suppress the logger's message except when embulk log level is debug

Author: civitaspo

README.md

@@ -53,3 +53,7 @@ $ embulk run -Ilib example/sample.yml
 ```
 $ ./gradlew gem  # -t to watch change of files and rebuild continuously
 ```
+
+## Note
+
+This plugin uses "org.apache.commons:commons-vfs" and the library uses the logger "org.apache.commons.logging.Log". So, this plugin suppress the logger's message except when embulk log level is debug.

src/main/java/org/embulk/output/sftp/SftpFileOutput.java

@@ -46,9 +46,10 @@ public class SftpFileOutput
 
     private StandardFileSystemManager initializeStandardFileSystemManager()
     {
-//        TODO: change logging format: org.apache.commons.logging.Log
-//        System.setProperty("org.apache.commons.logging.Log",
-//                           "org.apache.commons.logging.impl.NoOpLog");
+        if (logger.isDebugEnabled()) {
+            // TODO: change logging format: org.apache.commons.logging.Log
+            System.setProperty("org.apache.commons.logging.Log", "org.apache.commons.logging.impl.NoOpLog");
+        }
         StandardFileSystemManager manager = new StandardFileSystemManager();
         try {
             manager.init();
@@ -177,8 +178,11 @@ private void closeCurrentFile()
             logger.error(e.getMessage());
             Throwables.propagate(e);
         }
-        fileIndex++;
-        currentFile = null;
+        finally {
+            fileIndex++;
+            currentFile = null;
+            currentFileOutputStream = null;
+        }
     }
 
     private URI getSftpFileUri(String remoteFilePath)