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