Hey guys, so I have a trigger than runs whenever an address is updated or saved, to do reverse geocode and write the latitude and logitude to a field. The problem is, when a lot of records are updated at once, I run into the future call limit governer.....

See the code below: Any help is much appreciated.
 

/*// Trigger runs getLocation() on Accounts with no Geolocation

trigger SetGeolocation on Account (after insert, after update) {
    for (Account a : trigger.new)
    if (a.Location__Latitude__s == null)
          LocationCallouts.getLocation(a.id);
}*/

// Trigger runs getLocation() on Accounts with no Geolocation

trigger SetGeolocation on Account (after insert, after update) {
    for (Account a : trigger.new){
        if(system.isFuture() == FALSE){
          LocationCallouts.getLocation(a.id);
        }
    }
}

that's the trigger, which then runs this apex class:
 

public class LocationCallouts {

     @future (callout=true)  // future method needed to run callouts from Triggers
      static public void getLocation(id accountId){
        // gather account info
        Account a = [SELECT BillingCity,BillingCountry,BillingPostalCode,BillingState,BillingStreet FROM Account WHERE id =: accountId];

        // create an address string
        String address = '';
        if (a.BillingStreet != null)
            address += a.BillingStreet +', ';
        if (a.BillingCity != null)
            address += a.BillingCity +', ';
        if (a.BillingState != null)
            address += a.BillingState +' ';
        if (a.BillingPostalCode != null)
            address += a.BillingPostalCode +', ';
        if (a.BillingCountry != null)
            address += a.BillingCountry;

        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 lat = null;
            double lon = 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')
                               lat = parser.getDoubleValue();
                           else if (txt == 'lng')
                               lon = parser.getDoubleValue();
                       }

                }
            }

            // update coordinates if we get back
            if (lat != null){
                a.Location__Latitude__s = lat;
                a.Location__Longitude__s = lon;
                update a;
            }

        } catch (Exception e) {
        }
    }
}

This works very well, until you try to update a lot of records at once....when you do you run into the @future calls limit.


I had read that using a batch apex class can solve this, any advice on how to do that is appreciated.

I had posted a previous thread where another developer suggested I use a list to get around this, and it seemed to work, but after testing it, it broke the writing of geocode to the location field. See this thread: https://developer.salesforce.com/forums/ForumsMain?id=906F0000000B2h8IAC