com.buddycloud.channeldirectory.search.handler.nearby.NearbyQueryHandler.java Source code

Introduction

Here is the source code for com.buddycloud.channeldirectory.search.handler.nearby.NearbyQueryHandler.java

Source

/*
 * Copyright 2011 buddycloud
 *
 * 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.buddycloud.channeldirectory.search.handler.nearby;

import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import org.apache.solr.client.solrj.SolrQuery;
import org.apache.solr.client.solrj.SolrQuery.ORDER;
import org.apache.solr.client.solrj.SolrServer;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrDocumentList;
import org.dom4j.Attribute;
import org.dom4j.Element;
import org.xmpp.packet.IQ;

import com.buddycloud.channeldirectory.commons.solr.SolrServerFactory;
import com.buddycloud.channeldirectory.search.handler.common.ChannelQueryHandler;
import com.buddycloud.channeldirectory.search.handler.response.ChannelData;
import com.buddycloud.channeldirectory.search.handler.response.Geolocation;
import com.buddycloud.channeldirectory.search.rsm.RSM;
import com.buddycloud.channeldirectory.search.rsm.RSMUtils;
import com.buddycloud.channeldirectory.search.rsm.SolrRSMUtils;
import com.buddycloud.channeldirectory.search.utils.XMPPUtils;

/**
 * Handles queries for nearby content.
 * A query should contain user's lat/lon pair, so
 * this handle can return channels close to user location.
 * Returns the closest channels (in ascending distance order)
 * in a 1000km radius.
 */
public class NearbyQueryHandler extends ChannelQueryHandler {

    private static final String RADIUS_IN_KM = "1000";

    public NearbyQueryHandler(Properties properties) {
        super("http://buddycloud.com/channel_directory/nearby_query", properties);
    }

    @Override
    public IQ handle(IQ iq) {

        Element queryElement = iq.getElement().element("query");
        Element pointElement = queryElement.element("point");

        if (pointElement == null) {
            return XMPPUtils.error(iq, "Query does not contain point element.", getLogger());
        }

        Attribute latAtt = pointElement.attribute("lat");
        if (latAtt == null) {
            return XMPPUtils.error(iq, "Location point does not contain point latitude element.", getLogger());
        }

        Attribute lngAtt = pointElement.attribute("lon");
        if (lngAtt == null) {
            return XMPPUtils.error(iq, "Location point does not contain point longitude element.", getLogger());
        }

        double lat = Double.valueOf(latAtt.getValue());
        double lng = Double.valueOf(lngAtt.getValue());

        RSM rsm = RSMUtils.parseRSM(queryElement);
        List<ChannelData> nearbyObjects;

        try {
            nearbyObjects = findNearbyObjects(lat, lng, rsm);
        } catch (Exception e) {
            return XMPPUtils.error(iq, "Search could not be performed, service is unavailable.", getLogger());
        }

        return createIQResponse(iq, nearbyObjects, rsm);
    }

    private List<ChannelData> findNearbyObjects(double lat, double lng, RSM rsm)
            throws MalformedURLException, SolrServerException {
        SolrServer solrServer = SolrServerFactory.createChannelCore(getProperties());
        SolrQuery solrQuery = new SolrQuery("*:*");
        solrQuery.set("fq", "{!geofilt}");
        solrQuery.set("sfield", "geoloc");
        solrQuery.set("pt", lat + "," + lng);
        solrQuery.set("d", RADIUS_IN_KM);

        solrQuery.addSortField("geodist()", ORDER.asc);

        SolrRSMUtils.preprocess(solrQuery, rsm);
        QueryResponse queryResponse = solrServer.query(solrQuery);
        SolrRSMUtils.postprocess(queryResponse, rsm);

        return convertResponse(queryResponse);
    }

    private static List<ChannelData> convertResponse(QueryResponse queryResponse) {
        List<ChannelData> channels = new ArrayList<ChannelData>();
        SolrDocumentList results = queryResponse.getResults();

        for (SolrDocument solrDocument : results) {
            channels.add(convertDocument(solrDocument));
        }

        return channels;
    }

    private static ChannelData convertDocument(SolrDocument solrDocument) {
        ChannelData channelData = new ChannelData();
        String latLonStr = (String) solrDocument.getFieldValue("geoloc");
        if (latLonStr != null) {
            String[] latLonSplit = latLonStr.split(",");
            channelData.setGeolocation(
                    new Geolocation(Double.parseDouble(latLonSplit[0]), Double.parseDouble(latLonSplit[1])));
        }

        channelData.setId((String) solrDocument.getFieldValue("jid"));
        channelData.setTitle((String) solrDocument.getFieldValue("title"));
        return channelData;
    }

}