Added hintString to FindObservable

SCALA-565

Author: rozza

driver/src/main/scala/org/mongodb/scala/FindObservable.scala

@@ -237,6 +237,20 @@ case class FindObservable[TResult](private val wrapped: FindIterable[TResult]) e
  this
  }
 
+ /**
+ * Sets the hint to apply.
+ *
+ * Note: If [[hint]] is set that will be used instead of any hint string.
+ *
+ * @param hint the name of the index which should be used for the operation
+ * @return this
+ * @since 2.8
+ */
+ def hintString(hint: String): FindObservable[TResult] = {
+ wrapped.hintString(hint)
+ this
+ }
+
  /**
  * Sets the exclusive upper bound for a specific index. A null value means no max is set.
  *

driver/src/test/scala/org/mongodb/scala/FindObservableSpec.scala

@@ -45,6 +45,8 @@ class FindObservableSpec extends FlatSpec with Matchers with MockFactory {
  val observable = FindObservable(wrapper)
 
  val filter = Document("a" -> 1)
+ val hint = Document("a" -> 1)
+ val hintString = "a_1"
  val duration = Duration(1, TimeUnit.SECONDS)
  val maxDuration = Duration(10, TimeUnit.SECONDS)
  val modifiers = Document("mod" -> 1)
@@ -66,6 +68,8 @@ class FindObservableSpec extends FlatSpec with Matchers with MockFactory {
  wrapper.expects(Symbol("collation"))(collation).once()
  wrapper.expects(Symbol("cursorType"))(CursorType.NonTailable).once()
  wrapper.expects(Symbol("filter"))(filter).once()
+ wrapper.expects(Symbol("hint"))(hint).once()
+ wrapper.expects(Symbol("hintString"))(hintString).once()
  wrapper.expects(Symbol("getBatchSize"))().once()
  wrapper.expects(Symbol("limit"))(1).once()
  wrapper.expects(Symbol("maxAwaitTime"))(maxDuration.toMillis, TimeUnit.MILLISECONDS).once()
@@ -87,6 +91,8 @@ class FindObservableSpec extends FlatSpec with Matchers with MockFactory {
  observable.collation(collation)
  observable.cursorType(CursorType.NonTailable)
  observable.filter(filter)
+ observable.hint(hint)
+ observable.hintString(hintString)
  observable.limit(1)
  observable.maxAwaitTime(maxDuration)
  observable.maxScan(10L)