daoas/daoadresseservice/AddressSearch.java

package dk.daoas.daoadresseservice;

import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.lang3.StringUtils;

import dk.daoas.daoadresseservice.admin.ServiceConfig;
import dk.daoas.daoadresseservice.beans.Address;
import dk.daoas.daoadresseservice.beans.Address.RoutingInfo;
import dk.daoas.daoadresseservice.beans.AliasBean;
import dk.daoas.daoadresseservice.beans.DataStatisticsBean;
import dk.daoas.daoadresseservice.beans.ExtendedBean;
import dk.daoas.daoadresseservice.beans.HundredePctBean;
import dk.daoas.daoadresseservice.beans.SearchRequest;
import dk.daoas.daoadresseservice.beans.SearchResult;
import dk.daoas.daoadresseservice.beans.SearchResult.Status;
import dk.daoas.daoadresseservice.db.DatabaseLayer;
import dk.daoas.daoadresseservice.util.DaoUtils;
import dk.daoas.daoadresseservice.util.DeduplicateHelper;
import dk.daoas.daoadresseservice.util.NaturalOrderComparator;
import dk.daoas.daoadresseservice.util.NearestShortTreeMap;

public class AddressSearch {

        private Map<Short, Map<String,Integer>> searchPostnrVejnavnGadeid;      
        private Map<Integer,  Map<Short, List<Address>>> searchGadeidentAdresser; // Gadeident -> husnrumre -> litra
        
        private ArrayList<Address> ikkeDaekkedeAdresser = new ArrayList<Address>(60000);
        private ArrayList<Address> hundredePctAdresser = new ArrayList<Address>(120000);
        
        private Map<String,Integer> helperCache;
        
        private DataStatisticsBean stats = new DataStatisticsBean();
        
        private DatabaseLayer db;
        private ServiceConfig config;
        
        
        StreetnameHelper levenshteinHelper;
        StreetnameHelper metaphoneHelper;
        StreetnameHelper googleHelper;
        StreetnameHelper osmHelper;
        
        
        public AddressSearch(DatabaseLayer db, ServiceConfig config) {
                
                this.db = db;
                this.config = config;
                
                levenshteinHelper = new LevenshteinStreetnameHelper();
                metaphoneHelper = new DoubleMetaphoneStreetnameHelper(config);
                googleHelper = new GoogleStreetnameHelper( config );
                osmHelper = new OSMStreetnameHelper( config );
        }
        
        public Address getAddressSafe(int gadeid, short husnr, String litra)  throws Exception {
                
                Map<Short, List<Address>> gade = searchGadeidentAdresser.get(gadeid);
                
                if (gade == null) {
                        throw new Exception("GadeID ikke fundet");
                }
                
                List<Address> litraList = gade.get(husnr);
                
                Address addr = null;
                for(Address a : litraList) {
                        if (a.husnrbogstav.equals(litra) ) {
                                addr = a;
                                break;
                        }
                }
                
                if (addr == null) {
                        throw new Exception("Adresse ikke ikke fundet");
                }
                                
                return addr;
        }
        

        public SearchResult search(String postnrStr, String adresse)  {
                return search(postnrStr, adresse, false);
        }
        
        
        public SearchResult search(String postnrStr, String adresse, boolean naermesteHusnr)  {
                
                postnrStr = postnrStr.trim();
                adresse = adresse.trim();
                
                
                SearchRequest request = new SearchRequest();
                SearchResult result = new SearchResult();
                
                
                try {
                        request.postnr = Short.parseShort(postnrStr);
                } catch (Exception E) {
                        result.status = Status.ERROR_UNKNOWN_POSTAL;
                        return result;
                }               
                
                
                request.streetNames = searchPostnrVejnavnGadeid.get(request.postnr);                    
                
                if (request.streetNames == null) {
                        result.status = Status.ERROR_UNKNOWN_POSTAL;
                        return result;
                }
                
                
                result.splitResult = AddressUtils.splitAdresse(adresse);
                request.vejnavn = result.splitResult.vej;
                
