Implement position filtering (fix #259)

3 files changed, 181 insertions, 7 deletions

diff --git a/src/org/traccar/BasePipelineFactory.java b/src/org/traccar/BasePipelineFactory.java
index d7fcfe28a..e1f1e10e5 100644
--- a/src/org/traccar/BasePipelineFactory.java
+++ b/src/org/traccar/BasePipelineFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 - 2013 Anton Tananaev (anton.tananaev@gmail.com)
+ * Copyright 2012 - 2014 Anton Tananaev (anton.tananaev@gmail.com)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
  */
 package org.traccar;
 
-import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBuffers;
@@ -31,18 +30,19 @@ import org.traccar.model.DataManager;
   */
 public abstract class BasePipelineFactory implements ChannelPipelineFactory {
 
-    private TrackerServer server;
-    private DataManager dataManager;
-    private Boolean loggerEnabled;
+    private final TrackerServer server;
+    private final DataManager dataManager;
+    private final Boolean loggerEnabled;
+    private final ReverseGeocoder reverseGeocoder;
+    private FilterHandler filterHandler;
     private Integer resetDelay;
-    private ReverseGeocoder reverseGeocoder;
 
     /**
      * Open channel handler
      */
     protected class OpenChannelHandler extends SimpleChannelHandler {
 
-        private TrackerServer server;
+        private final TrackerServer server;
 
         public OpenChannelHandler(TrackerServer server) {
             this.server = server;
@@ -95,6 +95,11 @@ public abstract class BasePipelineFactory implements ChannelPipelineFactory {
         if (resetDelayProperty != null) {
             resetDelay = Integer.valueOf(resetDelayProperty);
         }
+
+        String enableFilter = serverManager.getProperties().getProperty("filter.enable");
+        if (enableFilter != null && Boolean.valueOf(enableFilter)) {
+            filterHandler = new FilterHandler(serverManager);
+        }
     }
 
     protected DataManager getDataManager() {
@@ -114,6 +119,9 @@ public abstract class BasePipelineFactory implements ChannelPipelineFactory {
             pipeline.addLast("logger", new StandardLoggingHandler());
         }
         addSpecificHandlers(pipeline);
+        if (filterHandler != null) {
+            pipeline.addLast("filter", filterHandler);
+        }
         if (reverseGeocoder != null) {
             pipeline.addLast("geocoder", new ReverseGeocoderHandler(reverseGeocoder));
         }
diff --git a/src/org/traccar/FilterHandler.java b/src/org/traccar/FilterHandler.java
new file mode 100644
index 000000000..18ae2ecae
--- /dev/null
+++ b/src/org/traccar/FilterHandler.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright 2014 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.handler.codec.oneone.OneToOneDecoder;
+import org.traccar.helper.DistanceCalculator;
+import org.traccar.helper.Log;
+import org.traccar.model.Position;
+
+public class FilterHandler extends OneToOneDecoder {
+
+    private boolean filterInvalid;
+    private boolean filterZero;
+    private boolean filterDuplicate;
+    private int filterDistance;
+    
+    private final Map<Long, Position> lastPositions = new HashMap<Long, Position>();
+    
+    public FilterHandler(ServerManager serverManager) {
+        Properties properties = serverManager.getProperties();
+
+        String value = properties.getProperty("filter.invalid");
+        if (value != null) filterInvalid = Boolean.valueOf(value);
+
+        value = properties.getProperty("filter.zero");
+        if (value != null) filterZero = Boolean.valueOf(value);
+
+        value = properties.getProperty("filter.duplicate");
+        if (value != null) filterDuplicate = Boolean.valueOf(value);
+
+        value = properties.getProperty("filter.distance");
+        if (value != null) filterDistance = Integer.valueOf(value);
+    }
+    
+    private boolean filterInvalid(Position position) {
+        return filterInvalid && !position.getValid();
+    }
+    
+    private boolean filterZero(Position position) {
+        return filterZero &&
+                (position.getLatitude() == 0.0) &&
+                (position.getLongitude() == 0.0);
+    }
+    
+    private boolean filterDuplicate(Position position) {
+        if (filterDuplicate) {
+            Position last = lastPositions.get(position.getDeviceId());
+            if (last != null) {
+                return position.getTime().equals(last.getTime());
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+    
+    private boolean filterDistance(Position position) {
+        if (filterDistance != 0) {
+            Position last = lastPositions.get(position.getDeviceId());
+            if (last != null) {
+                double distance = DistanceCalculator.distance(
+                        position.getLatitude(), position.getLongitude(),
+                        last.getLatitude(), last.getLongitude());
+                return distance < filterDistance;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+    
+    private boolean filter(Position p) {
+        
+        boolean result =
+                filterInvalid(p) ||
+                filterZero(p) ||
+                filterDuplicate(p) ||
+                filterDistance(p);
+        
+        if (!result) {
+            lastPositions.put(p.getDeviceId(), p);
+        } else {
+            StringBuilder s = new StringBuilder();
+            Log.info("Position filtered from " + p.getDeviceId());
+        }
+
+        return result;
+    }
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, Object msg)
+            throws Exception {
+        
+        if (msg instanceof Position) {
+            if (filter((Position) msg)) {
+                return null;
+            }
+        } else if (msg instanceof List) {
+            Iterator<Position> i = ((List<Position>) msg).iterator();
+            while (i.hasNext()) {
+               if (filter(i.next())) {
+                   i.remove();
+               }
+            }
+        }
+
+        return msg;
+    }
+
+}
diff --git a/src/org/traccar/helper/DistanceCalculator.java b/src/org/traccar/helper/DistanceCalculator.java
new file mode 100644
index 000000000..072f3d7a8
--- /dev/null
+++ b/src/org/traccar/helper/DistanceCalculator.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2014 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.helper;
+
+public class DistanceCalculator {
+
+    private static final double equatorialEarthRadius = 6378.1370D;
+    private static final double deg2rad = (Math.PI / 180);
+
+    public static double distance(double lat1, double lon1, double lat2, double lon2) {
+        double dlong = (lon2 - lon1) * deg2rad;
+        double dlat = (lat2 - lat1) * deg2rad;
+        double a = Math.pow(Math.sin(dlat / 2), 2) +
+                Math.cos(lat1 * deg2rad) * Math.cos(lat2 * deg2rad) * Math.pow(Math.sin(dlong / 2), 2);
+        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+        double d = equatorialEarthRadius * c;
+        return d * 1000;
+    }
+
+}