implementing resizable exec stream

util/src/main/java/io/kubernetes/client/Exec.java

@@ -349,7 +349,20 @@ static int parseExitCode(ApiClient client, InputStream inputStream) {
     return -1;
   }
 
-  protected static class ExecProcess extends Process {
+  // ResizableExecStream defines a getter for resize stream
+  public interface ResizableExecStream {
+    // Returns an output stream for sending resizing-windows requests
+    OutputStream getResizeStream();
+  }
+
+  // ConnectionErrorExecStream defines a getter for connection error stream
+  public interface ConnectionErrorExecStream {
+    // Returns an input stream which retrieves exec connection error from the endpoint.
+    InputStream getConnectionErrorStream();
+  }
+
+  protected static class ExecProcess extends Process
+      implements ResizableExecStream, ConnectionErrorExecStream {
     private final WebSocketStreamHandler streamHandler;
     private int statusCode = -1;
     private boolean isAlive = true;
@@ -425,6 +438,16 @@ public InputStream getErrorStream() {
       return getInputStream(2);
     }
 
+    @Override
+    public InputStream getConnectionErrorStream() {
+      return getInputStream(3);
+    }
+
+    @Override
+    public OutputStream getResizeStream() {
+      return streamHandler.getOutputStream(4);
+    }
+
     private synchronized InputStream getInputStream(int stream) {
       if (!input.containsKey(stream)) {
         input.put(stream, streamHandler.getInputStream(stream));