                                                
                if (result.splitResult.husnr.length() == 0) {
                        result.status = Status.ERROR_MISSING_HOUSENUMBER;
                        return result;
                }
                
                result.vasketVejnavn = AddressUtils.vaskVejnavn( request.vejnavn );
                

                if (result.vasketVejnavn.indexOf("pakkebo") > -1 
                                || result.vasketVejnavn.indexOf("pakkepost") > -1
                                || result.vasketVejnavn.indexOf("postbo") > -1   // postbox/postboks
                                || result.vasketVejnavn.indexOf("døgnpost") > -1
                                || result.vasketVejnavn.indexOf("døgnbo") > -1 // døgnbox // døgnboks
                                || result.vasketVejnavn.equals("id") 
                                ) {
                        result.status = Status.ERROR_POSTBOX;
                        return result;                  
                }
                
                // LookupStreetname er en indkapsling af alm + levenstein + google + osm
                Integer gadeident = lookupStretname(request, result, true);
                
                
                /*
                 * Hvis der ikke er direkte hits, prøver vi at skære ord af vejnavn
                 *
                 * <strike>Denne sektion er MEGET experimental da den øger antallet af kald til google/OSM væsentligt</strike>*/
                if (gadeident == null) {
                        final int MAX_TRIES = 4;
                        
                        String vejnavnParts[] = request.vejnavn.split(" ");
                        
                        for (int i=1; i<=MAX_TRIES && i<vejnavnParts.length; i++) {
                                String subVejnavn = DaoUtils.joinHelper(vejnavnParts, i);
                                
                                request.vejnavn = subVejnavn;
                                result.vasketVejnavn = AddressUtils.vaskVejnavn( request.vejnavn );
                                
                                gadeident = lookupStretname(request, result, false);//prøv opslag MEN UDEN GOOGLE/OSM !!!
                                
                                //hvis vi fandt vejen ud fra substrengen
                                if (gadeident != null) { 
                                        break;
                                }                       
                                
                                //hvis vi ikke fandt kopierer vi vejnavn fra split igen
                                request.vejnavn = result.splitResult.vej;
                                result.vasketVejnavn = AddressUtils.vaskVejnavn( request.vejnavn );
                        }                       
                }
                

                if (gadeident == null) {                        
                        result.status = Status.ERROR_UNKNOWN_STREETNAME; 
                        return result;
                }
                
                result.gadeident = gadeident;
                
                
                Map<Short, List<Address>> gade = searchGadeidentAdresser.get(gadeident); 
                if (gade == null) { //Denne søgning må ikke fejle
                        result.status = Status.ERROR_INTERNAL; 
                        return result;                  
                }
                
                
                //Kunne evt klares med Iterables.get fra Guava/Collections
                Address firstAddress = gade.values().iterator().next().get(0); //Første husnr -> første litra
                result.vej = firstAddress.vejnavn;
                
                short husnrSearch = Short.parseShort(result.splitResult.husnr );                
                List<Address> litraList = gade.get(husnrSearch);
                

                if (litraList == null) { //Husnr ikke fundet
                        
                        if (naermesteHusnr) {
                                TreeMap<Short, List<Address>> gadeTreeMap = (TreeMap<Short, List<Address>>) gade;
                                result.anvendtHusnr = NearestShortTreeMap.getNearestKey(husnrSearch, gadeTreeMap);
                                
                                result.nearestHusnr = true;
                                litraList = gade.get(result.anvendtHusnr);
                                
                                
                        } else {
                                result.status = Status.ERROR_UNKNOWN_ADDRESSPOINT; 
                                return result;  
                        }
                }
                
                Address addr  = null;
                for(Address a : litraList) {
                        if ( a.husnrbogstav.equals( result.splitResult.litra ) ) {
                                addr = a;
                                break;
                        }
                }
                
                if (addr == null) { //litra ikke fundet
                        if (config.nearestLitra == true || naermesteHusnr == true) {
                                result.nearestLitra = true;
                                addr = litraList.get(0);                                
                        } else {
                                //husnr fundet men litra blev ikke fundet
                                result.status = Status.ERROR_UNKNOWN_ADDRESSPOINT; 
                                return result;  
                        }                       
                }
                
                result.address = addr;
                
