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