1 files changed, 129 insertions, 0 deletions
diff --git a/src/org/traccar/handler/ComputedAttributesHandler.java b/src/org/traccar/handler/ComputedAttributesHandler.java
new file mode 100644
index 000000000..4b5b8c20d
--- /dev/null
+++ b/src/org/traccar/handler/ComputedAttributesHandler.java
@@ -0,0 +1,129 @@
+/*
+ * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 Andrey Kunitsyn (andrey@traccar.org)
+ *
+ * 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.handler;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import io.netty.channel.ChannelHandler;
+import org.apache.commons.jexl2.JexlEngine;
+import org.apache.commons.jexl2.JexlException;
+import org.apache.commons.jexl2.MapContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.traccar.BaseDataHandler;
+import org.traccar.Context;
+import org.traccar.model.Attribute;
+import org.traccar.model.Device;
+import org.traccar.model.Position;
+
+@ChannelHandler.Sharable
+public class ComputedAttributesHandler extends BaseDataHandler {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ComputedAttributesHandler.class);
+
+    private JexlEngine engine;
+
+    private boolean mapDeviceAttributes;
+
+    public ComputedAttributesHandler() {
+        engine = new JexlEngine();
+        engine.setStrict(true);
+        engine.setFunctions(Collections.singletonMap("math", (Object) Math.class));
+        if (Context.getConfig() != null) {
+            mapDeviceAttributes = Context.getConfig().getBoolean("handler.computedAttributes.deviceAttributes");
+        }
+    }
+
+    private MapContext prepareContext(Position position) {
+        MapContext result = new MapContext();
+        if (mapDeviceAttributes) {
+            Device device = Context.getIdentityManager().getById(position.getDeviceId());
+            if (device != null) {
+                for (Object key : device.getAttributes().keySet()) {
+                    result.set((String) key, device.getAttributes().get(key));
+                }
+            }
+        }
+        Set<Method> methods = new HashSet<>(Arrays.asList(position.getClass().getMethods()));
+        methods.removeAll(Arrays.asList(Object.class.getMethods()));
+        for (Method method : methods) {
+            if (method.getName().startsWith("get") && method.getParameterTypes().length == 0) {
+                String name = Character.toLowerCase(method.getName().charAt(3)) + method.getName().substring(4);
+
+                try {
+                    if (!method.getReturnType().equals(Map.class)) {
+                        result.set(name, method.invoke(position));
+                    } else {
+                        for (Object key : ((Map) method.invoke(position)).keySet()) {
+                            result.set((String) key, ((Map) method.invoke(position)).get(key));
+                        }
+                    }
+                } catch (IllegalAccessException | InvocationTargetException error) {
+                    LOGGER.warn("Attribute reflection error", error);
+                }
+            }
+        }
+        return result;
+    }
+
+    public Object computeAttribute(Attribute attribute, Position position) throws JexlException {
+        return engine.createExpression(attribute.getExpression()).evaluate(prepareContext(position));
+    }
+
+    @Override
+    protected Position handlePosition(Position position) {
+        Collection<Attribute> attributes = Context.getAttributesManager().getItems(
+                Context.getAttributesManager().getAllDeviceItems(position.getDeviceId()));
+        for (Attribute attribute : attributes) {
+            if (attribute.getAttribute() != null) {
+                Object result = null;
+                try {
+                    result = computeAttribute(attribute, position);
+                } catch (JexlException error) {
+                    LOGGER.warn("Attribute computation error", error);
+                }
+                if (result != null) {
+                    try {
+                        switch (attribute.getType()) {
+                            case "number":
+                                Number numberValue = (Number) result;
+                                position.getAttributes().put(attribute.getAttribute(), numberValue);
+                                break;
+                            case "boolean":
+                                Boolean booleanValue = (Boolean) result;
+                                position.getAttributes().put(attribute.getAttribute(), booleanValue);
+                                break;
+                            default:
+                                position.getAttributes().put(attribute.getAttribute(), result.toString());
+                        }
+                    } catch (ClassCastException error) {
+                        LOGGER.warn("Attribute cast error", error);
+                    }
+                }
+            }
+        }
+        return position;
+    }
+
+}