                
                if ( StringUtils.equals(addr.distributor, "LUKKET") ) {                 
                        result.status = Status.STATUS_NOT_COVERED; //Skal vi have en special status til Lukkede adresser ?
                        return result;
                }                               
                
                if (addr.daekningsType == DaekningsType.DAEKNING_IKKEDAEKKET) {
                        result.status = Status.STATUS_NOT_COVERED; 
                        return result;
                }

                
                result.status = Status.STATUS_OK;

                return result;
        }


        private Integer lookupStretname(SearchRequest request, SearchResult result, boolean useExternal) {
                String helperSearchKey = "";
                
                Integer gadeident =  request.streetNames.get(result.vasketVejnavn);
                
                
                if ( gadeident == null) {
                        helperSearchKey = "" + request.postnr + "/" + result.vasketVejnavn;
                        gadeident = helperCache.get(helperSearchKey);
                }
                
                if (gadeident == null) {
                        String vej = levenshteinHelper.proposeStreetName(request, result);
                        if (vej != null) {
                                gadeident =  request.streetNames.get(vej);
                        }
                }
                
                if (gadeident == null) {
                        String vej = metaphoneHelper.proposeStreetName(request, result);
                        if (vej != null) {
                                gadeident =  request.streetNames.get(vej);
                        }
                }
                
                
                // Brug OpenStreetMap før vi prøver google
                // For google har en request limit, det har OSM ikke!
                if ( gadeident == null && useExternal) {
                        String vej = osmHelper.proposeStreetName(request, result);              
                        gadeident = helperWrapper(vej, request.streetNames, helperSearchKey);
                }
                
                if ( gadeident == null && useExternal) {
                        String vej = googleHelper.proposeStreetName(request, result);           
                        gadeident = helperWrapper(vej, request.streetNames, helperSearchKey);
                }
                return gadeident;
        }
        
        private Integer helperWrapper(String vej, Map<String,Integer> postnrVeje, String helperSearchKey) {
                if (vej == null)
                        return null;
                
                String vejVasket = AddressUtils.vaskVejnavn( vej );
                Integer gadeident =  postnrVeje.get(vejVasket);
                
                if (gadeident != null) {
                        helperCache.put(helperSearchKey, gadeident);
                }
                return gadeident;
                
        }
        
        public Map<String,Integer> getStretsByPostal(short zip) {
                return searchPostnrVejnavnGadeid.get(zip);
        }

        
        public void buildSearchStructures() throws SQLException{
                searchPostnrVejnavnGadeid = new HashMap<Short, Map<String,Integer>>();
                searchGadeidentAdresser = new HashMap<Integer,  Map<Short, List<Address>>>();
                helperCache = new ConcurrentHashMap<String,Integer>();
                
                // //////////////////////
                // Start stage1
                
                long start1 = System.currentTimeMillis();
                System.out.println("Build -- stage 1");
                
                List<Address> alleAdresser = db.getAllAdresses();
                
                
                /* Mapper mellem db Row ID og adresse noden - skal bruges i stage3*/
                Map<Integer,Address> idAddressMap = new HashMap<Integer,Address>( alleAdresser.size() );
                
                
                DeduplicateHelper<Short> shortHelper = new DeduplicateHelper<Short>();
                DeduplicateHelper<Integer> intHelper = new DeduplicateHelper<Integer>();
                
                AliasGenerator aliasGenerator = new AliasGenerator();
                
                ArrayList<ArrayList<Address>> litraListCache = new ArrayList<ArrayList<Address>>(); 
                
                for (Address a : alleAdresser) {
                        idAddressMap.put(a.id, a);
                        
                        Short postnr = shortHelper.getInstance(a.postnr);
                        
                        Map<String,Integer> postnrVeje = searchPostnrVejnavnGadeid.get(postnr);         
                        
                        if (postnrVeje == null) {
                                postnrVeje = new HashMap<String,Integer>(10240); //lige nu indeholder den største 9500 entries
                                searchPostnrVejnavnGadeid.put(postnr, postnrVeje);
                        }
                                
                        
                        String vasketVejnavn = AddressUtils.vaskVejnavn(a.vejnavn);
                        Integer gadeident = postnrVeje.get(vasketVejnavn);
                        if (gadeident == null) {                                
                                //postnrVeje.put(vasketVejnavn, a.gadeid);
                                
                                gadeident = intHelper.getInstance( a.gadeid );
                                
