Add Cluster/AllocationExplain endpoint

src/Elasticsearch/Endpoints/Cluster/AllocationExplain.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace Elasticsearch\Endpoints\Cluster;
+
+use Elasticsearch\Endpoints\AbstractEndpoint;
+
+/**
+ * Class AllocationExplain
+ *
+ * @category Elasticsearch
+ * @package  Elasticsearch\Endpoints\Cluster
+ * @author   Zachary Tong <zachary.tong@elasticsearch.com>
+ * @license  http://www.apache.org/licenses/LICENSE-2.0 Apache2
+ * @link     http://elasticsearch.org
+ */
+class AllocationExplain extends AbstractEndpoint
+{
+
+    /**
+     * @param array $body
+     *
+     * @throws \Elasticsearch\Common\Exceptions\InvalidArgumentException
+     * @return $this
+     */
+    public function setBody($body)
+    {
+        if (isset($body) !== true) {
+            return $this;
+        }
+
+        $this->body = $body;
+
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    protected function getURI()
+    {
+        return "/_cluster/allocation/explain";
+    }
+
+    /**
+     * @return string[]
+     */
+    protected function getParamWhitelist()
+    {
+        return array(
+            'include_yes_decisions'
+        );
+    }
+
+    /**
+     * @return string
+     */
+    protected function getMethod()
+    {
+        return 'GET';
+    }
+}

src/Elasticsearch/Namespaces/ClusterNamespace.php

@@ -187,4 +187,27 @@ public function pendingTasks($params = array())
 
         return $endpoint->resultOrFuture($response);
     }
+
+    /**
+     * $params['include_yes_decisions'] = (bool) Return 'YES' decisions in explanation (default: false)
+     *
+     * @param $params array Associative array of parameters
+     *
+     * @return array
+     */
+    public function allocationExplain($params = array())
+    {
+        $body = $this->extractArgument($params, 'body');
+
+        /** @var callback $endpointBuilder */
+        $endpointBuilder = $this->endpoints;
+
+        /** @var \Elasticsearch\Endpoints\Cluster\AllocationExplain $endpoint */
+        $endpoint = $endpointBuilder('Cluster\AllocationExplain');
+        $endpoint->setBody($body)
+                 ->setParams($params);
+        $response = $endpoint->performRequest();
+
+        return $endpoint->resultOrFuture($response);
+    }
 }