src/org/sonews/daemon/CommandSelector.java
author cli
Sun Aug 29 18:17:37 2010 +0200 (2010-08-29)
changeset 37 74139325d305
parent 35 ed84c8bdd87b
permissions -rw-r--r--
Switch intent style to Original K&R / Linux / Kernel.
chris@3
     1
/*
chris@3
     2
 *   SONEWS News Server
chris@3
     3
 *   see AUTHORS for the list of contributors
chris@3
     4
 *
chris@3
     5
 *   This program is free software: you can redistribute it and/or modify
chris@3
     6
 *   it under the terms of the GNU General Public License as published by
chris@3
     7
 *   the Free Software Foundation, either version 3 of the License, or
chris@3
     8
 *   (at your option) any later version.
chris@3
     9
 *
chris@3
    10
 *   This program is distributed in the hope that it will be useful,
chris@3
    11
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
chris@3
    12
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
chris@3
    13
 *   GNU General Public License for more details.
chris@3
    14
 *
chris@3
    15
 *   You should have received a copy of the GNU General Public License
chris@3
    16
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
chris@3
    17
 */
chris@3
    18
chris@3
    19
package org.sonews.daemon;
chris@3
    20
chris@3
    21
import java.util.HashMap;
chris@3
    22
import java.util.Map;
cli@26
    23
import java.util.Set;
chris@3
    24
import java.util.concurrent.ConcurrentHashMap;
chris@3
    25
import org.sonews.daemon.command.Command;
chris@3
    26
import org.sonews.daemon.command.UnsupportedCommand;
chris@3
    27
import org.sonews.util.Log;
chris@3
    28
import org.sonews.util.io.Resource;
chris@3
    29
chris@3
    30
/**
chris@3
    31
 * Selects the correct command processing class.
chris@3
    32
 * @author Christian Lins
cli@21
    33
 * @since sonews/1.0
chris@3
    34
 */
cli@21
    35
public class CommandSelector
chris@3
    36
{
chris@3
    37
cli@37
    38
	private static Map<Thread, CommandSelector> instances = new ConcurrentHashMap<Thread, CommandSelector>();
cli@37
    39
	private static Map<String, Class<?>> commandClassesMapping = new ConcurrentHashMap<String, Class<?>>();
chris@3
    40
cli@37
    41
	static {
cli@37
    42
		String[] classes = Resource.getAsString("helpers/commands.list", true).split("\n");
cli@37
    43
		for (String className : classes) {
cli@37
    44
			if (className.charAt(0) == '#') {
cli@37
    45
				// Skip comments
cli@37
    46
				continue;
cli@37
    47
			}
cli@10
    48
cli@37
    49
			try {
cli@37
    50
				addCommandHandler(className);
cli@37
    51
			} catch (ClassNotFoundException ex) {
cli@37
    52
				Log.get().warning("Could not load command class: " + ex);
cli@37
    53
			} catch (InstantiationException ex) {
cli@37
    54
				Log.get().severe("Could not instantiate command class: " + ex);
cli@37
    55
			} catch (IllegalAccessException ex) {
cli@37
    56
				Log.get().severe("Could not access command class: " + ex);
cli@37
    57
			}
cli@37
    58
		}
cli@37
    59
	}
chris@3
    60
cli@37
    61
	public static void addCommandHandler(String className)
cli@37
    62
		throws ClassNotFoundException, InstantiationException,
cli@37
    63
		IllegalAccessException
cli@37
    64
	{
cli@37
    65
		Class<?> clazz = Class.forName(className);
cli@37
    66
		Command cmd = (Command) clazz.newInstance();
cli@37
    67
		String[] cmdStrs = cmd.getSupportedCommandStrings();
cli@37
    68
		for (String cmdStr : cmdStrs) {
cli@37
    69
			commandClassesMapping.put(cmdStr, clazz);
cli@37
    70
		}
cli@37
    71
	}
cli@21
    72
cli@37
    73
	public static Set<String> getCommandNames()
cli@37
    74
	{
cli@37
    75
		return commandClassesMapping.keySet();
cli@37
    76
	}
cli@26
    77
cli@37
    78
	public static CommandSelector getInstance()
cli@37
    79
	{
cli@37
    80
		CommandSelector csel = instances.get(Thread.currentThread());
cli@37
    81
		if (csel == null) {
cli@37
    82
			csel = new CommandSelector();
cli@37
    83
			instances.put(Thread.currentThread(), csel);
cli@37
    84
		}
cli@37
    85
		return csel;
cli@37
    86
	}
cli@37
    87
	private Map<String, Command> commandMapping = new HashMap<String, Command>();
cli@37
    88
	private Command unsupportedCmd = new UnsupportedCommand();
cli@21
    89
cli@37
    90
	private CommandSelector()
cli@37
    91
	{
cli@37
    92
	}
cli@21
    93
cli@37
    94
	public Command get(String commandName)
cli@37
    95
	{
cli@37
    96
		try {
cli@37
    97
			commandName = commandName.toUpperCase();
cli@37
    98
			Command cmd = this.commandMapping.get(commandName);
cli@21
    99
cli@37
   100
			if (cmd == null) {
cli@37
   101
				Class<?> clazz = commandClassesMapping.get(commandName);
cli@37
   102
				if (clazz == null) {
cli@37
   103
					cmd = this.unsupportedCmd;
cli@37
   104
				} else {
cli@37
   105
					cmd = (Command) clazz.newInstance();
cli@37
   106
					this.commandMapping.put(commandName, cmd);
cli@37
   107
				}
cli@37
   108
			} else if (cmd.isStateful()) {
cli@37
   109
				cmd = cmd.getClass().newInstance();
cli@37
   110
			}
chris@3
   111
cli@37
   112
			return cmd;
cli@37
   113
		} catch (Exception ex) {
cli@37
   114
			ex.printStackTrace();
cli@37
   115
			return this.unsupportedCmd;
cli@37
   116
		}
cli@37
   117
	}
chris@3
   118
}