                                Set<String> aliaser = aliasGenerator.findVejAliaser(a.vejnavn);
                                for(String alias : aliaser) {                                   
                                        postnrVeje.put(alias, gadeident);       
                                }
                                
                        }
                        
                        
                        Map<Short, List<Address>> gade =  searchGadeidentAdresser.get(gadeident); 
                        if (gade == null) {
                                gade = new TreeMap<Short, List<Address> >();
                                searchGadeidentAdresser.put(gadeident, gade);
                        }
                        
                        List<Address> litraList = gade.get(a.husnr);
                        if (litraList == null) {
                                litraList = new ArrayList<Address>();
                                gade.put(a.husnr, litraList);
                                
                                litraListCache.add( (ArrayList<Address>) litraList);
                        }
                        litraList.add(a);                       
                }
                
                for (ArrayList<Address> list: litraListCache) {
                        list.trimToSize();
                }
                
                
                litraListCache.clear(); //frigiv hukommelse inden stage2
                aliasGenerator.clear();  
                shortHelper.clear();
                intHelper.clear();
                                

                ////////////////////////////////////////////////////////////////////////////////////////
                long start2 = System.currentTimeMillis();
                System.out.println("Build, stage1 elapsed: " + (start2-start1) );
                System.out.println("Build -- stage 2 alias tabel");
                
                int vaskCount = 0;
                List<AliasBean> aliasList = db.getAliasList();
                for (AliasBean alias : aliasList) {
                        Map<String,Integer> postnrVeje = searchPostnrVejnavnGadeid.get(alias.postnr);
                        
                        if (postnrVeje == null) {
                                //Burde ikke kunne ske - men better safe than sorry
                                continue;
                        }
                        
                        String vasketVej = AddressUtils.vaskVejnavn(alias.vejnavn);
                        String vasketAlias = AddressUtils.vaskVejnavn(alias.aliasVejnavn);
                        
                        Integer gadeident = postnrVeje.get(vasketVej);
                        if (gadeident == null) {
                                //Kender ikke den oprindelige vej
                                continue;
                        }
                        
                        Integer aliasIdent = postnrVeje.get(vasketAlias);
                        
                        if (aliasIdent == null) { //Vi kender ikke denne variant af vejnavnet
                                postnrVeje.put(vasketAlias, gadeident); 
                                vaskCount++;
                        }
                        
                }
                System.out.println("Anvendte " + vaskCount + " aliaser fra databasen");
                
                aliasList.clear();//cleanup inden stage3
                
                
                ////////////////////////////////////////////////////////////////////////////////////////
                long start3 = System.currentTimeMillis();
                System.out.println("Build, stage2 elapsed: " + (start3-start2) );
                System.out.println("Build -- stage 3 udvidet dækning");
                
                DeduplicateHelper<String> ruteHelper = new DeduplicateHelper<String>();
                DeduplicateHelper<String> korelisteHelper = new DeduplicateHelper<String>();
                
                List<ExtendedBean> extDao = db.getExtendedAdresslist();
                for (ExtendedBean eb : extDao) {
                        
                        Address orgAddress = idAddressMap.get(eb.orgId);                        
                        if (orgAddress == null)
                                continue;
                        
                        /*if (orgAddress.daekningsType != DaekningsType.DAEKNING_IKKEDAEKKET) {
                                //kan være at adressen er blevet markeret dækket og - find-nærmeste data ikke er opdateret i mellemtiden
                                continue; 
                        }*/
                        
                        Address targetAddress = idAddressMap.get(eb.targetId);
                        if (targetAddress == null) {
                                continue;
                        }
                        
                        
                        if ( StringUtils.equals(orgAddress.distributor, "LUKKET") ) {
                                continue;
                        }                       
                        
                        
                        if ( StringUtils.equals(targetAddress.distributor, "LUKKET") ) {
                                continue;
                        }
                        
                        orgAddress.extTarget = targetAddress;
                        orgAddress.extAfstand = eb.afstand;

                        boolean covered = false;
                        if (targetAddress.distributor.equals("DAO")) {
                                orgAddress.routingMandag.rute = calculateExtendedDaoRoute(eb, targetAddress.routingMandag);     
                                orgAddress.routingMandag.rute = ruteHelper.getInstance(orgAddress.routingMandag.rute);
                                
