Tweaked the library to support inheritance

- Updated FixedLength.java
- Updated ParserTest.java
- Updated FormatterTest.java
- Created InheritedEmployee.java
- Created AbstractPerson.java

src/main/java/name/velikodniy/vitaliy/fixedlength/FixedLength.java

@@ -53,7 +53,7 @@ private FixedFormatLine<T> classToLineDesc(final Class<? extends T> clazz) {
         if (annotation != null) {
             fixedFormatLine.startsWith = annotation.startsWith();
         }
-        for (Field field : clazz.getDeclaredFields()) {
+        for (Field field : getAllFields(clazz)) {
             FixedField fieldAnnotation = field.getDeclaredAnnotation(FixedField.class);
             if (fieldAnnotation == null) {
                 continue;
@@ -71,6 +71,17 @@ private FixedFormatLine<T> classToLineDesc(final Class<? extends T> clazz) {
         return fixedFormatLine;
     }
 
+    List<Field> getAllFields(final Class<?> clazz) {
+        if (clazz == null) {
+            return Collections.emptyList();
+        }
+
+        List<Field> result = new ArrayList<>(getAllFields(clazz.getSuperclass()));
+        List<Field> filteredFields = Arrays.stream(clazz.getDeclaredFields()).collect(Collectors.toList());
+        result.addAll(filteredFields);
+        return result;
+    }
+
     public FixedLength<T> registerLineType(final Class<? extends T> lineClass) {
         lineTypes.add(classToLineDesc(lineClass));
         return this;
@@ -306,7 +317,8 @@ public String format(List<T> lines) {
 
         for (T line : lines) {
 
-            Arrays.stream(line.getClass().getDeclaredFields())
+            getAllFields(line.getClass())
+                    .stream()
                     .filter(
                             f ->
                                     f.getAnnotation(FixedField.class) != null

src/test/java/AbstractPerson.java

@@ -0,0 +1,10 @@
+import name.velikodniy.vitaliy.fixedlength.Align;
+import name.velikodniy.vitaliy.fixedlength.annotation.FixedField;
+
+public abstract class AbstractPerson {
+    @FixedField(offset = 1, length = 10, align = Align.LEFT)
+    public String firstName;
+
+    @FixedField(offset = 11, length = 10, align = Align.LEFT)
+    String lastName;
+}

src/test/java/FormatterTest.java

@@ -27,4 +27,19 @@ void simpleFormat() {
 
     }
 
+
+    @Test
+    @DisplayName("Simple string format class hierarchy")
+    void simpleFormatInherited() {
+
+        FixedLength<Row> impl = new FixedLength<Row>()
+                .registerLineType(InheritedEmployee.class);
+
+        List<Row> parse = impl
+                .parse(new ByteArrayInputStream(singleTypeExample.getBytes()));
+
+        assertEquals(singleTypeExample, impl.format(parse));
+
+    }
+
 }

src/test/java/InheritedEmployee.java

@@ -0,0 +1,18 @@
+import name.velikodniy.vitaliy.fixedlength.Align;
+import name.velikodniy.vitaliy.fixedlength.annotation.FixedField;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+
+public class InheritedEmployee extends AbstractPerson implements Row {
+
+    @FixedField(offset = 21, length = 10, align = Align.LEFT)
+    protected String title;
+
+    @FixedField(offset = 31, length = 6, padding = '0')
+    private BigDecimal salary;
+
+    @FixedField(offset = 37, length = 8, format = "MMddyyyy")
+    public LocalDate hireDate;
+
+}

src/test/java/ParserTest.java

@@ -45,6 +45,21 @@ class ParserTest {
             "CatSnowball  20200103@" +
             "EmplJoe3      Smith     Developer ";
 
+    @Test
+    @DisplayName("Parse as input stream with default charset and one line type")
+    void testParseInheritedOneLineType() throws FixedLengthException {
+        List<Row> parse = new FixedLength<Row>()
+                .registerLineType(InheritedEmployee.class)
+                .parse(new ByteArrayInputStream(singleTypeExample.getBytes()));
+
+        assertEquals(2, parse.size());
+        parse.forEach( e ->{
+            assertNotNull(((InheritedEmployee)e).firstName);
+            assertNotNull(((InheritedEmployee)e).lastName);
+        });
+    }
+
+
     @Test
     @DisplayName("Parse as input stream with default charset and one line type")
     void testParseOneLineType() throws FixedLengthException {