Github user VladRodionov commented on a diff in the pull request:
https://github.com/apache/incubator-ratis/pull/4#discussion_r211684885
--- Diff:
ratis-logservice/src/main/java/org/apache/ratis/logservice/api/LogReader.java
---
@@ -0,0 +1,53 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.ratis.logservice.api;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.List;
+
+/**
+ * Synchronous client interface to read from a LogStream.
+ */
+public interface LogReader extends AutoCloseable {
+
+ /**
+ * Seeks to the position before the record at the provided {@code
offset} in the LogStream.
+ *
+ * @param offset A non-negative, offset in the LogStream
+ * @return A future for when the operation is completed.
+ */
+ void seek(long recordId) throws IOException;
+
+ /**
+ * Reads the next record from the LogStream at the current position and
advances the current position
+ * to after the record which was just returned.
+ *
+ * @return The data for the next record.
+ */
+ ByteBuffer readNext() throws IOException;
--- End diff --
readNext(ByteBuffer) - to reuse existing buffer
---
