Dest_Location

// APEX CODE IS HERE!!!

public class dest_geolucationtry
{
    
         @future (callout=true)  // future method needed to run callouts from Triggers
      static public void getLocation(id accountId){
        // gather account info
        Account b = [SELECT ShippingCity,ShippingCountry,ShippingPostalCode,ShippingState,ShippingStreet FROM Account WHERE id =: accountId];

        // create an address string
        String address = '';
        if (b.ShippingStreet != null)
            address += b.ShippingStreet +', ';
        if (b.ShippingCity != null)
            address += b.ShippingCity +', ';
        if (b.ShippingState != null)
            address += b.ShippingState +' ';
        if (b.ShippingPostalCode != null)
            address += b.ShippingPostalCode +', ';
        if (b.ShippingCountry != null)
            address += b.ShippingCountry;

        address = EncodingUtil.urlEncode(address, 'UTF-8');

        // build callout
        Http h = new Http();
        HttpRequest req = new HttpRequest();
        req.setEndpoint('http://maps.googleapis.com/maps/api/geocode/json?address='+address+'&sensor=false');
        req.setMethod('GET');
        req.setTimeout(60000);

        try{
            // callout
            HttpResponse res = h.send(req);

            // parse coordinates from response
            JSONParser parser = JSON.createParser(res.getBody());
            double lati = null;
            double longi = null;
            while (parser.nextToken() != null) {
                if ((parser.getCurrentToken() == JSONToken.FIELD_NAME) &&
                    (parser.getText() == 'location')){
                       parser.nextToken(); // object start
                       while (parser.nextToken() != JSONToken.END_OBJECT){
                           String txt = parser.getText();
                           parser.nextToken();
                           if (txt == 'lat')
                               lati = parser.getDoubleValue();
                           else if (txt == 'lng')
                               longi = parser.getDoubleValue();
                       }

                }
            }

            // update coordinates if we get back
            if (lati != null){
                b.Dest_Location__Latitude__s = lati;
                b.Dest_Location__Longitude__s = longi;
                update b;
                system.debug(b);
            }

        } catch (Exception e) {
        }
    }



}




// THIS IS TRIGGER CODE :

trigger location_set on Account (after insert, after update) 
{
    
    for (Account b : trigger.new)
        if (b.Dest_Location__Latitude__s == null)
            dest_geolucationtry.getLocation(b.id);


}