Shulou(Shulou.com)06/03 Report--

In this issue, the editor will bring you about what is published and subscribed. The article is rich in content and analyzed and described from a professional point of view. I hope you can get something after reading this article.

In software architecture, publish subscription is a message paradigm, the sender of the message will not send the message directly to a specific recipient, but will divide the published message into different categories, without knowing which subscribers may exist. Similarly, subscribers can express interest in one or more categories and receive only messages of interest without knowing which publishers exist.

In software architecture, publish subscription is a message paradigm, and the sender (called publisher) of the message does not send the message directly to a specific receiver (called subscriber). Instead, you divide the published messages into different categories, without knowing which subscribers, if any, may exist. Similarly, subscribers can express interest in one or more categories and receive only messages of interest without knowing which publishers, if any, exist.

Publish / subscribe is the sibling of the message queuing paradigm and is usually part of a larger message-oriented middleware system. Most messaging systems support both the message queuing model and the publish / subscribe model in API, such as Java message Service (JMS).

This model not only provides greater network scalability and more dynamic network topology, but also reduces the flexibility to modify the structure of publishers and published data.

Message filtering

In the publish / subscribe model, subscribers typically receive a subset of all published messages. The process of selecting messages to be received and processed is called filtering. There are two common forms of filtering: topic-based and content-based.

In a topic-based system, messages are published to topics or named channels. Subscribers will receive all messages on the topic they subscribe to, and all subscribers who subscribe to the same topic will receive the same message. The publisher is responsible for defining the categories of messages that subscribers subscribe to.

In a content-based system, a subscriber defines the conditions of the message they are interested in, and the message is delivered to the subscriber only if the property or content of the message meets the conditions defined by the subscriber. Subscribers are responsible for classifying messages.

Some systems support a mix of the two: publishers publish messages to topics, while subscribers register content-based subscriptions on one or more topics.

The above is what the editor shares with you about publishing and subscribing. If you happen to have similar doubts, please refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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