[[java-rest-high-split-index]]
=== Split Index API

[[java-rest-high-split-index-request]]
==== Resize Request

The Split API requires a `ResizeRequest` instance.
A `ResizeRequest` requires two string arguments:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[split-index-request]
--------------------------------------------------
<1> The target index (first argument) to split the source index (second argument) into
<2> The resize type needs to be set to `SPLIT`

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

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

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

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

[[java-rest-high-split-index-sync]]
==== Synchronous Execution

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

[[java-rest-high-split-index-async]]
==== Asynchronous Execution

The asynchronous execution of a split index request requires both the `ResizeRequest`
instance and an `ActionListener` instance to be passed to the asynchronous
method:

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

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[split-index-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-split-index-response]]
==== Split Index Response

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

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