Add MaxExpansions method in MatchPhrasePrefixQuery

Close #615

.travis.yml

@@ -12,5 +12,5 @@ services:
   - docker
 before_install:
   - sudo sysctl -w vm.max_map_count=262144
-  - docker run --rm --privileged=true -p 9200:9200 -p 9300:9300 -e "bootstrap.memory_lock=true" -e "ES_JAVA_OPTS=-Xms1g -Xmx1g" docker.elastic.co/elasticsearch/elasticsearch:5.6.0 elasticsearch -Expack.security.enabled=false -Escript.inline=true -Escript.stored=true -Escript.file=true -Enetwork.host=_local_,_site_ -Enetwork.publish_host=_local_ >& /dev/null &
+  - docker run --rm --privileged=true -p 9200:9200 -p 9300:9300 -e "bootstrap.memory_lock=true" -e "ES_JAVA_OPTS=-Xms1g -Xmx1g" docker.elastic.co/elasticsearch/elasticsearch:5.6.1 elasticsearch -Expack.security.enabled=false -Escript.inline=true -Escript.stored=true -Escript.file=true -Enetwork.host=_local_,_site_ -Enetwork.publish_host=_local_ >& /dev/null &
   - sleep 30

client.go

@@ -26,7 +26,7 @@ import (
 
 const (
 	// Version is the current version of Elastic.
-	Version = "5.0.47"
+	Version = "5.0.48"
 
 	// DefaultURL is the default endpoint of Elasticsearch on the local machine.
 	// It is used e.g. when initializing a new Client without a specific URL.

search_queries_match_phrase_prefix.go

@@ -37,6 +37,12 @@ func (q *MatchPhrasePrefixQuery) Slop(slop int) *MatchPhrasePrefixQuery {
 	return q
 }
 
+// MaxExpansions sets the number of term expansions to use.
+func (q *MatchPhrasePrefixQuery) MaxExpansions(n int) *MatchPhrasePrefixQuery {
+	q.maxExpansions = &n
+	return q
+}
+
 // Boost sets the boost to apply to this query.
 func (q *MatchPhrasePrefixQuery) Boost(boost float64) *MatchPhrasePrefixQuery {
 	q.boost = &boost

search_queries_match_phrase_prefix_test.go

@@ -10,7 +10,7 @@ import (
 )
 
 func TestMatchPhrasePrefixQuery(t *testing.T) {
-	q := NewMatchPhrasePrefixQuery("message", "this is a test").Boost(0.3)
+	q := NewMatchPhrasePrefixQuery("message", "this is a test").Boost(0.3).MaxExpansions(5)
 	src, err := q.Source()
 	if err != nil {
 		t.Fatal(err)
@@ -20,7 +20,7 @@ func TestMatchPhrasePrefixQuery(t *testing.T) {
 		t.Fatalf("marshaling to JSON failed: %v", err)
 	}
 	got := string(data)
-	expected := `{"match_phrase_prefix":{"message":{"boost":0.3,"query":"this is a test"}}}`
+	expected := `{"match_phrase_prefix":{"message":{"boost":0.3,"max_expansions":5,"query":"this is a test"}}}`
 	if got != expected {
 		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
 	}