elasticsearch/docs/java-rest/high-level/ml/open-job.asciidoc

[[java-rest-high-x-pack-ml-open-job]]
=== Open Job API

The Open Job API provides the ability to open {ml} jobs in the cluster.
It accepts a `OpenJobRequest` object and responds
with a `OpenJobResponse` object.

[[java-rest-high-x-pack-ml-open-job-request]]
==== Open Job Request

An `OpenJobRequest` object gets created with an existing non-null `jobId`.

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests}/MlClientDocumentationIT.java[x-pack-ml-open-job-request]
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<1> Constructing a new request referencing an existing `jobId`
<2> Optionally setting the `timeout` value for how long the
execution should wait for the job to be opened.

[[java-rest-high-x-pack-ml-open-job-execution]]
==== Execution

The request can be executed through the `MachineLearningClient` contained
in the `RestHighLevelClient` object, accessed via the `machineLearningClient()` method.

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/MlClientDocumentationIT.java[x-pack-ml-open-job-execute]
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<1> `isOpened()` from the `OpenJobResponse` indicates if the job was successfully
opened or not.

[[java-rest-high-x-pack-ml-open-job-execution-async]]
==== Asynchronous Execution

The request can also be executed asynchronously:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests}/MlClientDocumentationIT.java[x-pack-ml-open-job-execute-async]
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<1> The `OpenJobRequest` to execute and the `ActionListener` to use when
the execution completes

The method does not block and returns immediately. The passed `ActionListener` is used
to notify the caller of completion. A typical `ActionListener` for `OpenJobResponse` may
look like

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests}/MlClientDocumentationIT.java[x-pack-ml-open-job-listener]
--------------------------------------------------
<1> `onResponse` is called back when the action is completed successfully
<2> `onFailure` is called back when some unexpected error occurs