Using Google Maps API Place Autocomplete with Salesforce Apex

GoogleMapsAutoCompleteAPI.apex

public class GoogleMapsAutoCompleteAPI {

    // Google Maps API Place Autocomplete
    // Documentation: https://developers.google.com/places/web-service/autocomplete

    public PlaceAutocompleteResponse getAutoComplete(String input, String types, String components) {
        String url = 'https://maps.googleapis.com/maps/api/place/autocomplete/json?input='
            + EncodingUtil.urlEncode(input, 'UTF-8')
            + '&components=' + components // country:uk'
            + '&types=' + types
            + '&key=' + getGoogleMapsAPIKey();
        
        return PlaceAutocompleteResponse.parse(makeAPICall(url));
    }
     
    private string makeAPICall(string url) {
        
        Http http = new Http();
        HttpRequest httpRequest = new HttpRequest();
        HttpResponse httpResponse = new HttpResponse();
        httpRequest.setMethod('GET');
        httpRequest.setEndpoint(url);
        httpRequest.setTimeout(120000);
        httpResponse = http.send(httpRequest); 

        return httpResponse.getBody();
    }
    
    private string getAPIKey() {
        return ''; // add api key or get from custom settings
    }
}

public class PlaceAutocompleteResponse {

    public class Matched_substrings {
        public Integer length;
        public Integer offset;
    }

    public String status;
    public List<Predictions> predictions;

    public class Predictions {
        public String description;
        public String id;
        public List<Matched_substrings> matched_substrings;
        public String place_id;
        public String reference;
        public List<Terms> terms;
        public List<String> types;
    }

    public class Terms {
        public Integer offset;
        public String value;
    }

    public static PlaceAutocompleteResponse parse(String json) {
         return (PlaceAutocompleteResponse) System.JSON.deserialize(json, PlaceAutocompleteResponse.class);
    }
}