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.AbstractControlledComponent;
  30 import net.pterodactylus.sonitus.data.Controller;
  31 import net.pterodactylus.sonitus.data.Metadata;
  32 import net.pterodactylus.sonitus.data.Source;
  33 import net.pterodactylus.sonitus.data.event.MetadataUpdated;
  34 import net.pterodactylus.sonitus.data.event.SourceFinishedEvent;
  35
  36 import com.google.common.eventbus.EventBus;
  37 import com.google.inject.Inject;
  38
  39 /**
  40  * {@link Source} implementation that simply forwards another source and
  41  * supports changing the source without letting the {@link
  42  * net.pterodactylus.sonitus.data.Sink} know.
  43  *
  44  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  45  */
  46 public class MultiSource extends AbstractControlledComponent implements Source {
  47
  48         /** The logger. */
  49         private static final Logger logger = Logger.getLogger(MultiSource.class.getName());
  50
  51         /** The event bus. */
  52         private final EventBus eventBus;
  53
  54         /** The current source. */
  55         private final AtomicReference<Source> source = new AtomicReference<Source>();
  56
  57         /** Whether the source was changed. */
  58         private boolean sourceChanged;
  59
  60         /**
  61          * Creates a new multi source.
  62          *
  63          * @param eventBus
  64          *              The event bus
  65          */
  66         @Inject
  67         public MultiSource(EventBus eventBus) {
  68                 this.eventBus = eventBus;
  69         }
  70
  71         //
  72         // ACTIONS
  73         //
  74
  75         /**
  76          * Sets the new source to use.
  77          *
  78          * @param source
  79          *              The new source to use
  80          */
  81         public void setSource(Source source) {
  82                 checkNotNull(source, "source must not be null");
  83
  84                 Source oldSource = this.source.getAndSet(source);
  85                 if (oldSource != null) {
  86                         synchronized (this.source) {
  87                                 sourceChanged = true;
  88                                 this.source.notifyAll();
  89                         }
  90                         fireMetadataUpdated(source.metadata());
  91                         eventBus.post(new MetadataUpdated(this, source.metadata()));
  92                         logger.info(String.format("Next Source set: %s", source));
  93                 }
  94         }
  95
  96         //
  97         // CONTROLLED METHODS
  98         //
  99
 100         @Override
 101         public String name() {
 102                 return "Multisource";
 103         }
 104
 105         @Override
 106         public List<Controller<?>> controllers() {
 107                 return Collections.emptyList();
 108         }
 109
 110         //
 111         // SOURCE METHODS
 112         //
 113
 114         @Override
 115         public Metadata metadata() {
 116                 return source.get().metadata();
 117         }
 118
 119         @Override
 120         public byte[] get(int bufferSize) throws EOFException, IOException {
 121                 while (true) {
 122                         try {
 123                                 return source.get().get(bufferSize);
 124                         } catch (EOFException eofe1) {
 125                                 eventBus.post(new SourceFinishedEvent(source.get()));
 126                                 synchronized (source) {
 127                                         while (!sourceChanged) {
 128                                                 try {
 129                                                         logger.info("Waiting for next Source...");
 130                                                         source.wait();
 131                                                         logger.info("Was notified.");
 132                                                 } catch (InterruptedException ioe1) {
 133                                                         /* ignore: we’ll end up here again if we were interrupted. */
 134                                                 }
 135                                         }
 136                                 }
 137                         } finally {
 138                                 synchronized (source) {
 139                                         sourceChanged = false;
 140                                 }
 141                         }
 142                 }
 143         }
 144
 145 }