This article is part of a blog series that explores the newly redesigned Spring Cloud Stream applications based on Java Functions. In this episode, we are investigating the Aggregator function and its relationship with the Splitter function. We will see how we can customize the default behavior. We will also take a look at the importance of configuring a shared message store for the aggregator.

Here are all the previous parts of this blog series.

• Introducing Function Based Streaming Applications

• Function Composition with Streaming Applications

• How to Build a Supplier and Source Application

• How to Build a Consumer and Sink Application

• Build and Run a Simple Stream Application

• Case Study: HTTP Request Function and Processor

• Case Study: File Source and MongoDB Sink

• Case Study: Relational Database Source and File Sink

• Case Study: Remote File Ingest with Spring Cloud Data Flow

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Hi, Spring fans! In this installment Josh Long (@starbuxman) talks to Optic (@UseOptic) CEO Aidan Cunniffe (@aidandcunniffe) about OpenAPI, contract testing, and so much more

Get the Spring

Hi Spring fans! Welcome to another installment of This Week in Spring! How're things? It's been unseasonably warm here in San Francisco so I am writing this from my balcony with a warm cup of coffee and hope in my heart. It is still very hard to believe we're near Halloween, though! Crazy how time flies. There's lots of good stuff to look at this week so let's get to it! Hopefully you can enjoy this week's news from some warm, safe and healthy spot in your life, too.

• A Bootiful Podcast: DataStax's Patrick McFadin on DataStax Astra, Cassandra, Cassandra data modeling patterns, and more
• A tutorial on Batch and REST
• History of Open Source and Free Software: Dirk & Swap: Conversations on Open Source
• Incubator support for Spring and GraphQL
• Premiering: Bootiful Kotlin
• Proposed schedule for JDK 16
• Spring Authorization Server 0.0.2 available now
• Spring Boot 2.4.0-M4 available now
• Spring Data 2020.0 RC2 out now
• Spring Integration 5.4 Release Candidate 1 Available
• Spring Security: Delegating authorization checks to bean methods
• …

On behalf of the team and everyone that contributed, I am pleased to announce that the fourth milestone of Spring Boot 2.4 has been released and is available from our milestone repository.

This release closes 145 issues and pull requests. Thanks to all those who have contributed with issue reports and pull requests.

Highlights of this milestone include:

• Failure Analyzer improvements
• Ability to publish Docker images generated by the Maven and Gradle plugins
• Redis cache metrics exposed via Micrometer
• Numerous dependency upgrades

For a complete list of changes and upgrade instructions, please see the Spring Boot 2.4 Release Notes on the wiki and the updated reference documentation…

Hi, Spring fans! In this episode Josh Long (@starbuxman) talks about all the wonderful shows he's been at, the epic new support for Kubernetes-ready native images in Spring Boot 2.3 and Spring Boot 2.4, and then he talks to DataStax's own Patrick McFadin (@PatrickMcFadin), a legend in the JVM and Cassandra communities, and an all around amiable gent.

On behalf of the team and everyone who has contributed, it is my pleasure to announce the general availability of Spring Authorization Server 0.0.2.

You can download it from repo.spring.io and Maven Central by using the module coordinates:

compile 'org.springframework.security.experimental:spring-security-oauth2-authorization-server:0.0.2'

For additional details on this new project, see the initial announcement and project page.

The main features delivered in this release are:

• Proof Key for Code Exchange by OAuth Public Clients (PKCE) — RFC 7636

• User Consent page for OAuth 2.0 Authorization Code Grant — RFC 6749

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Hi, Spring fans! In this talk Spring Developer Advocate, Java Champion, and Kotlin Google Developer Advocate Josh Long (@starbuxman) introduces the Kotlin ecosystem, the language, and its application when building server-side Spring applications.

This is a roving tour of all things Kotlin, and there's a lot to cover, including:

• building Android applications with Kotlin on mobile devices
• building native applications with Kotlin and Kotlin Native ((m)alloc, pointers, and POSIX APIs, oh, my!)
• giving existing APIs like the venerable JdbcTemplate a fresh coat of paint with Kotlin
• using Kotlin ecosystem libraries like the Exposed ORM with Spring
• using rich DSLs such as those provided for Spring Framework's programmatic bean registration, HTTP endpoints, and for Spring Cloud Gateway
• kicking up our reactive applications a notch with coroutines
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Dear Spring community,

it’s my pleasure to announce the first (and the last) release candidate for Spring Integration 5.4 generation.

It can be downloaded from our milestone repository:

compile 'org.springframework.integration:spring-integration-core:5.4.0-RC1'

Since the previous milestone 3 this release brings more into bug fixes and some internal improvements according Project Reactor changes with processors.

The most notable features in this release are:

• The LogAccessor abstraction from Spring Framework is now used internally for better code readability;

• The ZeroMqMessageHandler and ZeroMqMessageProducer components are now available for one-way interaction with ZeroMq;

• The ReactiveRedisStreamMessageProducer now provides an error handling logic via sending an ErrorMessage to the errorChannel;

• The AbstractMailReceiver now has an option to not fetch a MimeMessage content eagerly and lets the downstream flow to decide what and how to do with such a mail message.

…

Dear Spring community,

On behalf of the Spring Data team and everyone who contributed, it’s my pleasure to announce that Spring Data 2020.0.0 RC2 is available from the milestone repository. This release ships with 87 tickets fixed. The most notable changes are:

• PagingAndSortingRepository support for Apache Geode.
• Support for the REVERSERANGEBYLEX command and the KEEPTTL and JUSTID flags in Redis.
• Additional MongoDB aggregation pipeline operators:$unionWith, $function, and $accumulator.
• Cyclic data loading strategy improvements in Neo4j.
• A dedicated Cassandra DataClass row mapper.
• Suspendible repository query methods for use with Kotlin.
…