Improvements in encoding and validationexceptions

Author: JohannesJander

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

@@ -7,6 +7,7 @@
 
 import java.net.URI;
 import java.util.*;
+import java.util.stream.Collectors;
 
 public class BooleanField extends Field<Boolean> {
     @JsonIgnore
@@ -59,7 +60,9 @@ public Boolean parseValue(String value, String format, Map<String, Object> optio
             return false;
 
         }else{
-            throw new TypeInferringException("Value "+value+" not in 'trueValues' or 'falseValues'");
+            String trueStr = (null == trueValues) ? "" : " ("+String.join(", ", trueValues)+") ";
+            String falseStr = (null == falseValues) ? "" : " ("+String.join(", ", falseValues)+") ";
+            throw new TypeInferringException("Value '"+value+"' not in 'trueValues' "+ trueStr +" or 'falseValues' "+ falseStr + "");
         }
     }
 

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

@@ -627,10 +627,12 @@ T castValue(String value, boolean enforceConstraints, Map<String, Object> option
 
                 return castValue;
 
-            }catch(ConstraintsException ce){
+            } catch(ConstraintsException ce){
                 throw ce;
 
-            }catch(Exception e){
+            } catch(TypeInferringException e){
+                throw new InvalidCastException(e.getMessage());
+            } catch(Exception e){
                 throw new InvalidCastException(e);
             }
         }

src/main/java/io/frictionlessdata/tableschema/tabledatasource/TableDataSource.java

@@ -8,6 +8,8 @@
 import org.apache.commons.csv.CSVFormat;
 
 import java.io.*;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.HashMap;
@@ -218,6 +220,21 @@ static Path toSecure(Path testPath, Path referencePath) throws IOException {
         return resolvedPath;
     }
 
+    /**
+     * Get the standard {@link Charset} (encoding) to use if none is specified. According to the Datapackage
+     * specs, this should not be the platform default, but UTF-8: "specify the character encoding of the
+     * resource’s data file. The values should be one of the “Preferred MIME Names” for a character encoding
+     * registered with IANA . If no value for this key is specified then the default is UTF-8."
+     * From: https://specs.frictionlessdata.io/data-resource/#metadata-properties
+     *
+     * We assume the same should apply for Tables.
+     *
+     * @return the default Charset
+     */
+    public static Charset getDefaultEncoding() {
+        return StandardCharsets.UTF_8;
+    }
+
     /**
      * Data format, currently either CSV or JSON. Formats like Excel are not supported
      */