INT-1655 added support for JSch Loging for SFTP adapter, updated documentation

docs/src/reference/docbook/sftp.xml

@@ -157,4 +157,22 @@ xsi:schemaLocation="http://www.springframework.org/schema/integration/sftp
   		value that computes the <emphasis>file name</emphasis> based on its original name while also appending a suffix: '-foo'.
   	</para>
   </section>
+  
+  <section id="sftp-jsch-logging">
+  	<title>SFTP/JSCH Logging</title>
+  	<para>
+  	Since we use JSch libraries (http://www.jcraft.com/jsch/) to provide SFTP support some times you may require
+  	 more information from the JSch API itself especially if something is not working properly 
+  	 (e.g., Authentication exceptions etc.). Unfortunately JSch does not use commonly used logging facilities and instead 
+  	 relies on the custom implementation of <classname>com.jcraft.jsch.Logger</classname>  interface. 
+  	 Since Spring Integration 2.0.1 we've implemented this interface, so now all you need to do to enable 
+  	 JSch logging is to configure your logger the way you usually do. For example below is sample configuration of a 
+  	 logger using Log4J.
+  	 
+  	 <programlisting language="java"><![CDATA[log4j.category.com.jcraft.jsch=DEBUG]]></programlisting>
+
+
+  	
+  	</para>
+  </section>
 </chapter>

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/session/DefaultSftpSessionFactory.java

@@ -30,10 +30,11 @@ import com.jcraft.jsch.UserInfo;
  *
  * @author Josh Long
  * @author Mario Gray
+ * @author Oleg Zhurakousky
  * @since 2.0
  */
 public class DefaultSftpSessionFactory implements SessionFactory {
-
+	
 	private volatile String host;
 
 	private volatile int port = 22; // the default
@@ -97,6 +98,8 @@ public class DefaultSftpSessionFactory implements SessionFactory {
 	}
 
 	private com.jcraft.jsch.Session initJschSession() throws Exception { 
+		JSch.setLogger(new JschLogger());
+		
 		if (this.port <= 0) {
 			this.port = 22;
 		}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/session/JschLogger.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2002-2010 the original author or authors.
+ *
+ * Licensed 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.springframework.integration.sftp.session;
+
+import org.apache.log4j.Level;
+
+import com.jcraft.jsch.Logger;
+
+/**
+ * @author Oleg Zhurakousky
+ * @since 2.0.1
+ */
+class JschLogger implements Logger {
+	
+	private final static org.apache.log4j.Logger logger = org.apache.log4j.Logger.getLogger("com.jcraft.jsch");
+
+	public boolean isEnabled(int level) {
+		return true;
+	}
+
+	public void log(int level, String message) {
+		logger.log(Level.toLevel(level), message);
+	}
+}

spring-integration-sftp/src/test/resources/log4j.properties

@@ -4,5 +4,6 @@ log4j.appender.stdout=org.apache.log4j.ConsoleAppender
 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
 log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %t %c{2}:%L - %m%n
 
-log4j.category.org.springframework=WARN
-log4j.category.org.springframework.integration=DEBUG
+log4j.category.com.jcraft.jsch=DEBUG
+log4j.category.org.springframework.integration=WARN
+log4j.category.org.springframework.integration.sftp=DEBUG