Spring Interation 4 CSV file splitter

FileSplitter.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.integration.splitter.AbstractMessageSplitter;
import org.springframework.integration.transformer.MessageTransformationException;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;

public class FileSplitter extends AbstractMessageSplitter {
    private static final Logger log = LoggerFactory.getLogger(FileSplitter.class);
    
    private String commentPrefix = "#";

	public Object splitMessage(Message<?> message) {
		if(log.isDebugEnabled()) {
			log.debug(message.toString());
		}
		try {
			
			Object payload = message.getPayload();
			Assert.isInstanceOf(File.class, payload, "Expected java.io.File in the message payload"); 
			
			return new BufferedReaderFileIterator((File) payload);
		} 
		catch (IOException e) {
			String msg = "Unable to transform file: " + e.getMessage();
			log.error(msg);
			throw new MessageTransformationException(msg, e);
		}
	}
	
	public void setCommentPrefix(String commentPrefix) {
		this.commentPrefix = commentPrefix;
	}

	public class BufferedReaderFileIterator implements Iterator<String> {
		
		private File file;
		private BufferedReader bufferedReader;
		private String line;
		
		public BufferedReaderFileIterator(File file) throws IOException {
			this.file = file;
			this.bufferedReader = new BufferedReader(new FileReader(file));
			readNextLine();
		}

		@Override
		public boolean hasNext() {
			return line != null;
		}

		@Override
		public String next() {
			try {
				String res = this.line;
				readNextLine();
				return res;
			} 
			catch (IOException e) {
				log.error("Error reading file", e);
				throw new RuntimeException(e);
			}	
		}

		void readNextLine() throws IOException {
			do {
				line = bufferedReader.readLine();
			}
			while(line != null && line.trim().startsWith(commentPrefix));

			if(log.isTraceEnabled()) {
				log.trace("Read next line: {}", line);
			}
			
			if(line == null) {
				close();
			}
		}

		void close() throws IOException {
			bufferedReader.close();
			file.delete();
		}

		@Override
		public void remove() {
			throw new UnsupportedOperationException();
		}
		
	}
	
}