src/main/java/net/pterodactylus/sonitus/data/source/MultiSource.java

   1 /*
   2  * Sonitus - MultiSource.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sonitus.data.source;
  19
  20 import static com.google.common.base.Preconditions.checkNotNull;
  21
  22 import java.io.EOFException;
  23 import java.io.IOException;
  24 import java.util.Collections;
  25 import java.util.List;
  26 import java.util.concurrent.atomic.AtomicReference;
  27 import java.util.logging.Logger;
  28
  29 import net.pterodactylus.sonitus.data.Controller;
  30 import net.pterodactylus.sonitus.data.Metadata;
  31 import net.pterodactylus.sonitus.data.Source;
  32 import net.pterodactylus.sonitus.data.event.SourceFinishedEvent;
  33
  34 import com.google.common.eventbus.EventBus;
  35 import com.google.inject.Inject;
  36
  37 /**
  38  * {@link Source} implementation that simply forwards another source and
  39  * supports changing the source without letting the {@link
  40  * net.pterodactylus.sonitus.data.Sink} know.
  41  *
  42  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  43  */
  44 public class MultiSource implements Source {
  45
  46         /** The logger. */
  47         private static final Logger logger = Logger.getLogger(MultiSource.class.getName());
  48
  49         /** The event bus. */
  50         private final EventBus eventBus;
  51
  52         /** The current source. */
  53         private final AtomicReference<Source> source = new AtomicReference<Source>();
  54
  55         /** Whether the source was changed. */
  56         private boolean sourceChanged;
  57
  58         @Inject
  59         public MultiSource(EventBus eventBus) {
  60                 this.eventBus = eventBus;
  61         }
  62
  63         //
  64         // ACTIONS
  65         //
  66
  67         /**
  68          * Sets the new source to use.
  69          *
  70          * @param source
  71          *              The new source to use
  72          */
  73         public void setSource(Source source) {
  74                 checkNotNull(source, "source must not be null");
  75
  76                 Source oldSource = this.source.getAndSet(source);
  77                 if (oldSource != null) {
  78                         synchronized (this.source) {
  79                                 sourceChanged = true;
  80                                 this.source.notifyAll();
  81                         }
  82                         logger.info(String.format("Next Source set: %s", source));
  83                 }
  84         }
  85
  86         //
  87         // CONTROLLED METHODS
  88         //
  89
  90         @Override
  91         public String name() {
  92                 return "Multisource";
  93         }
  94
  95         @Override
  96         public List<Controller<?>> controllers() {
  97                 return Collections.emptyList();
  98         }
  99
 100         //
 101         // SOURCE METHODS
 102         //
 103
 104         @Override
 105         public Metadata metadata() {
 106                 return source.get().metadata();
 107         }
 108
 109         @Override
 110         public byte[] get(int bufferSize) throws EOFException, IOException {
 111                 while (true) {
 112                         try {
 113                                 return source.get().get(bufferSize);
 114                         } catch (EOFException eofe1) {
 115                                 eventBus.post(new SourceFinishedEvent(source.get()));
 116                                 synchronized (source) {
 117                                         while (!sourceChanged) {
 118                                                 try {
 119                                                         logger.info("Waiting for next Source...");
 120                                                         source.wait();
 121                                                         logger.info("Was notified.");
 122                                                 } catch (InterruptedException ioe1) {
 123                                                         /* ignore: we’ll end up here again if we were interrupted. */
 124                                                 }
 125                                         }
 126                                 }
 127                         } finally {
 128                                 synchronized (source) {
 129                                         sourceChanged = false;
 130                                 }
 131                         }
 132                 }
 133         }
 134
 135 }