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 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 open(CommandContext<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 if (!consumed.isAssignableFrom(produced)) {
065 if (produced.equals(Void.class) || consumed.equals(Void.class)) {
066 // We need to check (i.e test) what happens for chunk (i.e the writer)
067 PipeFilter.Sink filter = new PipeFilter.Sink(consumed, piped);
068 filter.open(next);
069 next = filter;
070 } else if (consumed.equals(Chunk.class)) {
071 PipeFilter.Chunkizer filter = new PipeFilter.Chunkizer(piped);
072 filter.open((CommandContext<Chunk>)next);
073 next = filter;
074 } else {
075 PipeFilter.Sink filter = new PipeFilter.Sink(consumed, piped);
076 filter.open(next);
077 next = filter;
078 }
079 } else {
080 PipeFilter.Noop filter = new PipeFilter.Noop(piped);
081 filter.open(next);
082 next = filter;
083 }
084
085 //
086 Pipe filterContext = new Pipe(invoker);
087 filterContext.open(next);
088
089 // Save current filter in field
090 // so if anything wrong happens it will be closed
091 current = filterContext;
092
093 //
094 return filterContext;
095 } else {
096 return last;
097 }
098 }
099
100 public void provide(Void element) throws IOException {
101 throw new UnsupportedOperationException("This is not yet implemented");
102 }
103
104 public void flush() throws IOException {
105 current.flush();
106 }
107
108 public void close() throws IOException {
109 current.close();
110 }
111 }