                                if (orgAddress.routingMandag.rute != null) {
                                        orgAddress.routingMandag.koreliste = targetAddress.routingMandag.koreliste;
                                        covered = true;
                                }
                        }
                        
                        if (targetAddress.distributor.equals("BK")) {
                                orgAddress.routingMandag.koreliste = calculateExtendedBkKoreliste(eb, targetAddress.routingMandag);
                                orgAddress.routingMandag.koreliste = korelisteHelper.getInstance(orgAddress.routingMandag.koreliste);
                                
                                if (orgAddress.routingMandag.koreliste != null) {
                                        orgAddress.routingMandag.rute = targetAddress.routingMandag.rute;
                                        covered = true;
                                }
                        }
                        
                        if (covered) { //Kopier resten af felterne
                                orgAddress.daekningsType = DaekningsType.DAEKNING_UDVIDET;
                                orgAddress.dbkBane = targetAddress.dbkBane;
                                
                                /* Sådan gør den gamle service */
                                /* 20150520 THN- hvis vi bibeholder de originale kommune+vejkoder kan vi bruge DAVID til join i databasen*/
                                //orgAddress.kommunekode = targetAddress.kommunekode;
                                //orgAddress.vejkode = targetAddress.vejkode;
                                
                                
                                orgAddress.distributor = targetAddress.distributor;
                        }
                }
                
                // cleanup inden stage 4
                idAddressMap = null;
                ruteHelper = null;
                korelisteHelper = null;
                
                //////////////////////////////////////////////////////////////////////////////////////
                long start4 = System.currentTimeMillis();
                System.out.println("Build, stage3 elapsed: " + (start4-start3) );
                System.out.println("Build -- stage 4 - 100pct");
                
                Map<Short,HundredePctBean> hundredePct = db.get100PctList();
                for (Address addr : alleAdresser) {
                        if (addr.daekningsType != DaekningsType.DAEKNING_IKKEDAEKKET) {                         
                                continue;
                        }
                        
                        if (addr.distributor != null && addr.distributor.equals("LUKKET")) {
                                continue;
                        }
                        
                        
                        HundredePctBean bean = hundredePct.get(addr.postnr);
                        if (bean == null) {
                                continue;
                        }
                        
                        addr.daekningsType = DaekningsType.DAEKNING_100PCT;
                        addr.routingMandag.rute = bean.rute;
                        addr.routingMandag.koreliste = bean.koreliste;
                        addr.dbkBane = bean.dbkBane;
                        addr.distributor = bean.distributor;
                }
                
                ////////////////////////////////////////////////////////////////////////////////////
                long stop = System.currentTimeMillis();
                System.out.println("Build, stage4 elapsed: " + (stop-start4) );
                System.out.println("Build -- Gathering statistics");
                                
                for (Address addr : alleAdresser) {
                        switch (addr.daekningsType) {
                        case DAEKNING_DIREKTE:
                                stats.direkteCount++;
                                break;
                        case DAEKNING_UDVIDET:
                                stats.extendedCount++;
                                break;
                        case DAEKNING_100PCT:
                                hundredePctAdresser.add(addr);
                                stats.hundredePctCount++;
                                break;
                        default:
                                ikkeDaekkedeAdresser.add(addr);
                                stats.ikkeDaekketCount++;
                        }
                }               
                stats.totalCount = alleAdresser.size();
                
                ikkeDaekkedeAdresser.trimToSize();
                hundredePctAdresser.trimToSize();
                Collections.sort( ikkeDaekkedeAdresser ); //Bruger Comparable interfacet
                Collections.sort( hundredePctAdresser );

                
                stats.elapsed = stop-start1;            
                stats.buildTime = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format( new Date() );
                
                System.out.println("Build: totalCount: " + stats.totalCount);
                System.out.println("Build: direkteCount: " + stats.direkteCount);
                System.out.println("Build: extendedCount: " + stats.extendedCount);
                System.out.println("Build: hundredePctCount: " + stats.hundredePctCount);
                System.out.println("Build: ikkeDaekketCount: " + stats.ikkeDaekketCount);
                
                System.out.println("Build: Total Elapsed: " + (stop-start1) );
                System.out.println("Build Completed");
                
