); consumerProperties.setUseNativeDecoding(true); } else { if (!encodingDecodingBindAdviceHandler.isDecodingSettingProvided()) { consumerProperties.setUseNativeDecoding(true); } } // Always set multiplex to true in the kafka streams binder consumerProperties.setMultiplex(true); return createProxyForKStream(name); } @Override @SuppressWarnings("unchecked") public KStream createOutput(final String name) { BindingProperties bindingProperties = this.bindingServiceProperties.getBindingProperties(name); ProducerProperties producerProperties = bindingProperties.getProducer(); if (producerProperties == null) { producerProperties = this.bindingServiceProperties.getProducerProperties(name); producerProperties.setUseNativeEncoding(true); } else { if (!encodingDecodingBindAdviceHandler.isEncodingSettingProvided()) { producerProperties.setUseNativeEncoding(true); } } return createProxyForKStream(name); } private KStream createProxyForKStream(String name) { KStreamWrapperHandler wrapper = new KStreamWrapperHandler(); ProxyFactory proxyFactory = new ProxyFactory(KStreamWrapper.class, KStream.class); proxyFactory.addAdvice(wrapper); KStream proxy = (KStream) proxyFactory.getProxy(); // Add the binding properties to the catalogue for later retrieval during further // binding steps downstream. BindingProperties bindingProperties = this.bindingServiceProperties .getBindingProperties(name); this.kafkaStreamsBindingInformationCatalogue.registerBindingProperties(proxy, bindingProperties); return proxy; } /** * Wrapper object for KStream proxy. */ public interface KStreamWrapper { void wrap(KStream<Object, Object> delegate); } static class KStreamWrapperHandler implements KStreamWrapper, MethodInterceptor { private KStream<Object, Object> delegate; public void wrap(KStream<Object, Object> delegate) { Assert.notNull(delegate, "delegate cannot be null"); if (this.delegate == null) { this.delegate = delegate; } } @Override public Object invoke(MethodInvocation methodInvocation) throws Throwable { if (methodInvocation.getMethod().getDeclaringClass().equals(KStream.class)) { Assert.notNull(this.delegate, "Trying to prepareConsumerBinding " + methodInvocation.getMethod() + " but no delegate has been set."); return methodInvocation.getMethod().invoke(this.delegate, methodInvocation.getArguments()); } else if (methodInvocation.getMethod().getDeclaringClass() .equals(KStreamWrapper.class)) { return methodInvocation.getMethod().invoke(this, methodInvocation.getArguments()); } else { throw new IllegalStateException( "Only KStream method invocations are permitted"); } } KStream<Object, Object> getDelegate() { return delegate; } } }