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 */
019package org.crsh.lang.impl.java;
020
021import org.crsh.cli.descriptor.CommandDescriptor;
022import org.crsh.cli.impl.descriptor.HelpDescriptor;
023import org.crsh.cli.impl.descriptor.IntrospectionException;
024import org.crsh.cli.impl.invocation.InvocationMatch;
025import org.crsh.cli.impl.lang.CommandFactory;
026import org.crsh.cli.impl.lang.Instance;
027import org.crsh.cli.impl.lang.ObjectCommandInvoker;
028import org.crsh.cli.spi.Completer;
029import org.crsh.command.BaseCommand;
030import org.crsh.shell.ErrorKind;
031import org.crsh.shell.impl.command.spi.Command;
032import org.crsh.shell.impl.command.spi.CommandException;
033import org.crsh.shell.impl.command.spi.CommandMatch;
034import org.crsh.command.InvocationContext;
035import org.crsh.command.Pipe;
036import org.crsh.command.RuntimeContext;
037import org.crsh.util.Utils;
038
039import java.lang.reflect.InvocationTargetException;
040import java.lang.reflect.Type;
041
042/** @author Julien Viet */
043public class ClassShellCommand<T extends BaseCommand> extends Command<Instance<T>> {
044
045  /** . */
046  private final Class<T> clazz;
047
048  /** . */
049  private final CommandDescriptor<Instance<T>> descriptor;
050
051  public ClassShellCommand(Class<T> clazz) throws IntrospectionException {
052    CommandFactory factory = new CommandFactory(getClass().getClassLoader());
053    this.clazz = clazz;
054    this.descriptor = HelpDescriptor.create(factory.create(clazz));
055  }
056
057  public CommandDescriptor<Instance<T>> getDescriptor() {
058    return descriptor;
059  }
060
061  protected Completer getCompleter(final RuntimeContext context) throws CommandException {
062    final T command = createCommand();
063    if (command instanceof Completer) {
064      command.context = context;
065      return (Completer)command;
066    } else {
067      return null;
068    }
069  }
070
071  @Override
072  protected CommandMatch<?, ?> resolve(InvocationMatch<Instance<T>> match) {
073
074    // Cast to the object invoker
075    org.crsh.cli.impl.invocation.CommandInvoker<Instance<T>,?> invoker = match.getInvoker();
076
077    // Do we have a pipe command or not ?
078    if (Pipe.class.isAssignableFrom(invoker.getReturnType())) {
079      org.crsh.cli.impl.invocation.CommandInvoker tmp = invoker;
080      return getPipeInvoker(tmp);
081    } else {
082
083      // Determine the produced type
084      Class<?> producedType;
085      if (void.class.equals(invoker.getReturnType())) {
086        producedType = Object.class;
087      } else {
088        producedType = invoker.getReturnType();
089      }
090
091      // Override produced type from InvocationContext<P> if any
092      if (invoker instanceof ObjectCommandInvoker) {
093        ObjectCommandInvoker<T, ?> objectInvoker = (ObjectCommandInvoker<T, ?>)invoker;
094        Class<?>[] parameterTypes = objectInvoker.getParameterTypes();
095        for (int i = 0;i < parameterTypes.length;i++) {
096          Class<?> parameterType = parameterTypes[i];
097          if (InvocationContext.class.isAssignableFrom(parameterType)) {
098            Type contextGenericParameterType = objectInvoker.getGenericParameterTypes()[i];
099            producedType = Utils.resolveToClass(contextGenericParameterType, InvocationContext.class, 0);
100            break;
101          }
102        }
103      }
104
105      //
106      return getProducerInvoker(invoker, producedType);
107    }
108  }
109
110  T createCommand() throws CommandException {
111    T command;
112    try {
113      command = clazz.getConstructor().newInstance();
114    }
115    catch (InvocationTargetException e) {
116      String name = clazz.getSimpleName();
117      throw new CommandException(ErrorKind.EVALUATION, "Could not create command " + name + " instance", e.getCause());
118    }
119    catch (Exception e) {
120      String name = clazz.getSimpleName();
121      throw new CommandException(ErrorKind.INTERNAL, "Could not create command " + name + " instance", e);
122    }
123    return command;
124  }
125
126  private <C, P, PC extends Pipe<C, P>> CommandMatch<C, P> getPipeInvoker(final org.crsh.cli.impl.invocation.CommandInvoker<Instance<T>, PC> invoker) {
127    return new PipeCommandMatch<T, C, P, PC>(this, invoker);
128  }
129
130  private <P> CommandMatch<Void, P> getProducerInvoker(final org.crsh.cli.impl.invocation.CommandInvoker<Instance<T>, ?> invoker, final Class<P> producedType) {
131    return new ProducerCommandMatch<T, P>(this, invoker, producedType);
132  }
133
134}