doc improvement

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@9387 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/SlaveStartMethod.java

 package hudson.model;
 
 import hudson.ExtensionPoint;
-import hudson.security.SecurityRealm;
+import hudson.model.Slave.ComputerImpl;
+import hudson.remoting.Channel.Listener;
 import hudson.util.DescriptorList;
+import hudson.util.StreamTaskListener;
 
-import java.util.List;
-import java.util.ArrayList;
-import java.util.logging.Logger;
+import java.io.InputStream;
 import java.io.OutputStream;
 
-import org.apache.commons.beanutils.ConvertUtils;
-import org.apache.commons.beanutils.Converter;
-
 /**
  * Extension point to allow control over how Slaves are started.
  *
@@ -27,7 +24,19 @@ public abstract class SlaveStartMethod implements Describable<SlaveStartMethod>,
         return true;
     }
 
-    public abstract void launch(Slave.ComputerImpl computer, OutputStream launchLog);
+    /**
+     * Launches the slave agent for the given {@link Computer}.
+     *
+     * <p>
+     * If the slave agent is launched successfully, {@link ComputerImpl#setChannel(InputStream, OutputStream, OutputStream, Listener)}
+     * should be invoked in the end to notify Hudson of the established connection.
+     * The operation could also fail, in which case there's no need to make any callback notification,
+     * (except to notify the user of the failure through {@link StreamTaskListener}.)
+     *
+     * @param listener
+     *      The progress of the launch, as well as any error, should be sent to this listener.
+     */
+    public abstract void launch(Slave.ComputerImpl computer, StreamTaskListener listener);
 
     /**
      * All registered {@link SlaveStartMethod} implementations.