/*
* 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 org.apache.brooklyn.core.sensor;
import org.apache.brooklyn.api.entity.EntityLocal;
import org.apache.brooklyn.api.mgmt.Task;
import org.apache.brooklyn.config.ConfigKey;
import org.apache.brooklyn.core.config.ConfigKeys;
import org.apache.brooklyn.core.effector.AddSensor;
import org.apache.brooklyn.enricher.stock.Propagator;
import org.apache.brooklyn.util.core.config.ConfigBag;
import org.apache.brooklyn.util.core.task.Tasks;
import org.apache.brooklyn.util.core.task.ValueResolver;
import org.apache.brooklyn.util.guava.Maybe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Supplier;
/**
* Provides an initializer/feed which simply sets a given value.
* <p>
* {@link Task}/{@link Supplier} values are resolved when written,
* unlike config values which are resolved on each read.
* <p>
* This supports a {@link StaticSensor#SENSOR_PERIOD}
* which can be useful if the supplied value is such a function.
* However when the source is another sensor,
* consider using {@link Propagator} which listens for changes instead. */
public class StaticSensor<T> extends AddSensor<T> {
private static final Logger log = LoggerFactory.getLogger(StaticSensor.class);
public static final ConfigKey<Object> STATIC_VALUE = ConfigKeys.newConfigKey(Object.class, "static.value");
private final Object value;
public StaticSensor(ConfigBag params) {
super(params);
value = params.get(STATIC_VALUE);
}
@SuppressWarnings("unchecked")
@Override
public void apply(EntityLocal entity) {
super.apply(entity);
Maybe<T> v = Tasks.resolving(value).as((Class<T>)sensor.getType()).timeout(ValueResolver.PRETTY_QUICK_WAIT).getMaybe();
if (v.isPresent()) {
log.debug(this+" setting sensor "+sensor+" to "+v.get());
entity.sensors().set(sensor, v.get());
} else {
log.debug(this+" not setting sensor "+sensor+"; cannot resolve "+value);
}
}
}