sijie closed pull request #2450: Added Reader.HasNext in Go client
URL: https://github.com/apache/incubator-pulsar/pull/2450
This is a PR merged from a forked repository.
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diff --git a/pulsar-client-go/pulsar/c_reader.go
b/pulsar-client-go/pulsar/c_reader.go
index 730f9b86fe..12c11034aa 100644
--- a/pulsar-client-go/pulsar/c_reader.go
+++ b/pulsar-client-go/pulsar/c_reader.go
@@ -146,6 +146,19 @@ func (r *reader) Next(ctx context.Context) (Message,
error) {
}
}
+func (r *reader) HasNext() (bool, error) {
+ value := C.int(0)
+ res := C.pulsar_reader_has_message_available(r.ptr, &value)
+
+ if res != C.pulsar_result_Ok {
+ return false, newError(res, "Failed to check if next message is
available")
+ } else if value == C.int(1) {
+ return true, nil
+ } else {
+ return false, nil
+ }
+}
+
func (r *reader) Close() error {
channel := make(chan error)
r.CloseAsync(func(err error) { channel <- err; close(channel) })
diff --git a/pulsar-client-go/pulsar/reader.go
b/pulsar-client-go/pulsar/reader.go
index f61ebd7410..7015c9ca4d 100644
--- a/pulsar-client-go/pulsar/reader.go
+++ b/pulsar-client-go/pulsar/reader.go
@@ -67,6 +67,9 @@ type Reader interface {
// Read the next message in the topic, blocking until a message is
available
Next(context.Context) (Message, error)
+ // Check if there is any message available to read from the current
position
+ HasNext() (bool, error)
+
// Close the reader and stop the broker to push more messages
Close() error
}
diff --git a/pulsar-client-go/pulsar/reader_test.go
b/pulsar-client-go/pulsar/reader_test.go
index 11d1b3620c..3b075e1d50 100644
--- a/pulsar-client-go/pulsar/reader_test.go
+++ b/pulsar-client-go/pulsar/reader_test.go
@@ -20,9 +20,9 @@
package pulsar
import (
- "testing"
- "fmt"
"context"
+ "fmt"
+ "testing"
)
func TestReaderConnectError(t *testing.T) {
@@ -80,12 +80,20 @@ func TestReader(t *testing.T) {
t.Fatal(err)
}
+ hasNext, err := reader.HasNext()
+ assertNil(t, err)
+ assertEqual(t, hasNext, true)
+
msg, err := reader.Next(ctx)
assertNil(t, err)
assertNotNil(t, msg)
assertEqual(t, string(msg.Payload()), fmt.Sprintf("hello-%d",
i))
}
+
+ hasNext, err := reader.HasNext()
+ assertNil(t, err)
+ assertEqual(t, hasNext, false)
}
func TestReaderWithInvalidConf(t *testing.T) {
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