#21 improved information about non-defined Bin attribute

Author: raydac

jbbp/src/main/java/com/igormaznitsa/jbbp/utils/JBBPDslBuilder.java

@@ -1521,6 +1521,7 @@ protected BinFieldContainer collectAnnotatedFields(final Class<?> annotatedClass
       if ((f.getModifiers() & (Modifier.NATIVE | Modifier.STATIC | Modifier.FINAL | Modifier.PRIVATE | Modifier.TRANSIENT)) == 0) {
         final Bin binAnno = f.getAnnotation(Bin.class);
         if (binAnno != null || defautBin != null) {
+          validateAnnotatedField(defautBin, binAnno, f);
           final Class<?> type = f.getType().isArray() ? f.getType().getComponentType() : f.getType();
           if (type.isPrimitive() || type == String.class) {
             final Bin foundBin = binAnno == null ? defautBin : binAnno;
@@ -1548,6 +1549,15 @@ protected BinFieldContainer collectAnnotatedFields(final Class<?> annotatedClass
     return result;
   }
 
+  protected void validateAnnotatedField(final Bin defaultBin, final Bin fieldBin, final Field field) {
+    final Bin thebin = fieldBin == null ? defaultBin : fieldBin;
+    final boolean emptyExtra = thebin.extra().trim().length() == 0;
+
+    if ((thebin.type() == BinType.UNDEFINED && field.getType().isArray() || thebin.type().name().endsWith("_ARRAY")) && emptyExtra) {
+      throw new IllegalArgumentException(field.toString() + ": missing array length expression in Bin#extra");
+    }
+  }
+
   /**
    * Convert an annotated class into its JBBP DSL representation.
    * <b>NB!</b> the method creates structure bases on class name, so that it can't be used for auto-mapping

jbbp/src/test/java/com/igormaznitsa/jbbp/utils/JBBPDslBuilderTest.java

@@ -498,6 +498,38 @@ class Internal {
     assertEquals("Test{int a;<int b;int c;d[a+b]{short a;short[8] b;}}", Begin().AnnotatedClass(Test.class).End());
   }
 
+  @Test
+  public void testReportedIssue_21_IAEforEmptyExtraAttributeForArrayField() {
+    class BreakJBBPDslBuilderChild {
+      @Bin(outOrder = 1, comment = "Reserved", type = BinType.BYTE)
+      public byte reserved;
+    }
+
+    class BreakJBBPDslBuilderParent {
+      @Bin(outOrder = 1)
+      public BreakJBBPDslBuilderChild[] breakJBBPDslBuilderChildArray;
+    }
+
+    class BreakJBBPDslBuilderArrayField {
+      @Bin(outOrder = 1, type = BinType.BYTE_ARRAY)
+      public byte[] bytes;
+    }
+
+    try {
+      Begin().AnnotatedClass(BreakJBBPDslBuilderParent.class).End();
+      fail();
+    } catch (IllegalArgumentException ex) {
+      assertTrue(ex.getMessage().contains("Bin#extra"));
+    }
+
+    try {
+      Begin().AnnotatedClass(BreakJBBPDslBuilderArrayField.class).End();
+      fail();
+    } catch (IllegalArgumentException ex) {
+      assertTrue(ex.getMessage().contains("Bin#extra"));
+    }
+  }
+
   @Test
   public void testReportedIssue_20_NPEforOutBitNumber() throws Exception {
     class BreakJBBPDslBuilder {