gogo/src/main/java/aQute/shell/console/Console.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package aQute.shell.console;

import java.io.*;
import java.lang.reflect.*;
import java.util.*;

import org.osgi.service.command.*;

public class Console implements Runnable {
	StringBuilder		sb;
	CommandSession		session;
	List<CharSequence>	history	= new ArrayList<CharSequence>();
	int					current	= 0;
	boolean				quit;

	public void setSession(CommandSession session) {
	    this.session= session;
	}
	
	public void run() {
		try {
			while (!quit) {
				try {
					CharSequence line = getLine(session.getKeyboard());
					if (line != null) {
						history.add(line);
						if (history.size() > 40)
							history.remove(0);
						Object result = session.execute(line);
						if (result != null)
							session.getConsole().println(
									session.format(result, Converter.INSPECT));
					} else
						quit = true;

				} catch (InvocationTargetException ite) {
					session.getConsole().println(
							"E: " + ite.getTargetException());
					session.put("exception", ite.getTargetException());
				} catch (Throwable e) {
					if (!quit) {
						session.getConsole().println("E: " + e.getMessage());
						session.put("exception", e);
					}
				}
			}
		} catch (Exception e) {
			if (!quit)
				e.printStackTrace();
		}
	}

	CharSequence getLine(InputStream in) throws IOException {
		sb = new StringBuilder();
		session.getConsole().print("$ ");
		int outer = 0;
		while (!quit) {
			session.getConsole().flush();
			int c = in.read();
			if (c < 0)
				quit = true;
			else {
				switch (c) {
				case '\r':
				    break;
				case '\n':
					if (outer == 0 && sb.length() > 0) {
						return sb;
					} else {
					        session.getConsole().print("$ ");
					}
					break;

				case '\u001b':
					c = in.read();
					if (c == '[') {
						c = in.read();
						session.getConsole().print("\b\b\b");
						switch (c) {
						case 'A':
							history(current - 1);
							break;
						case 'B':
							history(current + 1);
							break;
						case 'C': // right(); break;
						case 'D': // left(); break;
						}
					}
					break;

				case '\b':
					if (sb.length() > 0) {
						session.getConsole().print("\b \b");
						sb.deleteCharAt(sb.length() - 1);
					}
					break;

				default:
					sb.append((char) c);
					break;
				}
			}
		}
		return null;
	}

	void history(int n) {
		if (n < 0 || n > history.size())
			return;
		current = n;
		for (int i = 0; i < sb.length(); i++)
			session.getConsole().print("\b \b");

		sb = new StringBuilder(history.get(current));
		session.getConsole().print(sb);
	}

    public void close() {
        quit = true;
    }
    
    public void open() {}
}