Picked some changes from gbif branch

Author: JohannesJander

src/main/java/io/frictionlessdata/tableschema/field/Field.java

@@ -15,6 +15,7 @@
 import java.util.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 /**
  * Definition of a field in a data table. Doesn't hold values
@@ -651,7 +652,8 @@ T castValue(String value, boolean enforceConstraints, Map<String, Object> option
                 if(enforceConstraints && this.constraints != null){
                     Map<String, Object> violatedConstraints = checkConstraintViolations(castValue);
                     if(!violatedConstraints.isEmpty()){
-                        throw new ConstraintsException("Violated "+ violatedConstraints.size()+" constraints");
+                        String violatedConstraintNames = String.join(", ", violatedConstraints.keySet());
+                        throw new ConstraintsException("Field '" + this.name + "' value '" + value + "' violates constraint(s) [" + violatedConstraintNames+"]");
                     }
                 }
 
@@ -660,7 +662,7 @@ T castValue(String value, boolean enforceConstraints, Map<String, Object> option
             } catch(ConstraintsException ce){
                 throw ce;
             } catch (TypeInferringException e) {
-                throw new InvalidCastException("Field [" + this.name + "] provided value [" + value + "] is not of [" + type + "] type.");
+                throw new InvalidCastException("Field '" + this.name + "' provided value '" + value + "' is not of '" + type + "' type.");
             } catch(Exception e){
                 throw new InvalidCastException(e);
             }

src/test/java/io/frictionlessdata/tableschema/field/FieldConstraintsTest.java

@@ -5,6 +5,7 @@
 import io.frictionlessdata.tableschema.exception.ConstraintsException;
 import io.frictionlessdata.tableschema.util.JsonUtil;
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 import java.math.BigInteger;
@@ -95,7 +96,8 @@ public void testMinAndMaxLengthString() throws Exception{
         violatedConstraints = field.checkConstraintViolations(valueLength49);
         Assertions.assertTrue(violatedConstraints.containsKey(Field.CONSTRAINT_KEY_MAX_LENGTH));
 
-        assertThrows(ConstraintsException.class, () -> {field.castValue("This string length is greater than 45 characters.");});
+        ConstraintsException ex = assertThrows(ConstraintsException.class, () -> {field.castValue("This string length is greater than 45 characters.");});
+        Assertions.assertEquals("Field 'test' value 'This string length is greater than 45 characters.' violates constraint(s) [maxLength]", ex.getMessage());
     }
 
     @Test
@@ -783,6 +785,26 @@ public void testEnumYearMonth(){
     }
 
 
+    @Test
+    @DisplayName("Test our validation message shows both pattern and maxLength constraints violated")
+    public void testPatternAndMaxlength(){
+        Map<String, Object> violatedConstraints = null;
+
+        Map<String, Object> constraints = new HashMap<>();
+        constraints.put(Field.CONSTRAINT_KEY_PATTERN, "testing[0-9]+");
+        constraints.put(Field.CONSTRAINT_KEY_MAX_LENGTH, 45);
+
+        StringField field = new StringField("test", null, null, null, null, constraints, null, null);
+
+        String valueLength49 = field.castValue("This string length is greater than 45 characters.", false, null);
+        violatedConstraints = field.checkConstraintViolations(valueLength49);
+        Assertions.assertTrue(violatedConstraints.containsKey(Field.CONSTRAINT_KEY_MAX_LENGTH));
+        Assertions.assertTrue(violatedConstraints.containsKey(Field.CONSTRAINT_KEY_PATTERN));
+
+        ConstraintsException ex = assertThrows(ConstraintsException.class, () -> {field.castValue("This string length is greater than 45 characters.");});
+        Assertions.assertEquals("Field 'test' value 'This string length is greater than 45 characters.' violates constraint(s) [pattern, maxLength]", ex.getMessage());
+    }
+
     private JsonNode createJsonNode(Object obj) {
     	return JsonUtil.getInstance().createNode(obj);
     }