001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    package org.crsh.shell.impl.command.system;
020    
021    import org.crsh.cli.descriptor.Format;
022    import org.crsh.cli.impl.descriptor.IntrospectionException;
023    import org.crsh.command.BaseCommand;
024    import org.crsh.shell.ErrorKind;
025    import org.crsh.shell.impl.command.spi.CommandException;
026    import org.crsh.lang.impl.java.ClassShellCommand;
027    import org.crsh.shell.impl.command.spi.CommandResolver;
028    import org.crsh.lang.spi.CommandResolution;
029    import org.crsh.shell.impl.command.spi.Command;
030    
031    import java.util.HashMap;
032    import java.util.Map;
033    
034    /**
035     * @author Julien Viet
036     */
037    public class SystemResolver implements CommandResolver {
038    
039      /** . */
040      public static final SystemResolver INSTANCE = new SystemResolver();
041    
042      /** . */
043      private static final HashMap<String, Class<? extends BaseCommand>> commands = new HashMap<String, Class<? extends BaseCommand>>();
044    
045      /** . */
046      private static final HashMap<String, String> descriptions = new HashMap<String, String>();
047    
048      static {
049        commands.put("help", help.class);
050        commands.put("repl", repl.class);
051        descriptions.put("help", "provides basic help");
052        descriptions.put("repl", "list the repl or change the current repl");
053      }
054    
055      private SystemResolver() {
056      }
057    
058      @Override
059      public Iterable<Map.Entry<String, String>> getDescriptions() {
060        return descriptions.entrySet();
061      }
062    
063      @Override
064      public Command<?> resolveCommand(String name) throws CommandException, NullPointerException {
065        final Class<? extends BaseCommand> systemCommand = commands.get(name);
066        if (systemCommand != null) {
067          return createCommand(systemCommand).getCommand();
068        }
069        return null;
070      }
071    
072      private <C extends BaseCommand> CommandResolution createCommand(final Class<C> commandClass) throws CommandException {
073        final ClassShellCommand<C> shellCommand;
074        final String description;
075        try {
076          shellCommand = new ClassShellCommand<C>(commandClass);
077          description = shellCommand.describe(commandClass.getSimpleName(), Format.DESCRIBE);
078        }
079        catch (IntrospectionException e) {
080          throw new CommandException(ErrorKind.SYNTAX, "Invalid cli annotation in command " + commandClass.getSimpleName(), e);
081        }
082        return new CommandResolution() {
083          @Override
084          public String getDescription() {
085            return description;
086          }
087          @Override
088          public Command<?> getCommand() throws CommandException {
089            return shellCommand;
090          }
091        };
092      }
093    }