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.shell.InteractionContext;
025    import org.crsh.text.Chunk;
026    
027    import java.io.IOException;
028    
029    class PipeLine implements CommandInvoker<Void, Chunk> {
030    
031      /** . */
032      private final CommandInvoker[] invokers;
033    
034      /** . */
035      private Pipe.Invoker current;
036    
037      PipeLine(CommandInvoker[] invokers) {
038        this.invokers = invokers;
039        this.current = null;
040      }
041    
042      public void setSession(CommandContext session) {
043        // Should we use it ?
044      }
045    
046      public Class<Void> getConsumedType() {
047        throw new UnsupportedOperationException();
048      }
049    
050      public Class<Chunk> getProducedType() {
051        throw new UnsupportedOperationException();
052      }
053    
054      public void setPiped(boolean piped) {
055        throw new UnsupportedOperationException("This should not be called");
056      }
057    
058      public void open(InteractionContext<Chunk> consumer) {
059        open(0, consumer);
060      }
061    
062      private InteractionContext open(final int index, final InteractionContext last) {
063        if (index < invokers.length) {
064    
065          //
066          final CommandInvoker invoker = invokers[index];
067          InteractionContext next = open(index + 1, last);
068    
069          //
070          final Class produced = invoker.getProducedType();
071          final Class<?> consumed = next.getConsumedType();
072    
073          if (!consumed.isAssignableFrom(produced)) {
074            if (produced.equals(Void.class) || consumed.equals(Void.class)) {
075              // We need to check (i.e test) what happens for chunk (i.e the writer)
076              Pipe.Sink filter = new Pipe.Sink(consumed);
077              filter.open(next);
078              next = filter;
079            } else if (consumed.equals(Chunk.class)) {
080              Pipe.Chunkizer filter = new Pipe.Chunkizer();
081              filter.open((InteractionContext<Chunk>)next);
082              next = filter;
083            } else {
084              Pipe.Sink filter = new Pipe.Sink(consumed);
085              filter.open(next);
086              next = filter;
087            }
088          }
089    
090          //
091          Pipe.Invoker filterContext = new Pipe.Invoker(invoker);
092          filterContext.setPiped(index > 0);
093          filterContext.open(next);
094    
095          // Save current filter in field
096          // so if anything wrong happens it will be closed
097          current = filterContext;
098    
099          //
100          return filterContext;
101        } else {
102          return last;
103        }
104      }
105    
106      public void provide(Void element) throws IOException {
107        throw new UnsupportedOperationException("This is not yet implemented");
108      }
109    
110      public void flush() throws IOException {
111        current.flush();
112      }
113    
114      public void close() {
115        current.close();
116      }
117    }