From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Wed, 5 Jun 2013 05:05:54 +0000 (+0200)
Subject: Add filter that combines several filters into one.
X-Git-Url: https://git.pterodactylus.net/?p=sonitus.git;a=commitdiff_plain;h=49a2e3007f3fde4fc339ed29bfe54eeb27eba671

Add filter that combines several filters into one.
---

diff --git a/src/main/java/net/pterodactylus/sonitus/data/filter/PipelineFilter.java b/src/main/java/net/pterodactylus/sonitus/data/filter/PipelineFilter.java
new file mode 100644
index 0000000..59e34be
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/data/filter/PipelineFilter.java
@@ -0,0 +1,176 @@
+/*
+ * Sonitus - PipelineFilter.java - Copyright © 2013 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.sonitus.data.filter;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+import net.pterodactylus.sonitus.data.AbstractFilter;
+import net.pterodactylus.sonitus.data.DataPacket;
+import net.pterodactylus.sonitus.data.Filter;
+import net.pterodactylus.sonitus.data.Metadata;
+import net.pterodactylus.sonitus.data.Pipeline.Connection;
+
+import com.google.common.base.Function;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.Lists;
+
+/**
+ * {@link Filter} that combines several filters into one.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class PipelineFilter extends AbstractFilter implements Filter {
+
+	/** The first filter. */
+	private final Filter source;
+
+	/** All following filters. */
+	private final List<Filter> filters = Lists.newArrayList();
+
+	/** The last filter (for convenience). */
+	private final Filter lastFilter;
+
+	/**
+	 * Creates a new pipeline filter.
+	 *
+	 * @param name
+	 * 		The name of the filter
+	 * @param source
+	 * 		The first source of the filter
+	 * @param filters
+	 * 		All other filters in correct order
+	 */
+	private PipelineFilter(String name, Filter source, Collection<Filter> filters) {
+		super(name);
+		this.source = source;
+		this.filters.addAll(filters);
+		this.lastFilter = this.filters.get(filters.size() - 1);
+	}
+
+	//
+	// FILTER METHODS
+	//
+
+	@Override
+	public Metadata metadata() {
+		return lastFilter.metadata();
+	}
+
+	@Override
+	public void open(Metadata metadata) throws IOException {
+		/* open the source and all filters in the correct order. */
+		source.open(metadata);
+		Metadata currentMetadata = source.metadata();
+		Filter currentSource = source;
+		for (Filter filter : filters) {
+			filter.open(currentMetadata);
+			currentMetadata = filter.metadata();
+			Connection connection = new Connection(currentSource, Arrays.asList(filter));
+			String threadName = String.format("%s → %s.", connection.source().name(), FluentIterable.from(connection.sinks()).transform(new Function<Filter, String>() {
+
+				@Override
+				public String apply(Filter sink) {
+					return sink.name();
+				}
+			}));
+			new Thread(connection, threadName).start();
+			currentSource = filter;
+		}
+	}
+
+	@Override
+	public DataPacket get(int bufferSize) throws IOException {
+		return lastFilter.get(bufferSize);
+	}
+
+	@Override
+	public void process(DataPacket dataPacket) throws IOException {
+		source.process(dataPacket);
+	}
+
+	//
+	// STATIC METHODS
+	//
+
+	/**
+	 * Returns a builder that can create pipeline filters.
+	 *
+	 * @param source
+	 * 		The source filter of the pipeline
+	 * @return The pipeline filter builder
+	 */
+	public static Builder builder(Filter source) {
+		return new Builder(source);
+	}
+
+	/**
+	 * Builder for a {@link PipelineFilter}.
+	 *
+	 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+	 */
+	public static class Builder {
+
+		/** The source of the pipeline. */
+		private final Filter source;
+
+		/** All other filters of the pipeline. */
+		private final List<Filter> filters = Lists.newArrayList();
+
+		/**
+		 * Creates a new builder with the given source.
+		 *
+		 * @param source
+		 * 		The source of the pipeline filter
+		 */
+		private Builder(Filter source) {
+			this.source = source;
+		}
+
+		/**
+		 * Connects the given filter at the end of the pipeline being build.
+		 *
+		 * @param filter
+		 * 		The filter to add
+		 * @return This builder
+		 */
+		public Builder to(Filter filter) {
+			filters.add(filter);
+			return this;
+		}
+
+		/**
+		 * Builds a filter using the given name. If no filters other than the source
+		 * have been added, only the source filter is being returned.
+		 *
+		 * @param name
+		 * 		The name of the pipeline filter to build
+		 * @return The created filter, or the source filter
+		 */
+		public Filter build(String name) {
+			if (filters.isEmpty()) {
+				return source;
+			}
+			return new PipelineFilter(name, source, filters);
+		}
+
+	}
+
+}