Implement position filtering (fix #259)

1 files changed, 133 insertions, 0 deletions

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;
+    }
+
+}