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