diff --git a/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/ProtocolSession.java b/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/ProtocolSession.java
index 7b31620..3c0d288 100644
--- a/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/ProtocolSession.java
+++ b/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/ProtocolSession.java
@@ -61,6 +61,7 @@ public abstract class ProtocolSession implements Closeable {
 
     public abstract void onDownlink(DownlinkRequestMessage downlinkMsg);
 
+    @Override
     public void close() {
         close(SessionCloseReason.DESTRUCTION);
     }
diff --git a/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/SessionCloseReason.java b/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/SessionCloseReason.java
index 7c7fd58..7dc0df2 100644
--- a/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/SessionCloseReason.java
+++ b/jcpp-protocol-api/src/main/java/sanbing/jcpp/protocol/domain/SessionCloseReason.java
@@ -8,7 +8,18 @@ package sanbing.jcpp.protocol.domain;
  * @author baigod
  */
 public enum SessionCloseReason {
+    /**
+     * 自然销毁
+     */
     DESTRUCTION,
+
+    /**
+     * 失活
+     */
     INACTIVE,
+
+    /**
+     * 手动销毁
+     */
     MANUALLY
 }
\ No newline at end of file