Introduced filter or query detect trait, refactored constant score query

docs/Query/ConstantScore.md

+# Constant score query
+
+> More info about Constant score query is in the [official elasticsearch docs][1]
+
+Inside constant score query you can insert filter or query.
+
+Lets take an example to write a constant score query with filter inside.
+
+```JSON
+{
+    "constant_score" : {
+        "filter" : {
+            "term" : { "user" : "kimchy"}
+        },
+        "boost" : 1.2
+    }
+}
+```
+
+And now the query via DSL:
+
+```php
+$termFilter = new TermFilter("user", "kimchy");
+$constantScoreQuery = new ConstantScoreQuery($termFilter, ["boost" => 1.2]);
+
+$search = new Search();
+$search->addQuery($constantScoreQuery);
+
+$queryArray = $search->toArray();
+```
+
+To form a query with query inside is very easy, just add a query in `ConstantScoreQuery` constructor instead of filter.
+
+```JSON
+{
+    "constant_score" : {
+        "query" : {
+            "term" : { "user" : "kimchy"}
+        },
+        "boost" : 1.2
+    }
+}
+```
+
+via DSL:
+
+```php
+$termQuery = new TermQuery("user", "kimchy");
+$constantScoreQuery = new ConstantScoreQuery($termQuery, ["boost" => 1.2]);
+
+$search = new Search();
+$search->addQuery($constantScoreQuery);
+
+$queryArray = $search->toArray();
+```
+
+
+[1]: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-constant-score-query.html

src/FilterOrQueryDetectionTrait.php

+<?php
+
+/*
+ * This file is part of the ONGR package.
+ *
+ * (c) NFQ Technologies UAB <info@nfq.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace ONGR\ElasticsearchDSL;
+
+/**
+ * A trait which can detect query or filter is passed.
+ */
+trait FilterOrQueryDetectionTrait
+{
+    /**
+     * Detects a dsl type.
+     *
+     * @param BuilderInterface $object
+     * @return string
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function detectDslType(BuilderInterface $object)
+    {
+        $namespace = get_class($object);
+
+        $dslTypes = ['Filter', 'Query'];
+
+        foreach ($dslTypes as $type) {
+            $length = strlen($type);
+            $dslType = substr($namespace, -$length);
+            if ($dslType === $type) {
+                return strtolower($dslType);
+            }
+        }
+
+        throw new \InvalidArgumentException();
+    }
+}

src/Query/ConstantScoreQuery.php

@@ -12,7 +12,7 @@
 namespace ONGR\ElasticsearchDSL\Query;
 
 use ONGR\ElasticsearchDSL\BuilderInterface;
-use ONGR\ElasticsearchDSL\DslTypeAwareTrait;
+use ONGR\ElasticsearchDSL\FilterOrQueryDetectionTrait;
 use ONGR\ElasticsearchDSL\ParametersTrait;
 
 /**
@@ -21,7 +21,7 @@ use ONGR\ElasticsearchDSL\ParametersTrait;
 class ConstantScoreQuery implements BuilderInterface
 {
     use ParametersTrait;
-    use DslTypeAwareTrait;
+    use FilterOrQueryDetectionTrait;
 
     /**
      * @var BuilderInterface
@@ -36,7 +36,6 @@ class ConstantScoreQuery implements BuilderInterface
     {
         $this->query = $query;
         $this->setParameters($parameters);
-        $this->setDslType('query');
     }
 
     /**
@@ -53,7 +52,7 @@ class ConstantScoreQuery implements BuilderInterface
     public function toArray()
     {
         $query = [
-            strtolower($this->getDslType()) => [
+            $this->detectDslType($this->query) => [
                 $this->query->getType() => $this->query->toArray(),
             ],
         ];

tests/FilterOrQueryDetectionTraitTest.php

+<?php
+
+/*
+ * This file is part of the ONGR package.
+ *
+ * (c) NFQ Technologies UAB <info@nfq.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace ONGR\ElasticsearchDSL\Tests\Unit\DSL;
+
+use ONGR\ElasticsearchDSL\Aggregation\GlobalAggregation;
+use ONGR\ElasticsearchDSL\Filter\MatchAllFilter;
+use ONGR\ElasticsearchDSL\FilterOrQueryDetectionTrait;
+use ONGR\ElasticsearchDSL\Query\MatchAllQuery;
+
+/**
+ * Test for FilterOrQueryDetectionTrait.
+ */
+class FilterOrQueryDetectionTraitTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var FilterOrQueryDetectionTrait
+     */
+    private $mock;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setUp()
+    {
+        $this->mock = $this->getMockForTrait('ONGR\ElasticsearchDSL\FilterOrQueryDetectionTrait');
+    }
+
+    /**
+     * Tests if setDslType throws exception.
+     *
+     * @expectedException \InvalidArgumentException
+     */
+    public function testIfTraitDetectsNotKnowType()
+    {
+        $aggregation = new GlobalAggregation('global');
+        $this->mock->detectDslType($aggregation);
+    }
+
+    /**
+     * Tests if detectDslType detects passed query.
+     */
+    public function testIfTraitDetectsQuery()
+    {
+        $query = new MatchAllQuery();
+        $result = $this->mock->detectDslType($query);
+
+        $this->assertEquals('query', $result);
+    }
+
+    /**
+     * Tests if detectDslType detects passed filter.
+     */
+    public function testIfTraitDetectsFilter()
+    {
+        $filter = new MatchAllFilter();
+        $result = $this->mock->detectDslType($filter);
+
+        $this->assertEquals('filter', $result);
+    }
+}