Error: "No matching method getItem found taking 1 args for class com.amazonaws.services.dax.AmazonDaxClient"

Question

I'm facing an issue while working with the com.amazonaws.services.dax.AmazonDaxClient class in my Clojure code. The error message I'm receiving is:

No matching method getItem found taking 1 args for class com.amazonaws.services.dax.AmazonDaxClient

Here is my Clojure code snippet:

(ns problem
  (:import (com.amazonaws.client.builder AwsClientBuilder$EndpointConfiguration)
           (com.amazonaws.services.dax AmazonDaxClientBuilder)
           (com.amazonaws.services.dynamodbv2.model GetItemRequest)))

(let [dax-client-builder (-> (AmazonDaxClientBuilder/standard)
                             (.withEndpointConfiguration (AwsClientBuilder$EndpointConfiguration. "dax://some.dax-clusters.eu-west-1.amazonaws.com"
                                                                                                  "eu-west-1")))
      dax-client         (.build dax-client-builder)]
  ; How can I convert dax-client to an AmazonDynamoDB instance?
  (.getItem dax-client
            (GetItemRequest.)))

I have successfully created an instance of AmazonDaxClient using AmazonDaxClientBuilder, but I need to convert it to an AmazonDynamoDB instance in order to use the getItem method that expect an AmazonDynamoDB object.

Any help or guidance on how to convert the dax-client instance to an AmazonDynamoDB instance would be greatly appreciated. Thank you.

Answer 1

If you have a look at the docs for AmazonDaxClientBuilder, you will see that the type it builds is AmazonDax. If you are sure that the type will be AmazonDaxClient, and not one of the other implementations, you can provide a type hint:

(ns problem
  (:import (com.amazonaws.client.builder AwsClientBuilder$EndpointConfiguration)
           (com.amazonaws.services.dax AmazonDaxClient AmazonDaxClientBuilder)
           (com.amazonaws.services.dynamodbv2.model GetItemRequest)))

(let [dax-client-builder (-> (AmazonDaxClientBuilder/standard)
                             (.withEndpointConfiguration (AwsClientBuilder$EndpointConfiguration. "dax://some.dax-clusters.eu-west-1.amazonaws.com"
                                                                                                  "eu-west-1")))
      dax-client         (.build dax-client-builder)]
  ; How can I convert dax-client to an AmazonDynamoDB instance?
  (.getItem ^AmazonDaxClient dax-client
            (GetItemRequest.)))

The type hint could be placed before the function call, if you will be calling more of the methods of the AmazonDaxClient object. You could of course test the type with instance?, just to be sure.