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    
020    package org.crsh.shell.impl.command;
021    
022    import org.crsh.command.CommandContext;
023    import org.crsh.command.CommandInvoker;
024    import org.crsh.text.Chunk;
025    
026    import java.io.IOException;
027    
028    class PipeLine implements CommandInvoker<Void, Chunk> {
029    
030      /** . */
031      private final CommandInvoker[] invokers;
032    
033      /** . */
034      private Pipe.Invoker current;
035    
036      PipeLine(CommandInvoker[] invokers) {
037        this.invokers = invokers;
038        this.current = null;
039      }
040    
041      public Class<Void> getConsumedType() {
042        throw new UnsupportedOperationException();
043      }
044    
045      public Class<Chunk> getProducedType() {
046        throw new UnsupportedOperationException();
047      }
048    
049      public void setPiped(boolean piped) {
050        throw new UnsupportedOperationException("This should not be called");
051      }
052    
053      public void open(CommandContext<Chunk> consumer) {
054        open(0, consumer);
055      }
056    
057      private CommandContext open(final int index, final CommandContext last) {
058        if (index < invokers.length) {
059    
060          //
061          final CommandInvoker invoker = invokers[index];
062          CommandContext next = open(index + 1, last);
063    
064          //
065          final Class produced = invoker.getProducedType();
066          final Class<?> consumed = next.getConsumedType();
067    
068          if (!consumed.isAssignableFrom(produced)) {
069            if (produced.equals(Void.class) || consumed.equals(Void.class)) {
070              // We need to check (i.e test) what happens for chunk (i.e the writer)
071              Pipe.Sink filter = new Pipe.Sink(consumed);
072              filter.open(next);
073              next = filter;
074            } else if (consumed.equals(Chunk.class)) {
075              Pipe.Chunkizer filter = new Pipe.Chunkizer();
076              filter.open((CommandContext<Chunk>)next);
077              next = filter;
078            } else {
079              Pipe.Sink filter = new Pipe.Sink(consumed);
080              filter.open(next);
081              next = filter;
082            }
083          }
084    
085          //
086          Pipe.Invoker filterContext = new Pipe.Invoker(invoker);
087          filterContext.setPiped(index > 0);
088          filterContext.open(next);
089    
090          // Save current filter in field
091          // so if anything wrong happens it will be closed
092          current = filterContext;
093    
094          //
095          return filterContext;
096        } else {
097          return last;
098        }
099      }
100    
101      public void provide(Void element) throws IOException {
102        throw new UnsupportedOperationException("This is not yet implemented");
103      }
104    
105      public void flush() throws IOException {
106        current.flush();
107      }
108    
109      public void close() {
110        current.close();
111      }
112    }