MTC Field length validation

src/main/java/com/conveyal/gtfs/error/NewGTFSErrorType.java

@@ -11,6 +11,7 @@ public enum NewGTFSErrorType {
     URL_FORMAT(Priority.MEDIUM, "URL format should be <scheme>://<authority><path>?<query>#<fragment>"),
     LANGUAGE_FORMAT(Priority.LOW, "Language should be specified with a valid BCP47 tag."),
     ILLEGAL_FIELD_VALUE(Priority.MEDIUM, "Fields may not contain tabs, carriage returns or new lines."),
+    // The error type below is an MTC-specific requirement.
     FIELD_VALUE_TOO_LONG(Priority.MEDIUM, "Field value has too many characters."),
     INTEGER_FORMAT(Priority.MEDIUM, "Incorrect integer format."),
     FARE_TRANSFER_MISMATCH(Priority.MEDIUM, "A fare that does not permit transfers has a non-zero transfer duration."),

src/main/java/com/conveyal/gtfs/validator/MTCValidator.java

@@ -4,12 +4,18 @@
 import com.conveyal.gtfs.loader.Feed;
 import com.conveyal.gtfs.model.*;
 
+import java.net.URL;
+
 import static com.conveyal.gtfs.error.NewGTFSErrorType.FIELD_VALUE_TOO_LONG;
 
 /**
- * MTCValidator checks in a GTFS feed that the length of certain field values
- * do not exceed the 511 MTC guidelines. (TODO: add guidelines URL.)
- * To refer to specific limits, search the guidelines for the word 'character'.
+ * MTCValidator runs a set of custom validation checks for GTFS feeds managed by MTC in Data Tools.
+ * The checks consist of validating field lengths at this time per the 511 MTC guidelines at
+ * https://github.com/ibi-group/datatools-ui/files/4438625/511.Transit_Data.Guidelines_V2.0_3-27-2020.pdf.
+ * For specific field lengths, search the guidelines for the word 'character'.
+ *
+ * Note that other validations, e.g. on GTFS+ files, are discussed in
+ * https://github.com/ibi-group/datatools-ui/issues/544.
  */
 public class MTCValidator extends FeedValidator {
 
@@ -20,37 +26,38 @@ public MTCValidator(Feed feed, SQLErrorStorage errorStorage) {
     @Override
     public void validate() {
         for (Agency agency : feed.agencies) {
-            fieldLengthShouldNotExceed(agency, agency.agency_id, 50);
-            fieldLengthShouldNotExceed(agency, agency.agency_name, 50);
-            fieldLengthShouldNotExceed(agency, agency.agency_url, 500);
+            validateFieldLength(agency, agency.agency_id, 50);
+            validateFieldLength(agency, agency.agency_name, 50);
+            validateFieldLength(agency, agency.agency_url, 500);
         }
 
         for (Stop stop : feed.stops) {
-            fieldLengthShouldNotExceed(stop, stop.stop_name, 100);
+            validateFieldLength(stop, stop.stop_name, 100);
         }
 
         for (Trip trip : feed.trips) {
-            fieldLengthShouldNotExceed(trip, trip.trip_headsign, 120);
-            fieldLengthShouldNotExceed(trip, trip.trip_short_name, 50);
+            validateFieldLength(trip, trip.trip_headsign, 120);
+            validateFieldLength(trip, trip.trip_short_name, 50);
         }
-
-        // TODO: Handle calendar_attributes.txt?
     }
 
     /**
-     * Checks that the length of a string (or Object.toString()) does not exceed a length.
+     * Checks that the length of a string does not exceed a certain length.
      * Reports an error if the length is exceeded.
      * @param entity The containing GTFS entity (for error reporting purposes).
-     * @param objValue The value to check.
+     * @param value The String value to check.
      * @param maxLength The length to check, should be positive or zero.
-     * @return true if the length of objValue.toString() is maxLength or less or if objValue is null; false otherwise.
+     * @return true if value.length() is maxLength or less, or if value is null; false otherwise.
      */
-    public boolean fieldLengthShouldNotExceed(Entity entity, Object objValue, int maxLength) {
-        String value = objValue != null ? objValue.toString() : "";
-        if (value.length() > maxLength) {
+    public boolean validateFieldLength(Entity entity, String value, int maxLength) {
+        if (value != null && value.length() > maxLength) {
             if (errorStorage != null) registerError(entity, FIELD_VALUE_TOO_LONG, "[over " + maxLength + " characters] " + value);
             return false;
         }
         return true;
     }
+
+    public boolean validateFieldLength(Entity entity, URL url, int maxLength) {
+        return validateFieldLength(entity, url != null ? url.toString() : "", maxLength);
+    }
 }

src/test/java/com/conveyal/gtfs/validator/MTCValidatorTest.java

@@ -12,8 +12,8 @@ public class MTCValidatorTest {
     @Test
     public void fieldlLengthShouldNotExceed() {
         MTCValidator validator = new MTCValidator(null, null);
-        assertThat(validator.fieldLengthShouldNotExceed(null, "abcdefghijklmnopqrstwxyz1234567890", 20), is(false));
-        assertThat(validator.fieldLengthShouldNotExceed(null, "abcdef", 20), is(true));
+        assertThat(validator.validateFieldLength(null, "abcdefghijklmnopqrstwxyz1234567890", 20), is(false));
+        assertThat(validator.validateFieldLength(null, "abcdef", 20), is(true));
     }
 
     @Test
@@ -22,7 +22,7 @@ public void fieldlLengthShouldNotExceed_usingObject() throws MalformedURLExcepti
 
         // You can also pass objects, in that case it will use toString().
         URL url = new URL("http://www.gtfs.org");
-        assertThat(validator.fieldLengthShouldNotExceed(null, url, 10), is(false));
-        assertThat(validator.fieldLengthShouldNotExceed(null, url, 30), is(true));
+        assertThat(validator.validateFieldLength(null, url, 10), is(false));
+        assertThat(validator.validateFieldLength(null, url, 30), is(true));
     }
 }