Changed DBCollection.getStats to use the collection's default read preference, as per the server selection specification.

 JAVA-1921

Author: jyemin

driver/src/main/com/mongodb/DBCollection.java

@@ -1855,7 +1855,7 @@ public void dropIndexes(final String indexName) {
      * @mongodb.driver.manual reference/command/collStats/ collStats Command
      */
     public CommandResult getStats() {
-        return getDB().executeCommand(new BsonDocument("collStats", new BsonString(getName())));
+        return getDB().executeCommand(new BsonDocument("collStats", new BsonString(getName())), getReadPreference());
     }
 
     /**

driver/src/test/functional/com/mongodb/DBCollectionSpecification.groovy

@@ -17,10 +17,12 @@
 package com.mongodb
 
 import com.mongodb.bulk.IndexRequest
+import com.mongodb.operation.CommandReadOperation
 import com.mongodb.operation.CreateIndexesOperation
 import org.bson.BsonDocument
 import org.bson.BsonInt32
 import org.bson.BsonString
+import org.bson.codecs.BsonDocumentCodec
 import spock.lang.Specification
 
 import java.util.concurrent.TimeUnit
@@ -151,4 +153,20 @@ class DBCollectionSpecification extends Specification {
         then:
         thrown(IllegalArgumentException)
     }
+
+    def 'getStats should execute the expected command with the collection default read preference'() {
+        given:
+        def executor = new TestOperationExecutor([new BsonDocument('ok', new BsonInt32(1))]);
+        def collection = new DB(getMongoClient(), 'myDatabase', executor).getCollection('test')
+        collection.setReadPreference(ReadPreference.secondary())
+
+        when:
+        collection.getStats()
+
+        then:
+        expect executor.getReadOperation(), isTheSameAs(new CommandReadOperation('myDatabase',
+                                                                                 new BsonDocument('collStats', new BsonString('test')),
+                                                                new BsonDocumentCodec()))
+        executor.getReadPreference() == collection.getReadPreference()
+    }
 }