使用 Apache Camel 从 Mongo DB 中删除文档

Question

My main issue might be not understanding some conventions in the Camel documents.

https://camel.apache.org/components/latest/mongodb-component.html#_delete_operations

They have a camel route commented out, and two Java objects being defined, which are not commented out. What are they trying to indicate? Where are these objects at in a project?

Anyway, I'm subscribed to a JMS queue that I have another camel route publishing to. The message is a JSON string, which I save to a Mongo DB. But what I'd like to do is remove any current documents (based on criteria) and replace it with the new message.

from("jms:topic:orderbook.raw.feed")
.log("JMS Message: ${body}")
    .choice()
        .when().jsonpath("$.[?(@.type=='partial')]")
            // Figure out how to delete the old orderbook from Mongo with a type=T1
            .to("mongodb:mongo?database=k2_dev&collection=orderbooks&operation=save");

Answer 1

Does your orderbook have an ID? If so, you can enrich the JSON with an _id field (MongoDB default representation for identifiers) whose value would be that ID. Thus you'll be "upserting" that orderbook.

Obs.: Sure the Camel docs could be better.

But if you really feel you'd have to perform a remove operation before saving an orderbook, another option would be to extract its type from the current JSON string and use it as a filter when removing. Something like:

from("jms:topic:orderbook.raw.feed")
    .log("JMS Message: ${body}")
    .filter("$.[?(@.type=='partial')]")
    .multicast().stopOnException()
        .to("direct://orderbook-removal")
        .to("direct://orderbook-save")
    .end()
;

from("direct://orderbook-removal")
    // extract type and set it as the body message. e.g. {"type":"T1"}
    .to("mongodb:mongo?database=k2_dev&collection=orderbooks&operation=remove")
;

from("direct://orderbook-save")
    .to("mongodb:mongo?database=k2_dev&collection=orderbooks&operation=save")
;

The multicast sends a copy of the message to each destination. So the content won't be affected.