--
:api: rollup-get-rollup-index-caps
:request: GetRollupIndexCapsRequest
:response: GetRollupIndexCapsResponse
--
[role="xpack"]
[id="{upid}-x-pack-{api}"]
=== Get Rollup Index Capabilities API

experimental::[]

The Get Rollup Index Capabilities API allows the user to determine if a concrete index or index pattern contains
stored rollup jobs and data. If it contains data stored from rollup jobs, the capabilities of those jobs
are returned. The API accepts a `GetRollupIndexCapsRequest` object as a request and returns a `GetRollupIndexCapsResponse`.

[id="{upid}-x-pack-{api}-request"]
==== Get Rollup Index Capabilities Request

A +{request}+ requires a single parameter: the target index or index pattern (e.g. `rollup-foo`):

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-request]
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[id="{upid}-x-pack-{api}-execution"]
==== Execution

The Get Rollup Index Capabilities API can be executed through a `RollupClient`
instance. Such instance can be retrieved from a `RestHighLevelClient`
using the `rollup()` method:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-execute]
--------------------------------------------------

[id="{upid}-x-pack-{api}-response"]
==== Response

The returned +{response}+ holds lists and maps of values which correspond to the capabilities
of the rollup index/index pattern (what jobs are stored in the index, their capabilities, what
aggregations are available, etc). Because multiple jobs can be stored in one index, the
response may include several jobs with different configurations.

The capabilities are essentially the same as the original job configuration, just presented in a different
manner. For example, if we had created a job with the following config:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-setup]
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The +{response}+ object would contain the same information, laid out in a slightly different manner:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-response]
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[id="{upid}-x-pack-{api}-async"]
==== Asynchronous Execution

This request can be executed asynchronously:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-execute-async]
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<1> The +{request}+ to execute and the `ActionListener` to use when
the execution completes

The asynchronous method does not block and returns immediately. Once it is
completed the `ActionListener` is called back using the `onResponse` method
if the execution successfully completed or using the `onFailure` method if
it failed.

A typical listener for +{response}+ looks like:

["source","java",subs="attributes,callouts,macros"]
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include-tagged::{doc-tests-file}[x-pack-{api}-execute-listener]
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<1> Called when the execution is successfully completed. The response is
provided as an argument
<2> Called in case of failure. The raised exception is provided as an argument
