CLIStreamReader.java

package org.opennaas.extensions.protocols.cli;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.List;

import org.opennaas.extensions.protocols.cli.message.CLIResponseMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 * @author edu
 * 
 */
public class CLIStreamReader {

	/** Logger */
	static private Logger				logger		= LoggerFactory.getLogger(CLIStreamReader.class);

	/** The prompts used to detect the end of the message **/
	private List<String>				prompts;

	/**
	 * Contains a pair of <intermediate_prompt, string to be send>, to make the remote agent continue sending the response message
	 **/
	private Hashtable<String, String>	intermediatePrompts;

	/** Contains some of the strings that appear when the response message is an error message **/
	private List<String>				errorMessagePatterns;

	/** The stream to receive characters of the CLI response message **/
	private BufferedReader				cliStream;

	/** Int value for Carriage Return */
	public static final int				CR			= 13;

	/** Int value for Line Feed */
	public static final int				LF			= 10;

	/** Int value for valid character start */
	public static final int				VALIDSTART	= 31;

	/** Int value for valid character stop */
	public static final int				VALIDSTOP	= 127;

	/** String Buffer to input Data */
	private StringBuilder				buffer		= null;

	/** PrintWriter to write to the stream transport */
	private PrintWriter					outPrint;

	/**
	 * Creates a CLIStreamReader that will listen for the characters received in the stream, assemble response messages and parse them
	 * 
	 * @param stream
	 * @param oStream
	 * @param prompts
	 * @param intermediatePrompts
	 * @param errorMessagePatterns
	 */
	public CLIStreamReader(InputStream stream, OutputStream oStream, List<String> prompts,
			Hashtable<String, String> intermediatePrompts, List<String> errorMessagePatterns) {
		this.prompts = prompts;
		this.intermediatePrompts = intermediatePrompts;
		this.errorMessagePatterns = errorMessagePatterns;
		cliStream = new BufferedReader(new InputStreamReader(stream));
		outPrint = new PrintWriter(oStream, true);
		buffer = new StringBuilder();
	}

	/**
	 * Gets a response message from the input stream. If the request message is echoed, it will eliminate it from the response
	 * 
	 * @param request
	 * @return
	 */
	public CLIResponseMessage getResponse(String request) throws IOException {
		try {
			int c;
			String currentResponse = null;
			List<String> stringsToRemove = new ArrayList<String>();
			stringsToRemove.add(request);
			CLIResponseMessage response = null;

			boolean end = false;
			while (((c = cliStream.read()) != -1) && !end) {
				if ((c > VALIDSTART && c < VALIDSTOP) || c == LF || c == CR) {
					// Append the character to the buffer of received characters
					buffer.append((char) c);
					currentResponse = buffer.toString();

					// Check for prompts
					for (int i = 0; i < prompts.size(); i++) {
						if (currentResponse.indexOf(prompts.get(i)) != -1) {
							// Prompt detected, end of the message, parse it!
							logger.debug("Message received, let's process it: " + currentResponse);
							stringsToRemove.add(prompts.get(i));
							// process message
							response = CLIResponseMessage.parse(currentResponse, stringsToRemove, errorMessagePatterns);
							buffer = new StringBuilder();
							// quit the loops
							return response;
						}
					}

					// Check for intermediate prompts
					Enumeration<String> iterator = intermediatePrompts.keys();
					while (iterator.hasMoreElements()) {
						String currentKey = iterator.nextElement();
						if (currentResponse.endsWith(currentKey)) {
							// Intermediate prompt detected
							logger.debug("Intermediate prompt detected, sending continue character:" + intermediatePrompts.get(currentKey));
							outPrint.println(intermediatePrompts.get(currentKey).toCharArray());
							stringsToRemove.add(currentKey);
							// quit the loop
							break;
						}
					}
				}
			}

			// return the response
			return response;
		} catch (IOException e) {
			logger.debug("Connection Lost!" + e.getMessage());
			throw e;
		}
	}
}