ONOS-3605 Create thread Session input stream mechanism, adding listener for events from the device

Change-Id: Ib323487f61d9e595f7ccdc1957a92e58b7002d2a
diff --git a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSession.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSession.java
index 2f02125..bb5e996 100644
--- a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSession.java
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSession.java
@@ -16,8 +16,8 @@
 
 package org.onosproject.netconf;
 
-import java.io.IOException;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
 
 /**
  * NETCONF session object that allows NETCONF operations on top with the physical
@@ -27,28 +27,45 @@
 public interface NetconfSession {
 
     /**
+     * Executes an asynchronous RPC to the server and obtains a future to be completed.
+     *
+     * @param request the XML containing the RPC for the server.
+     * @return Server response or ERROR
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
+     */
+    CompletableFuture<String> request(String request) throws NetconfException;
+
+
+    /**
      * Retrives the requested configuration, different from get-config.
      *
      * @param request the XML containing the request to the server.
      * @return device running configuration
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    String get(String request) throws IOException;
+    String get(String request) throws NetconfException;
 
     /**
-     * Executes an RPC to the server.
+     * Executes an synchronous RPC to the server.
      *
      * @param request the XML containing the RPC for the server.
      * @return Server response or ERROR
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    String doRPC(String request) throws IOException;
+    String requestSync(String request) throws NetconfException;
 
     /**
      * Retrives the specified configuration.
      *
      * @param targetConfiguration the type of configuration to retrieve.
      * @return specified configuration.
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    String getConfig(String targetConfiguration) throws IOException;
+    String getConfig(String targetConfiguration) throws NetconfException;
 
     /**
      * Retrives part of the specivied configuration based on the filterSchema.
@@ -57,28 +74,35 @@
      * @param configurationFilterSchema XML schema to filter the configuration
      *                                  elements we are interested in
      * @return device running configuration.
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
     String getConfig(String targetConfiguration, String configurationFilterSchema)
-            throws IOException;
+            throws NetconfException;
 
     /**
      * Retrives part of the specified configuration based on the filterSchema.
      *
      * @param newConfiguration configuration to set
      * @return true if the configuration was edited correctly
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
 
-    boolean editConfig(String newConfiguration) throws IOException;
+    boolean editConfig(String newConfiguration) throws NetconfException;
 
     /**
      * Retrives part of the specified configuration based on the filterSchema.
+     *
      * @param targetConfiguration the targetConfiguration to change
-     * @param mode selected mode to change the configuration
-     * @param newConfiguration configuration to set
+     * @param mode                selected mode to change the configuration
+     * @param newConfiguration    configuration to set
      * @return true if the configuration was edited correctly
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
     boolean editConfig(String targetConfiguration, String mode, String newConfiguration)
-            throws IOException;
+            throws NetconfException;
 
     /**
      * Copies the new configuration, an Url or a complete configuration xml tree
@@ -88,39 +112,49 @@
      * @param targetConfiguration the type of configuration to retrieve.
      * @param newConfiguration    configuration to set
      * @return true if the configuration was copied correctly
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
     boolean copyConfig(String targetConfiguration, String newConfiguration)
-            throws IOException;
+            throws NetconfException;
 
     /**
      * Deletes part of the specified configuration based on the filterSchema.
      *
      * @param targetConfiguration the name of the configuration to delete
      * @return true if the configuration was copied correctly
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    boolean deleteConfig(String targetConfiguration) throws IOException;
+    boolean deleteConfig(String targetConfiguration) throws NetconfException;
 
     /**
      * Locks the candidate configuration.
      *
      * @return true if successful.
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    boolean lock() throws IOException;
+    boolean lock() throws NetconfException;
 
     /**
      * Unlocks the candidate configuration.
      *
      * @return true if successful.
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    boolean unlock() throws IOException;
+    boolean unlock() throws NetconfException;
 
     /**
      * Closes the Netconf session with the device.
      * the first time it tries gracefully, then kills it forcefully
      *
      * @return true if closed
+     * @throws NetconfException when there is a problem in the communication process on
+     * the underlying connection
      */
-    boolean close() throws IOException;
+    boolean close() throws NetconfException;
 
     /**
      * Gets the session ID of the Netconf session.
@@ -137,10 +171,24 @@
     String getServerCapabilities();
 
     /**
-     * Sets the device capabilities.
+     * Sets the ONOS side capabilities.
      *
      * @param capabilities list of capabilities the device has.
      */
     void setDeviceCapabilities(List<String> capabilities);
 
+    /**
+     * Remove a listener from the underlying stream handler implementation.
+     *
+     * @param listener event listener.
+     */
+    void addDeviceOutputListener(NetconfDeviceOutputEventListener listener);
+
+    /**
+     * Remove a listener from the underlying stream handler implementation.
+     *
+     * @param listener event listener.
+     */
+    void removeDeviceOutputListener(NetconfDeviceOutputEventListener listener);
+
 }