Reading from JSON Array data now works differently

Author: JohannesJander

src/main/java/io/frictionlessdata/tableschema/Table.java

@@ -461,7 +461,7 @@ private void writeCsv(Writer out, CSVFormat format, String[] sortedHeaders) {
             String[] headers = getHeaders();
             Map<Integer, Integer> mapping
                     = TableSchemaUtil.createSchemaHeaderMapping(headers, sortedHeaders, dataSource.hasReliableHeaders());
-            if (null != schema) {
+            if ((null != schema)) {
                 writeCSVData(mapping, schema, csvPrinter);
             } else {
                 writeCSVData(mapping, csvPrinter);

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

@@ -43,7 +43,17 @@ public JsonArrayTableDataSource (String json){
 
     @Override
     public boolean hasReliableHeaders() {
-        return false;
+		if (dataSource == null) {
+			return false;
+		}
+		Iterator iter = dataSource.elements();
+		if (!iter.hasNext()) {
+			return false;
+		}
+		JsonNode first = (JsonNode) iter.next();
+		if (first instanceof ObjectNode) {
+			return false;
+		} else return first instanceof ArrayNode;
     }
 
 

src/main/java/io/frictionlessdata/tableschema/util/TableSchemaUtil.java

@@ -25,7 +25,7 @@ public static Map<Integer, Integer> createSchemaHeaderMapping(
             // - if no header row in CSV data (throw)
             // - with JSON Arrays of JSON objects as they will not have keys for null values (accept, but don't map)
             if (!mapping.containsKey(i)) {
-                if (reliableHeaders) {
+                if (reliableHeaders ) {
                     throw new TableValidationException("Field '" + sortedHeaders[i] + "' not found in table headers or table has no headers.");
                 } else {
                     mapping.put(i, null);

src/test/java/io/frictionlessdata/tableschema/fk/ForeignKeyTest.java

@@ -4,6 +4,7 @@
 import io.frictionlessdata.tableschema.Table;
 import io.frictionlessdata.tableschema.TestHelper;
 import io.frictionlessdata.tableschema.exception.ForeignKeyException;
+import io.frictionlessdata.tableschema.exception.ValidationException;
 import io.frictionlessdata.tableschema.schema.Schema;
 import io.frictionlessdata.tableschema.util.JsonUtil;
 import org.apache.commons.csv.CSVFormat;
@@ -57,6 +58,32 @@ public void testInvalidFkReference() throws Exception {
                 fke.getMessage());
     }
 
+    @Test
+    @DisplayName("data validation. Check Schema with ForeignKey against not matching data -> must throw")
+    public void testInvalidFkReferenceFromSchema() throws Exception {
+        File testDataDir = TestHelper.getTestDataDirectory();
+        File source = TestHelper.getResourceFile("/fixtures/schema/population_schema_for_fk_check.json");
+
+        Schema schema = Schema.fromJson(source, true);
+        // get path of test CSV file
+        File file = new File("data/population_for_fk_check_invalid.csv");
+        Table table = Table.fromSource(
+                file,
+                testDataDir,
+                schema,
+                CSVFormat.DEFAULT.builder().setHeader().get());
+        ValidationException valE = assertThrows(ValidationException.class, ()
+                -> schema.validate(table));
+        Assertions.assertFalse(valE.getWrappedExceptions().isEmpty());
+        Exception fke = valE.getWrappedExceptions().get(0);
+        Assertions.assertInstanceOf(ForeignKeyException.class, fke);
+        Assertions.assertEquals("Foreign key [check_year-> year] violation : expected: 2018 found: 2017",
+                fke.getMessage());
+        Assertions.assertEquals("Validation failed with ForeignKeyException: Foreign key [check_year-> year] violation : expected: 2018 found: 2017",
+                valE.getMessage());
+
+    }
+
     @Test
     @DisplayName("formal validation, both fk fields and reference fields are strings")
     public void testValidStringFields() throws ForeignKeyException {