Github user neykov commented on a diff in the pull request:
https://github.com/apache/incubator-brooklyn/pull/131#discussion_r16893810
--- Diff: core/src/main/java/brooklyn/enricher/basic/UpdatingMap.java ---
@@ -0,0 +1,160 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 brooklyn.enricher.basic;
+
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import brooklyn.config.ConfigKey;
+import brooklyn.entity.basic.ConfigKeys;
+import brooklyn.entity.basic.Entities;
+import brooklyn.entity.basic.EntityLocal;
+import brooklyn.event.AttributeSensor;
+import brooklyn.event.Sensor;
+import brooklyn.event.SensorEvent;
+import brooklyn.event.SensorEventListener;
+import brooklyn.util.collections.MutableMap;
+import brooklyn.util.exceptions.Exceptions;
+import brooklyn.util.flags.SetFromFlag;
+
+import com.google.common.base.Function;
+import com.google.common.collect.Maps;
+import com.google.common.reflect.TypeToken;
+
+/**
+ * Enricher which updates an entry in a sensor map ({@link
#TARGET_SENSOR})
+ * based on the value of another sensor ({@link #SOURCE_SENSOR}.
+ * <p>
+ * The key used defaults to the name of the source sensor but can be
specified with {@link #KEY_IN_TARGET_SENSOR}.
+ * The value placed in the map is the result of applying the function in
{@link #COMPUTING} to the sensor value,
+ * with default behaviour being to remove an entry if <code>null</code> is
returned
+ * but this can be overriden by setting {@link
#REMOVING_IF_RESULT_IS_NULL} false.
+ * {@link Entities#REMOVE} and {@link Entities#UNCHANGED} are also
respeced as return values for the computation
+ * (ignoring generics).
+ * Unlike most other enrichers, this defaults to {@link
AbstractEnricher#SUPPRESS_DUPLICATES} being true
+ *
+ * @author alex
+ *
+ * @param <S> source sensor type
+ * @param <TKey> key type in target sensor map
+ * @param <TVal> value type in target sensor map
+ */
+@SuppressWarnings("serial")
+public class UpdatingMap<S,TKey,TVal> extends AbstractEnricher implements
SensorEventListener<S> {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(UpdatingMap.class);
+
+ @SetFromFlag("fromSensor")
+ public static final ConfigKey<Sensor<?>> SOURCE_SENSOR =
ConfigKeys.newConfigKey(new TypeToken<Sensor<?>>() {}, "enricher.sourceSensor");
+ @SetFromFlag("targetSensor")
+ public static final ConfigKey<Sensor<?>> TARGET_SENSOR =
ConfigKeys.newConfigKey(new TypeToken<Sensor<?>>() {}, "enricher.targetSensor");
+ @SetFromFlag("key")
+ public static final ConfigKey<?> KEY_IN_TARGET_SENSOR =
ConfigKeys.newConfigKey(Object.class, "enricher.updatingMap.keyInTargetSensor",
+ "Key to update in the target sensor map, defaulting to the name of
the source sensor");
+ @SetFromFlag("computing")
+ public static final ConfigKey<Function<?, ?>> COMPUTING =
ConfigKeys.newConfigKey(new TypeToken<Function<?,?>>() {},
"enricher.updatingMap.computing");
+ @SetFromFlag("removingIfResultIsNull")
+ public static final ConfigKey<Boolean> REMOVING_IF_RESULT_IS_NULL =
ConfigKeys.newBooleanConfigKey("enricher.updatingMap.removingIfResultIsNull",
+ "Whether the key in the target map is removed if the result if the
computation is null");
+
+ protected AttributeSensor<S> sourceSensor;
+ protected AttributeSensor<Map<TKey,TVal>> targetSensor;
+ protected TKey key;
+ protected Function<S,? extends TVal> computing;
+ protected Boolean removingIfResultIsNull;
+
+ public UpdatingMap() {
+ this(Maps.newLinkedHashMap());
+ }
+
+ public UpdatingMap(Map<Object, Object> flags) {
+ super(flags);
+ if (suppressDuplicates==null) {
+ // this defaults to suppressing duplicates
+ suppressDuplicates = true;
+ }
+ }
+
+ @SuppressWarnings({ "unchecked", "rawtypes" })
+ @Override
+ public void setEntity(EntityLocal entity) {
+ super.setEntity(entity);
+ this.sourceSensor = (AttributeSensor<S>)
getRequiredConfig(SOURCE_SENSOR);
+ this.targetSensor = (AttributeSensor<Map<TKey,TVal>>)
getRequiredConfig(TARGET_SENSOR);
+ this.key = (TKey) getConfig(KEY_IN_TARGET_SENSOR);
+ this.computing = (Function) getRequiredConfig(COMPUTING);
+ this.removingIfResultIsNull =
getConfig(REMOVING_IF_RESULT_IS_NULL);
+
+ subscribe(entity, sourceSensor, this);
+ onUpdated();
+ }
+
+ @Override
+ public void onEvent(SensorEvent<S> event) {
+ onUpdated();
+ }
+
+ /**
+ * Called whenever the values for the set of producers changes (e.g.
on an event, or on a member added/removed).
+ */
+ @SuppressWarnings("unchecked")
+ protected void onUpdated() {
+ try {
+ Object v = computing.apply(entity.getAttribute(sourceSensor));
+ if (v == null &&
!Boolean.FALSE.equals(removingIfResultIsNull)) {
+ v = Entities.REMOVE;
+ }
+ if (v == Entities.UNCHANGED) {
+ // nothing
+ } else {
+ // TODO check synchronization
+ TKey key = this.key;
+ if (key==null) key = (TKey) sourceSensor.getName();
+
+ Map<TKey, TVal> map = entity.getAttribute(targetSensor);
+
+ boolean created = (map==null);
+ if (created) map = MutableMap.of();
+
+ boolean changed;
+ if (v == Entities.REMOVE) {
+ changed = map.containsKey(key);
+ if (changed)
+ map.remove(key);
+ } else {
+ TVal oldV = map.get(key);
+ if (oldV==null)
+ changed = (v!=null || !map.containsKey(key));
+ else
+ changed = !oldV.equals(v);
--- End diff --
"v" could be null, while equals doesn't guarantee it is null safe.
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