com.esri.geoevent.solutions.processor.updateOnly.UpdateOnlyProcessor.java Source code

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Here is the source code for com.esri.geoevent.solutions.processor.updateOnly.UpdateOnlyProcessor.java

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/*
 | Copyright 2014 Esri
 |
 | 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 com.esri.geoevent.solutions.processor.updateOnly;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.esri.ges.core.component.ComponentException;
import com.esri.ges.core.geoevent.GeoEvent;
import com.esri.ges.core.property.Property;
import com.esri.ges.processor.GeoEventProcessorBase;
import com.esri.ges.processor.GeoEventProcessorDefinition;

public class UpdateOnlyProcessor extends GeoEventProcessorBase {
    // This class attempts to reduce the volume of output geoevents by filtering out events that have no updates
    // (i.e. the TIME_START tagged field is no later than last time a TRACK_ID was processed)
    // Use of this processor requires that incoming geoevent definitions has TRACK_ID and TIME_START tags applied to their fields

    protected static String CLEAR_CACHE_PROPERTY_NAME = "ClearCache";
    private static final Log LOG = LogFactory.getLog(UpdateOnlyProcessor.class);
    private Map<String, Date> trackCache = new HashMap<String, Date>();

    protected UpdateOnlyProcessor(GeoEventProcessorDefinition definition) throws ComponentException {
        super(definition);
    }

    @Override
    public GeoEvent process(GeoEvent geoEvent) throws Exception {
        String trackID = geoEvent.getTrackId();
        Date startTime = geoEvent.getStartTime();
        if (trackCache.containsKey(trackID)) {
            Date lastTime = trackCache.get(trackID);
            // Filter out any tracks that haven't been updated since last time
            if (!startTime.after(lastTime)) {
                LOG.trace("UpdateOnlyProcessor ignoring track as nothing new since last time: " + trackID + " : "
                        + startTime.toString());
                return null;
            }
            LOG.trace("UpdateOnlyProcessor is handling new data for track " + trackID + " : " + startTime.toString()
                    + " is more recent than " + lastTime.toString());
        } else {
            LOG.trace("UpdateOnlyProcessor is handling a new track: " + trackID + " : " + startTime.toString());
        }
        // If we've reached here, then either there's an update to a track in the cache, or there's a new track, so record it in the cache
        trackCache.put(trackID, startTime);
        //... and allow the geoEvent through
        return geoEvent;
    }

    @Override
    public void afterPropertiesSet() {
        // If a user sets the "Clear Cache" property, then clear it, and un-set the property again
        // Users might want to clear the cache when another element later in the process chain has broken, or the outbound connector failed,
        // ... as this could mean the cache has a record of updates that never reached their final destination
        Boolean propValue = (Boolean) getProperty(CLEAR_CACHE_PROPERTY_NAME).getValue();
        if (propValue) {
            trackCache.clear();
            LOG.info(
                    "UpdateOnlyProcessor cache was cleared by user setting the Clear Cache property. Resetting to false...");
            getProperty(CLEAR_CACHE_PROPERTY_NAME).setValue(false);
        }
        super.afterPropertiesSet();
    }

    @Override
    public String toString() {
        StringBuffer sb = new StringBuffer();
        sb.append(definition.getName());
        sb.append("/");
        sb.append(definition.getVersion());
        sb.append("[");
        for (Property p : getProperties()) {
            sb.append(p.getDefinition().getPropertyName());
            sb.append(":");
            sb.append(p.getValue());
            sb.append(" ");
        }
        sb.append("]");
        return sb.toString();
    }
}