Http inboundGateway caching jpa result

Question

how to cache Jpa result from handler? I tried searching some similar scenarios but I cannot find how to do it in DSL. below is my sample code..

    @Bean
    public IntegrationFlow findProducts() {
       return IntegrationFlows
       .from(Http.inboundGateway("app/products")
       .requestMapping(m -> m.methods(HttpMethod.GET))
       .errorChannel("userApp.input"))
       .handle((p, h) -> productRepository.findAll())
     .get();

}

Answer 1

Your productRepository.findAll() has to be marked with the @Cacheable:

* Annotation indicating that the result of invoking a method (or all methods
 * in a class) can be cached.
 *
 * <p>Each time an advised method is invoked, caching behavior will be applied,
 * checking whether the method has been already invoked for the given arguments.
 * A sensible default simply uses the method parameters to compute the key, but
 * a SpEL expression can be provided via the {@link #key} attribute, or a custom
 * {@link org.springframework.cache.interceptor.KeyGenerator} implementation can
 * replace the default one (see {@link #keyGenerator}).
 *
 * <p>If no value is found in the cache for the computed key, the target method
 * will be invoked and the returned value stored in the associated cache. Note
 * that Java8's {@code Optional} return types are automatically handled and its
 * content is stored in the cache if present.
 *
 * <p>This annotation may be used as a <em>meta-annotation</em> to create custom
 * <em>composed annotations</em> with attribute overrides.
 *
 * @author Costin Leau
 * @author Phillip Webb
 * @author Stephane Nicoll
 * @author Sam Brannen
 * @since 3.1
 * @see CacheConfig
 */
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface Cacheable {

See more information in the reference manual:

For caching declaration, Spring’s caching abstraction provides a set of Java annotations: