Add support for filters aggregation

lib/Elastica/Aggregation/Filters.php

@@ -0,0 +1,59 @@
+<?php
+
+namespace Elastica\Aggregation;
+
+use Elastica\Filter\AbstractFilter;
+
+/**
+ * Class Filters
+ * @package Elastica\Aggregation
+ * @link http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-aggregations-bucket-filters-aggregation.html
+ */
+class Filters extends AbstractAggregation
+{
+    /**
+     * Add a filter
+     *
+     * If a name is given, it will be added as a key, otherwise considered as an anonymous filter
+     *
+     * @param  AbstractFilter $filter
+     * @param  string         $name
+     * @return Filters
+     */
+    public function addFilter(AbstractFilter $filter, $name = '')
+    {
+        if (empty($name)) {
+            $filterArray[] = $filter->toArray();
+        } else {
+            $filterArray[$name] = $filter->toArray();
+        }
+
+        return $this->addParam('filters', $filterArray);
+    }
+
+    /**
+     * @return array
+     */
+    public function toArray()
+    {
+        $array   = array();
+        $filters = $this->getParam('filters');
+
+        foreach ($filters as $filter) {
+            // Detect between anonymous filters and named ones
+            $key = key($filter);
+
+            if (is_string($key)) {
+                $array['filters']['filters'][$key] = current($filter);
+            } else {
+                $array['filters']['filters'][] = current($filter);
+            }
+        }
+
+        if ($this->_aggs) {
+            $array['aggs'] = $this->_aggs;
+        }
+
+        return $array;
+    }
+}

lib/Elastica/QueryBuilder/DSL/Aggregation.php

@@ -8,6 +8,7 @@
 use Elastica\Aggregation\DateRange;
 use Elastica\Aggregation\ExtendedStats;
 use Elastica\Aggregation\Filter as FilterAggregation;
+use Elastica\Aggregation\Filters;
 use Elastica\Aggregation\GeoDistance;
 use Elastica\Aggregation\GeohashGrid;
 use Elastica\Aggregation\GlobalAggregation;
@@ -233,10 +234,11 @@ public function filter($name, AbstractFilter $filter)
      *
      * @link http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-aggregations-bucket-filters-aggregation.html
      * @param string $name
+     * @return Filters
      */
     public function filters($name)
     {
-        throw new NotImplementedException();
+        return new Filters($name);
     }
 
     /**

test/lib/Elastica/Test/Aggregation/FiltersTest.php

@@ -0,0 +1,111 @@
+<?php
+
+namespace Elastica\Test\Aggregation;
+
+use Elastica\Aggregation\Avg;
+use Elastica\Aggregation\Filter;
+use Elastica\Aggregation\Filters;
+use Elastica\Document;
+use Elastica\Filter\Range;
+use Elastica\Filter\Term;
+use Elastica\Query;
+
+class FiltersTest extends BaseAggregationTest
+{
+    protected function setUp()
+    {
+        parent::setUp();
+        $this->_index = $this->_createIndex("filter");
+        $docs = array(
+            new Document("1", array("price" => 5, "color" => "blue")),
+            new Document("2", array("price" => 8, "color" => "blue")),
+            new Document("3", array("price" => 1, "color" => "red")),
+            new Document("4", array("price" => 3, "color" => "green")),
+        );
+        $this->_index->getType("test")->addDocuments($docs);
+        $this->_index->refresh();
+    }
+
+    public function testToArrayUsingNamedFilters()
+    {
+        $expected = array(
+            "filters" => array(
+              "filters" => array(
+                  "blue" => array(
+                      "term" => array("color" => "blue")
+                  ),
+                  "red" => array(
+                      "term" => array("color" => "red")
+                  )
+              )
+            ),
+            "aggs" => array(
+                "avg_price" => array("avg" => array("field" => "price")),
+            ),
+        );
+
+        $agg = new Filters("by_color");
+        $agg->addFilter(new Term(array('color' => 'blue')), 'blue');
+        $agg->addFilter(new Term(array('color' => 'red')), 'red');
+
+        $avg = new Avg("avg_price");
+        $avg->setField("price");
+        $agg->addAggregation($avg);
+
+        $this->assertEquals($expected, $agg->toArray());
+    }
+
+    public function testToArrayUsingAnonymousFilters()
+    {
+        $expected = array(
+            "filters" => array(
+                "filters" => array(
+                    array(
+                        "term" => array("color" => "blue")
+                    ),
+                    array(
+                        "term" => array("color" => "red")
+                    )
+                )
+            ),
+            "aggs" => array(
+                "avg_price" => array("avg" => array("field" => "price")),
+            ),
+        );
+
+        $agg = new Filters("by_color");
+        $agg->addFilter(new Term(array("color" => "blue")));
+        $agg->addFilter(new Term(array("color" => "red")));
+
+        $avg = new Avg("avg_price");
+        $avg->setField("price");
+        $agg->addAggregation($avg);
+
+        $this->assertEquals($expected, $agg->toArray());
+    }
+
+    public function testFilterAggregation()
+    {
+        $agg = new Filters("by_color");
+        $agg->addFilter(new Term(array('color' => 'blue')), 'blue');
+        $agg->addFilter(new Term(array('color' => 'red')), 'red');
+
+        $avg = new Avg("avg_price");
+        $avg->setField("price");
+        $agg->addAggregation($avg);
+
+        $query = new Query();
+        $query->addAggregation($agg);
+
+        $results = $this->_index->search($query)->getAggregation("by_color");
+
+        $resultsForBlue = $results["buckets"]["blue"];
+        $resultsForRed  = $results["buckets"]["red"];
+
+        $this->assertEquals(2, $resultsForBlue["doc_count"]);
+        $this->assertEquals(1, $resultsForRed["doc_count"]);
+
+        $this->assertEquals((5 + 8) / 2, $resultsForBlue["avg_price"]["value"]);
+        $this->assertEquals(1, $resultsForRed["avg_price"]["value"]);
+    }
+}