Revert mistake removal of getFirstMessage (#1248)

build.gradle

@@ -13,7 +13,7 @@ plugins {
     id 'signing'
 }
 
-def jarVersion = "2.20.3"
+def jarVersion = "2.20.4"
 
 def isRelease = System.getenv("BUILD_EVENT") == "release"
 def brn = System.getenv("BRANCH_REF_NAME")

src/main/java/io/nats/client/JetStreamManagement.java

@@ -271,6 +271,17 @@ public interface JetStreamManagement {
      */
     MessageInfo getLastMessage(String streamName, String subject) throws IOException, JetStreamApiException;
 
+    /**
+     * Get MessageInfo for the first message of the subject.
+     * @param streamName the name of the stream.
+     * @param subject the subject to get the first message for.
+     * @return The MessageInfo
+     * @throws IOException covers various communication issues with the NATS
+     *         server such as timeout or interruption
+     * @throws JetStreamApiException the request had an error related to the data
+     */
+    MessageInfo getFirstMessage(String streamName, String subject) throws IOException, JetStreamApiException;
+
     /**
      * Get MessageInfo for the message of the message sequence
      * is equal to or greater the requested sequence for the subject.

src/main/java/io/nats/client/StreamContext.java

@@ -163,6 +163,16 @@ public interface StreamContext {
      */
     MessageInfo getLastMessage(String subject) throws IOException, JetStreamApiException;
 
+    /**
+     * Get MessageInfo for the first message of the subject.
+     * @param subject the subject to get the first message for.
+     * @return The MessageInfo
+     * @throws IOException covers various communication issues with the NATS
+     *         server such as timeout or interruption
+     * @throws JetStreamApiException the request had an error related to the data
+     */
+    MessageInfo getFirstMessage(String subject) throws IOException, JetStreamApiException;
+
     /**
      * Get MessageInfo for the message of the message sequence
      * is equal to or greater the requested sequence for the subject.

src/main/java/io/nats/client/impl/NatsJetStreamManagement.java

@@ -281,6 +281,14 @@ public MessageInfo getLastMessage(String streamName, String subject) throws IOEx
         return _getMessage(streamName, MessageGetRequest.lastForSubject(subject));
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public MessageInfo getFirstMessage(String streamName, String subject) throws IOException, JetStreamApiException {
+        return _getMessage(streamName, MessageGetRequest.firstForSubject(subject));
+    }
+
     /**
      * {@inheritDoc}
      */

src/main/java/io/nats/client/impl/NatsStreamContext.java

@@ -147,6 +147,14 @@ public MessageInfo getLastMessage(String subject) throws IOException, JetStreamA
         return jsm.getLastMessage(streamName, subject);
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public MessageInfo getFirstMessage(String subject) throws IOException, JetStreamApiException {
+        return jsm.getFirstMessage(streamName, subject);
+    }
+
     /**
      * {@inheritDoc}
      */

src/test/java/io/nats/client/impl/JetStreamManagementTests.java

@@ -1291,6 +1291,8 @@ private void validateGetMessage(JetStreamManagement jsm, TestingStreamContainer
         assertMessageInfo(tsc, 1, 2, jsm.getNextMessage(tsc.stream, -1, tsc.subject(1)), beforeCreated);
         assertMessageInfo(tsc, 0, 1, jsm.getNextMessage(tsc.stream, 0, tsc.subject(0)), beforeCreated);
         assertMessageInfo(tsc, 1, 2, jsm.getNextMessage(tsc.stream, 0, tsc.subject(1)), beforeCreated);
+        assertMessageInfo(tsc, 0, 1, jsm.getFirstMessage(tsc.stream, tsc.subject(0)), beforeCreated);
+        assertMessageInfo(tsc, 1, 2, jsm.getFirstMessage(tsc.stream, tsc.subject(1)), beforeCreated);
 
         assertMessageInfo(tsc, 0, 1, jsm.getNextMessage(tsc.stream, 1, tsc.subject(0)), beforeCreated);
         assertMessageInfo(tsc, 1, 2, jsm.getNextMessage(tsc.stream, 1, tsc.subject(1)), beforeCreated);
@@ -1305,6 +1307,7 @@ private void validateGetMessage(JetStreamManagement jsm, TestingStreamContainer
         assertStatus(10003, assertThrows(JetStreamApiException.class, () -> jsm.getMessage(tsc.stream, 0)));
         assertStatus(10037, assertThrows(JetStreamApiException.class, () -> jsm.getMessage(tsc.stream, 9)));
         assertStatus(10037, assertThrows(JetStreamApiException.class, () -> jsm.getLastMessage(tsc.stream, "not-a-subject")));
+        assertStatus(10037, assertThrows(JetStreamApiException.class, () -> jsm.getFirstMessage(tsc.stream, "not-a-subject")));
         assertStatus(10037, assertThrows(JetStreamApiException.class, () -> jsm.getNextMessage(tsc.stream, 9, tsc.subject(0))));
         assertStatus(10037, assertThrows(JetStreamApiException.class, () -> jsm.getNextMessage(tsc.stream, 1, "not-a-subject")));
     }