source: trunk/JavaHelperLib/src/de/ugoe/cs/util/console/TextConsole.java

package de.ugoe.cs.util.console;

import java.io.IOException;
import java.nio.charset.Charset;

import de.ugoe.cs.util.console.listener.IErrorListener;
import de.ugoe.cs.util.console.listener.IExceptionListener;
import de.ugoe.cs.util.console.listener.IOutputListener;
import de.ugoe.cs.util.console.listener.ITraceListener;

/**
 * <p>
 * Implements a simple console observer that prints normal text to
 * {@code stdout}, errors to {@code stderr} and reads from {@code stdin}.
 * </p>
 * 
 * @author Steffen Herbold
 * @version 1.0
 */
public class TextConsole implements IOutputListener, IErrorListener,
                ITraceListener, IExceptionListener {

        /**
         * <p>
         * In the debug mode, trace messages will be printed.
         * </p>
         */
        private boolean debugMode = true;

        /**
         * <p>
         * Creates a new text console and automatically registers it as observer.
         * </p>
         */
        public TextConsole() {
                Console.getInstance().registerOutputListener(this);
                Console.getInstance().registerErrorListener(this);
                Console.getInstance().registerTraceListener(this);
                Console.getInstance().registerExceptionListener(this);
        }

        /**
         * <p>
         * Prints messages to {@code stdout}.
         * </p>
         * 
         * @see ConsoleObserver#outputMsg(java.lang.String)
         */
        public void outputMsg(String newMessage) {
                System.out.print(newMessage);
        }

        /**
         * <p>
         * Prints messages to {@code stderr}.
         * </p>
         * 
         * @see ConsoleObserver#errorMsg(String)
         */
        @Override
        public void errorMsg(String errMessage) {
                System.err.print(errMessage);
        }

        /**
         * <p>
         * Prints the stacktrace of an exception to {@code stderr}.
         * </p>
         * 
         * @see ConsoleObserver#logException(Exception)
         */
        @Override
        public void logException(Exception e) {
                System.err.println(e.getMessage());
        }

        /**
         * <p>
         * Prints messages to {@code stdout}. These messages are only printed, if
         * the console is run in debug mode.
         * </p>
         */
        @Override
        public void traceMsg(String traceMessage) {
                if (debugMode) {
                        System.out.print(traceMessage);
                }
        }

        /**
         * <p>
         * Starts a new TextConsole. If the text console is started, it can be used
         * not only to print message, but also to execute commands by reading
         * {@code stdin}.
         * </p>
         * 
         * @param debugMode
         *            true, if the application is to run in debug mode, i.e. trace
         *            messages will be printed
         */
        public void run(boolean debugMode) {
                this.debugMode = debugMode;
                CommandExecuter exec = CommandExecuter.getInstance();
                while (true) {
                        System.out.print("> ");
                        String command = getCommand().trim();
                        if (!command.equals("")) {
                                exec.exec(command);
                        }
                }
        }

        /**
         * <p>
         * Reads a new command from {@code stdin}.
         * </p>
         * 
         * @return a string with a command
         */
        protected String getCommand() {
                byte[] buffer = new byte[1024];
                int bytesRead = 0;
                String command;
                try {
                        bytesRead = System.in.read(buffer);
                } catch (IOException e) {

                }
                if (bytesRead == 0) {
                        command = "";
                } else {
                        command = new String(buffer, Charset.defaultCharset());
                }
                return command;
        }

        /**
         * <p>
         * Configures if the debug mode of the text console is enabled.
         * </p>
         * 
         * @param debug
         *            if true, debug mode is enabled.
         */
        public void setDebug(boolean debug) {
                debugMode = debug;
        }

}