Added new nullable Time type.

bool.go

@@ -34,10 +34,9 @@ func (b *Bool) UnmarshalJSON(data []byte) error {
 	}
 
 	if value != nil {
-		b.Valid = true
-		b.Bool = *value
+		b.SetValid(*value)
 	} else {
-		b.Valid = false
+		b.SetNil()
 	}
 
 	return nil

float64.go

@@ -34,10 +34,9 @@ func (f *Float64) UnmarshalJSON(data []byte) error {
 	}
 
 	if value != nil {
-		f.Valid = true
-		f.Float64 = *value
+		f.SetValid(*value)
 	} else {
-		f.Valid = false
+		f.SetNil()
 	}
 
 	return nil

int64.go

@@ -34,10 +34,9 @@ func (i *Int64) UnmarshalJSON(data []byte) error {
 	}
 
 	if value != nil {
-		i.Valid = true
-		i.Int64 = *value
+		i.SetValid(*value)
 	} else {
-		i.Valid = false
+		i.SetNil()
 	}
 
 	return nil

string.go

@@ -34,10 +34,9 @@ func (s *String) UnmarshalJSON(data []byte) error {
 	}
 
 	if value != nil {
-		s.Valid = true
-		s.String = *value
+		s.SetValid(*value)
 	} else {
-		s.Valid = false
+		s.SetNil()
 	}
 
 	return nil

time.go

@@ -0,0 +1,56 @@
+package null
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// Time is a nullable time.Time, that supports parsing to/from JSON.
+type Time struct {
+	time.Time
+	Valid bool
+}
+
+// NewTime returns a new nullable time.Time object.
+// This is equivalent to `null.Time{Time: t, Valid: valid}`.
+func NewTime(t time.Time, valid bool) Time {
+	return Time{Time: t, Valid: valid}
+}
+
+// MarshalJSON implements the encoding json interface.
+func (t Time) MarshalJSON() ([]byte, error) {
+	if t.Valid {
+		return json.Marshal(t.Time)
+	}
+
+	return json.Marshal(nil)
+}
+
+// UnmarshalJSON implements the encoding json interface.
+func (t *Time) UnmarshalJSON(data []byte) error {
+	var value time.Time
+
+	if err := json.Unmarshal(data, &value); err != nil {
+		return err
+	}
+
+	if !value.IsZero() {
+		t.SetValid(value)
+	} else {
+		t.SetNil()
+	}
+
+	return nil
+}
+
+// SetValid sets the value and valid to true.
+func (t *Time) SetValid(value time.Time) {
+	t.Time = value
+	t.Valid = true
+}
+
+// SetNil sets the value to default and valid to false.
+func (t *Time) SetNil() {
+	t.Time = time.Time{}
+	t.Valid = false
+}

time_test.go

@@ -0,0 +1,77 @@
+package null
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+)
+
+type testTime struct {
+	Value Time `json:"value"`
+}
+
+func TestNewTime(t *testing.T) {
+	value := NewTime(time.Now(), true)
+
+	if value.Time.Equal(time.Time{}) || !value.Valid {
+		t.Fatal("New Time must have value and be valid")
+	}
+}
+
+func TestMarshalTime(t *testing.T) {
+	now := time.Now()
+	nowStrBytes, _ := json.Marshal(now)
+	nowStr := string(nowStrBytes)
+	value := Time{Time: now, Valid: true}
+
+	if data, err := json.Marshal(value); err != nil || string(data) != nowStr {
+		t.Fatalf("Time must be marshalled to value, but was %v %v", err, string(data))
+	}
+
+	value.Valid = false
+
+	if data, err := json.Marshal(value); err != nil || string(data) != "null" {
+		t.Fatalf("Time must be marshalled to null, but was %v %v", err, string(data))
+	}
+}
+
+func TestUnmarshalTime(t *testing.T) {
+	now := time.Now()
+	nowStrBytes, _ := json.Marshal(now)
+	nowStr := string(nowStrBytes)
+	str := `{"value": `+nowStr+`}`
+	var value testTime
+
+	if err := json.Unmarshal([]byte(str), &value); err != nil {
+		t.Fatalf("Time must be unmarshalled to value, but was %v", err)
+	}
+
+	if !value.Value.Valid || !value.Value.Time.Equal(now) {
+		t.Fatalf("Unmarshalled null Time must be valid, but was %v", value.Value)
+	}
+
+	str = `{"value": null}`
+
+	if err := json.Unmarshal([]byte(str), &value); err != nil {
+		t.Fatalf("Time must be unmarshalled to null, but was %v", err)
+	}
+
+	if value.Value.Valid {
+		t.Fatal("Unmarshalled null Time must be invalid")
+	}
+}
+
+func TestGettersSettersTime(t *testing.T) {
+	value := NewTime(time.Now(), true)
+	value.SetNil()
+
+	if !value.Time.Equal(time.Time{}) || value.Valid {
+		t.Fatal("Time must be nil")
+	}
+
+	value.SetValid(time.Now())
+
+	if value.Time.Equal(time.Time{}) || !value.Valid {
+		t.Fatal("Time must be valid")
+	}
+}