add Batch wrapper with BindStruct method

batchx.go

@@ -0,0 +1,49 @@
+package gocqlx
+
+import (
+	"github.com/gocql/gocql"
+)
+
+type Batch struct {
+	*gocql.Batch
+}
+
+// NewBatch creates a new batch operation using defaults defined in the cluster.
+func (s *Session) NewBatch(bt gocql.BatchType) *Batch {
+	return &Batch{
+		Batch: s.Session.NewBatch(bt),
+	}
+}
+
+// BindStruct binds query named parameters to values from arg using a mapper.
+// If value cannot be found an error is reported.
+func (b *Batch) BindStruct(qry *Queryx, arg interface{}) error {
+	args, err := qry.bindStructArgs(arg, nil)
+	if err != nil {
+		return err
+	}
+	b.Query(qry.Statement(), args...)
+	return nil
+}
+
+// ExecuteBatch executes a batch operation and returns nil if successful
+// otherwise an error describing the failure.
+func (s *Session) ExecuteBatch(batch *Batch) error {
+	return s.Session.ExecuteBatch(batch.Batch)
+}
+
+// ExecuteBatchCAS executes a batch operation and returns true if successful and
+// an iterator (to scan additional rows if more than one conditional statement)
+// was sent.
+// Further scans on the interator must also remember to include
+// the applied boolean as the first argument to *Iter.Scan
+func (s *Session) ExecuteBatchCAS(batch *Batch, dest ...interface{}) (applied bool, iter *gocql.Iter, err error) {
+	return s.Session.ExecuteBatchCAS(batch.Batch, dest...)
+}
+
+// MapExecuteBatchCAS executes a batch operation much like ExecuteBatchCAS,
+// however it accepts a map rather than a list of arguments for the initial
+// scan.
+func (s *Session) MapExecuteBatchCAS(batch *Batch, dest map[string]interface{}) (applied bool, iter *gocql.Iter, err error) {
+	return s.Session.MapExecuteBatchCAS(batch.Batch, dest)
+}