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
020package org.crsh.shell.impl.command.pipeline;
021
022import org.crsh.command.CommandContext;
023import org.crsh.shell.impl.command.spi.CommandInvoker;
024import org.crsh.console.KeyHandler;
025import org.crsh.text.Chunk;
026
027import java.io.IOException;
028
029public class PipeLine extends CommandInvoker<Void, Chunk> {
030
031  /** . */
032  private final CommandInvoker[] invokers;
033
034  /** . */
035  private CommandContext<?> current;
036
037  public PipeLine(CommandInvoker[] invokers) {
038    this.invokers = invokers;
039    this.current = null;
040  }
041
042  public Class<Void> getConsumedType() {
043    return Void.class;
044  }
045
046  public Class<Chunk> getProducedType() {
047    return Chunk.class;
048  }
049
050  public void open(CommandContext<? super Chunk> consumer) {
051    open(0, consumer);
052  }
053
054  private CommandContext open(final int index, final CommandContext last) {
055    if (index < invokers.length) {
056
057      //
058      final CommandInvoker invoker = invokers[index];
059      CommandContext next = open(index + 1, last);
060
061      //
062      final Class produced = invoker.getProducedType();
063      final Class<?> consumed = next.getConsumedType();
064      boolean piped = index > 0;
065
066      AbstractPipe filter;
067      if (consumed.equals(Chunk.class)) {
068        filter = new ToChunkPipe(produced, piped);
069      } else {
070        filter = new ConvertingPipe(produced, consumed, piped);
071      }
072      filter.open(next);
073      next = filter;
074
075      //
076      PipeLineElement filterContext = new PipeLineElement(invoker);
077      filterContext.open(next);
078
079      // Save current filter in field
080      // so if anything wrong happens it will be closed
081      current = filterContext;
082
083      //
084      return filterContext;
085    } else {
086      current = last;
087      return last;
088    }
089  }
090
091  @Override
092  public KeyHandler getKeyHandler() {
093    for (CommandInvoker<?, ?> invoker : invokers) {
094      KeyHandler handler = invoker.getKeyHandler();
095      if (handler != null) {
096        return handler;
097      }
098    }
099    return null;
100  }
101
102  public void provide(Void element) throws IOException {
103    // Ignore
104  }
105
106  public void flush() throws IOException {
107    current.flush();
108  }
109
110  public void close() throws IOException {
111    current.close();
112  }
113}