        }
        
        public DataStatisticsBean getStatistics() {
                return stats;
        }
        
        public DatabaseLayer getDatabaseLayer() {
                return db;
        }
        
        public void clear() {
                searchPostnrVejnavnGadeid.clear();
                searchGadeidentAdresser.clear();
                helperCache.clear();
        }
        
        
        private String calculateExtendedDaoRoute(ExtendedBean eb, RoutingInfo targetRoute) {
                if (targetRoute.rute == null) { //hvis targetAdress.rute er null så er adressen ikke dækket alligevel
                        return null;
                }

                // ///////////////////////////////////////////////////////////////////
                switch( eb.transport) {
                case "cykel":
                        if (eb.afstand < 0.151) {
                                return "." + targetRoute.rute;
                        } else if (eb.afstand < 0.501) {
                                return ".." + targetRoute.rute;
                        } else if (eb.afstand < 0.701) {
                                return "..." + targetRoute.rute;
                        } else if (eb.afstand < 1.001) {
                                return "...." + targetRoute.rute;
                        }
                        break;                  
                case "scooter":
                        if (eb.afstand < 0.151) {
                                return "." + targetRoute.rute;
                        } else if (eb.afstand < 0.801) {
                                return ".." + targetRoute.rute;
                        } else if (eb.afstand < 1.201) {
                                return "..." + targetRoute.rute;
                        } else if (eb.afstand < 2.101) {
                                return "...." + targetRoute.rute;
                        }
                        break;                          
                case "bil":
                        if (eb.afstand < 0.151) {
                                return "." + targetRoute.rute;
                        } else if (eb.afstand < 1.001) {
                                return ".." + targetRoute.rute;
                        } else if (eb.afstand < 1.601) {
                                return "..." + targetRoute.rute;
                        } else if (eb.afstand < 2.601) {
                                return "...." + targetRoute.rute;
                        }
                        break;
                default:
                        System.out.println("Ukendt transport type: " + eb );
                }               
                return null;
        }
        
        public List<Address> getNonCoveredAddresses() {
                return ikkeDaekkedeAdresser;
        }
        
        public List<Address> get100PctAddresses() {
                return hundredePctAdresser;
        }
        
        ///////////////////////////////////////////////////////////
        private String calculateExtendedBkKoreliste(ExtendedBean eb, RoutingInfo targetRoute) {
                if (targetRoute.rute == null) { //hvis targetAdress.rute er null så er adressen ikke dækket alligevel
                        return null;
                }
                
                String inject;
                if (eb.afstand <= 0.500) {
                        inject = ".";
                } else {
                        inject = "..";
                }
                return AddressUtils.injectIntoBk(targetRoute.koreliste, inject);
        }
        
        
        public Set<Short> getPostnumre() {
                return new TreeSet<Short>( searchPostnrVejnavnGadeid.keySet() );
        }
        
        public Set<Entry<String,Integer>> getVejnavne(short postnr) {
                Map<String,Integer> map = searchPostnrVejnavnGadeid.get(postnr);
                
                TreeMap<String,Integer> newMap = new TreeMap<String,Integer>( map );//Lav et nyt TreeMap for at sikre sortering
                
                return newMap.entrySet();
        }
        
        public Set<String> getHusnumre(int gadeid) {
                                
                Map<Short, List<Address>> gade = searchGadeidentAdresser.get(gadeid);
                
                Set<String> set = new TreeSet<String>( new NaturalOrderComparator<String>() );
                for(List<Address> litraList : gade.values()) {
                        for (Address a: litraList) {
                                set.add( a.husnr + a.husnrbogstav );                            
                        }
                }
                
                return set;
        }
        
        public Address getAdresse(int gadeid, String husnrStr) {
                short husnr = Short.parseShort( husnrStr.replaceAll("[^\\d]","") );
                String litra =  husnrStr.replaceAll("\\d", "");         
                
                Map<Short,List<Address>> gade = searchGadeidentAdresser.get(gadeid);
                List<Address> litraList = gade.get(husnr);
                
                for(Address addr : litraList) {
                        if (addr.husnrbogstav.equals(litra)) {
                                return addr;
                        }
                }
                
                return null;
                
        }
                
}