[[java-rest-high-rollover-index]]
=== Rollover Index API

[[java-rest-high-rollover-request]]
==== Rollover Request

The Rollover Index API requires a `RolloverRequest` instance.
A `RolloverRequest` requires two string arguments at construction time, and
one or more conditions that determine when the index has to be rolled over:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request]
--------------------------------------------------
<1> The alias (first argument) that points to the index to rollover, and
optionally the name of the new index in case the rollover operation is performed
<2> Condition on the age of the index
<3> Condition on the number of documents in the index
<4> Condition on the size of the index

==== Optional arguments
The following arguments can optionally be provided:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-dryRun]
--------------------------------------------------
<1> Whether the rollover should be performed (default) or only simulated

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-timeout]
--------------------------------------------------
<1> Timeout to wait for the all the nodes to acknowledge the index is opened
as a `TimeValue`
<2> Timeout to wait for the all the nodes to acknowledge the index is opened
as a `String`

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-masterTimeout]
--------------------------------------------------
<1> Timeout to connect to the master node as a `TimeValue`
<2> Timeout to connect to the master node as a `String`

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-waitForActiveShards]
--------------------------------------------------
<1> The number of active shard copies to wait for before the rollover index API
returns a response, as an `int`
<2> The number of active shard copies to wait for before the rollover index API
returns a response, as an `ActiveShardCount`

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-settings]
--------------------------------------------------
<1> Add the settings to apply to the new index, which include the number of
shards to create for it

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-mapping]
--------------------------------------------------
<1> Add the mappings to associate the new index with. See <<java-rest-high-create-index-request-mappings>>
for examples on the different ways to provide mappings

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-request-alias]
--------------------------------------------------
<1> Add the aliases to associate the new index with

[[java-rest-high-rollover-sync]]
==== Synchronous Execution

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-execute]
--------------------------------------------------

[[java-rest-high-rollover-async]]
==== Asynchronous Execution

The asynchronous execution of a rollover request requires both the `RolloverRequest`
instance and an `ActionListener` instance to be passed to the asynchronous
method:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-execute-async]
--------------------------------------------------
<1> The `RolloverRequest` 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 `RolloverResponse` looks like:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-execute-listener]
--------------------------------------------------
<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

[[java-rest-high-rollover-response]]
==== Rollover Response

The returned `RolloverResponse` allows to retrieve information about the
executed operation as follows:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[rollover-response]
--------------------------------------------------
<1> Indicates whether all of the nodes have acknowledged the request
<2> Indicates whether the requisite number of shard copies were started for
each shard in the index before timing out
<3> The name of the old index, eventually rolled over
<4> The name of the new index
<5> Whether the index has been rolled over
<6> Whether the operation was performed or it was a dry run
<7> The different conditions and whether they were matched or not