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