Updated docs

src/main/java/net/fortuna/ical4j/validate/ValidationRule.java

@@ -4,6 +4,13 @@
 import java.util.Arrays;
 import java.util.List;
 
+/**
+ * Defines a rule for validating iCalendar content. A rule consists of a validation type (e.g. presence/absence of
+ * specific content), and one or more identifiers (names) of iCalendar content.
+ *
+ * For example, a rule might define a test for one or less DTEND properties using the "OneOrLess" validation type
+ * and "DTEND" identifier.
+ */
 public class ValidationRule implements Serializable {
 
     public enum ValidationType { None,  One, OneOrLess, OneOrMore }

src/main/java/net/fortuna/ical4j/validate/Validator.java

@@ -38,8 +38,10 @@
 import java.util.function.Predicate;
 
 /**
- * @author fortuna
+ * Implementors apply validation rules to iCalendar content to determine a level of compliance with the published
+ * specifications.
  *
+ * @author fortuna
  */
 public interface Validator<T> extends Serializable {
 
@@ -56,8 +58,9 @@ static <T> void assertFalse(Predicate<T> predicate, String message, boolean warn
     }
 
     /**
-     * Validates the associated model against an applicable standard.
-     * @throws ValidationException where the model does not confirm to the applicable standard
+     * Validates the target content by applying validation rules. When content fails validation the validator
+     * may throw an exception depending on the implementation.
+     * @throws ValidationException indicates validation failure (implementation-specific)
      */
     void validate(T target) throws ValidationException;
 }