org.crsh.command.pipeline.PipeLine Maven / Gradle / Ivy

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/*
 * Copyright (C) 2012 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.crsh.command.pipeline;

import org.crsh.command.CommandContext;
import org.crsh.command.CommandInvoker;
import org.crsh.text.Chunk;

import java.io.IOException;

public class PipeLine extends CommandInvoker {

  /** . */
  private final CommandInvoker[] invokers;

  /** . */
  private CommandContext current;

  public PipeLine(CommandInvoker[] invokers) {
    this.invokers = invokers;
    this.current = null;
  }

  public Class getConsumedType() {
    return Void.class;
  }

  public Class getProducedType() {
    return Chunk.class;
  }

  public void open(CommandContext consumer) {
    open(0, consumer);
  }

  private CommandContext open(final int index, final CommandContext last) {
    if (index < invokers.length) {

      //
      final CommandInvoker invoker = invokers[index];
      CommandContext next = open(index + 1, last);

      //
      final Class produced = invoker.getProducedType();
      final Class consumed = next.getConsumedType();
      boolean piped = index > 0;

      AbstractPipe filter;
      if (consumed.equals(Chunk.class)) {
        filter = new ToChunkPipe(produced, piped);
      } else {
        filter = new ConvertingPipe(produced, consumed, piped);
      }
      filter.open(next);
      next = filter;

      //
      PipeLineElement filterContext = new PipeLineElement(invoker);
      filterContext.open(next);

      // Save current filter in field
      // so if anything wrong happens it will be closed
      current = filterContext;

      //
      return filterContext;
    } else {
      current = last;
      return last;
    }
  }

  public void provide(Void element) throws IOException {
    // Ignore
  }

  public void flush() throws IOException {
    current.flush();
  }

  public void close() throws IOException {
    current.close();
  }
}