001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.monitoring.gauges;
018    
019    import org.apache.commons.monitoring.Role;
020    import org.apache.commons.monitoring.store.DataStore;
021    
022    import java.util.Map;
023    import java.util.Timer;
024    import java.util.TimerTask;
025    import java.util.concurrent.ConcurrentHashMap;
026    
027    public final class DefaultGaugeManager implements GaugeManager {
028        private final Map<Role, Timer> timers = new ConcurrentHashMap<Role, Timer>();
029        private final DataStore store;
030    
031        public DefaultGaugeManager(final DataStore dataStore) {
032            store = dataStore;
033        }
034    
035        @Override
036        public void stop() {
037            for (final Timer timer : timers.values()) {
038                timer.cancel();
039            }
040            timers.clear();
041        }
042    
043        @Override
044        public void stopGauge(final Role role) {
045            final Timer timer = timers.remove(role);
046            if (timer != null) {
047                timer.cancel();
048            }
049        }
050    
051        @Override
052        public void addGauge(final Gauge gauge) {
053            final Role role = gauge.role();
054    
055            this.store.createOrNoopGauge(role);
056    
057            final Timer timer = new Timer("gauge-" + role.getName() + "-timer", true);
058            timers.put(role, timer);
059            timer.scheduleAtFixedRate(new GaugeTask(store, gauge), 0, gauge.period());
060        }
061    
062        private static class GaugeTask extends TimerTask {
063            private final Gauge gauge;
064            private final DataStore store;
065    
066            public GaugeTask(final DataStore store, final Gauge gauge) {
067                this.store = store;
068                this.gauge = gauge;
069            }
070    
071            @Override
072            public void run() {
073                store.addToGauge(gauge, System.currentTimeMillis(), gauge.value());
074            }
075        }
076    }