Command Parser.

src/main/java/com/loomcom/j6502/CommandParser.java

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+package com.loomcom.j6502;
+
+import java.io.*;
+
+public class CommandParser {
+    
+    private BufferedReader m_in;
+    private BufferedWriter m_out;
+    
+    public CommandParser(InputStream in, OutputStream out) {
+	m_in  = new BufferedReader(new InputStreamReader(in));
+	m_out = new BufferedWriter(new OutputStreamWriter(out));
+    }
+
+    public void run() {
+	try {
+	    String command = null;
+	    greeting();
+	    prompt();
+	    while (!shouldQuit(command = readLine())) {
+		dispatch(command);
+		prompt();
+	    }
+	    writeLine("Goodbye!");
+	} catch (IOException ex) {
+	    System.err.println("Error: " + ex.toString());
+	    System.exit(1);
+	}
+    }
+    
+    /**
+     * Dispatch the command.
+     */
+    public void dispatch(String command) throws IOException {
+	writeLine("You entered: " + command);
+    }
+
+    /*******************************************************************
+     * Private
+     *******************************************************************/
+
+    private void greeting() throws IOException {
+	writeLine("Welcome to the j6502 Simulator!");
+    }
+
+    private void prompt() throws IOException {
+	m_out.write("> ");
+	m_out.flush();
+    }
+
+    private String readLine() throws IOException {
+	String line = m_in.readLine();
+	if (line == null) { return null; }
+	return line.trim();
+    }
+
+    private void writeLine(String line) throws IOException {
+	m_out.write(line);
+	m_out.newLine();
+	m_out.flush();
+    }
+    
+    /**
+     * Returns true if the line is a quit.
+     */
+    private boolean shouldQuit(String line) {
+	return (line == null || "q".equals(line.toLowerCase()));
+    }
+    
+}