src/main/java/net/pterodactylus/sonitus/data/filter/PipelineFilter.java

   1 /*
   2  * Sonitus - PipelineFilter.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.filter;
  19
  20 import java.io.IOException;
  21 import java.util.Arrays;
  22 import java.util.Collection;
  23 import java.util.List;
  24 import java.util.Map;
  25 import java.util.logging.Logger;
  26
  27 import net.pterodactylus.sonitus.data.AbstractFilter;
  28 import net.pterodactylus.sonitus.data.DataPacket;
  29 import net.pterodactylus.sonitus.data.Filter;
  30 import net.pterodactylus.sonitus.data.Metadata;
  31 import net.pterodactylus.sonitus.data.Pipeline.Connection;
  32
  33 import com.google.common.collect.Lists;
  34 import com.google.common.collect.Maps;
  35
  36 /**
  37  * {@link Filter} that combines several filters into one.
  38  *
  39  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  40  */
  41 public class PipelineFilter extends AbstractFilter implements Filter {
  42
  43         /** The logger. */
  44         private static final Logger logger = Logger.getLogger(PipelineFilter.class.getName());
  45
  46         /** The first filter. */
  47         private final Filter source;
  48
  49         /** All following filters. */
  50         private final List<Filter> filters = Lists.newArrayList();
  51
  52         /** The last filter (for convenience). */
  53         private final Filter lastFilter;
  54
  55         /** The connections for each filter. */
  56         private final Map<Filter, Connection> filterConnections = Maps.newHashMap();
  57
  58         /**
  59          * Creates a new pipeline filter.
  60          *
  61          * @param name
  62          *              The name of the filter
  63          * @param source
  64          *              The first source of the filter
  65          * @param filters
  66          *              All other filters in correct order
  67          */
  68         private PipelineFilter(String name, Filter source, Collection<Filter> filters) {
  69                 super(name);
  70                 this.source = source;
  71                 this.filters.addAll(filters);
  72                 this.lastFilter = this.filters.get(filters.size() - 1);
  73         }
  74
  75         //
  76         // FILTER METHODS
  77         //
  78
  79         @Override
  80         public Metadata metadata() {
  81                 return lastFilter.metadata();
  82         }
  83
  84         @Override
  85         public void open(Metadata metadata) throws IOException {
  86                 /* open the source and all filters in the correct order. */
  87                 source.open(metadata);
  88                 Metadata currentMetadata = source.metadata();
  89                 Filter currentSource = source;
  90                 for (Filter filter : filters) {
  91                         filter.open(currentMetadata);
  92                         currentMetadata = filter.metadata();
  93                         Connection connection = new Connection(currentSource, Arrays.asList(filter));
  94                         filterConnections.put(filter, connection);
  95                         String threadName = String.format("%s → %s", connection.source().name(), filter.name());
  96                         logger.info(String.format("Starting Thread: %s.", threadName));
  97                         new Thread(connection, threadName).start();
  98                         currentSource = filter;
  99                 }
 100                 metadataUpdated(currentMetadata);
 101         }
 102
 103         @Override
 104         public DataPacket get(int bufferSize) throws IOException {
 105                 if (filterConnections.get(lastFilter).ioException().isPresent()) {
 106                         logger.info(String.format("Rethrowing exception from %s: %s", lastFilter.name(), filterConnections.get(lastFilter).ioException().get().getMessage()));
 107                         throw filterConnections.get(lastFilter).ioException().get();
 108                 }
 109                 logger.info(String.format("Requesting %d bytes from %s...", bufferSize, lastFilter.name()));
 110                 return lastFilter.get(bufferSize);
 111         }
 112
 113         @Override
 114         public void process(DataPacket dataPacket) throws IOException {
 115                 source.process(dataPacket);
 116         }
 117
 118         //
 119         // STATIC METHODS
 120         //
 121
 122         /**
 123          * Returns a builder that can create pipeline filters.
 124          *
 125          * @param source
 126          *              The source filter of the pipeline
 127          * @return The pipeline filter builder
 128          */
 129         public static Builder builder(Filter source) {
 130                 return new Builder(source);
 131         }
 132
 133         /**
 134          * Builder for a {@link PipelineFilter}.
 135          *
 136          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 137          */
 138         public static class Builder {
 139
 140                 /** The source of the pipeline. */
 141                 private final Filter source;
 142
 143                 /** All other filters of the pipeline. */
 144                 private final List<Filter> filters = Lists.newArrayList();
 145
 146                 /**
 147                  * Creates a new builder with the given source.
 148                  *
 149                  * @param source
 150                  *              The source of the pipeline filter
 151                  */
 152                 private Builder(Filter source) {
 153                         this.source = source;
 154                 }
 155
 156                 /**
 157                  * Connects the given filter at the end of the pipeline being build.
 158                  *
 159                  * @param filter
 160                  *              The filter to add
 161                  * @return This builder
 162                  */
 163                 public Builder to(Filter filter) {
 164                         filters.add(filter);
 165                         return this;
 166                 }
 167
 168                 /**
 169                  * Builds a filter using the given name. If no filters other than the source
 170                  * have been added, only the source filter is being returned.
 171                  *
 172                  * @param name
 173                  *              The name of the pipeline filter to build
 174                  * @return The created filter, or the source filter
 175                  */
 176                 public Filter build(String name) {
 177                         if (filters.isEmpty()) {
 178                                 return source;
 179                         }
 180                         return new PipelineFilter(name, source, filters);
 181                 }
 182
 183         }
 184
 185 }