added test and improved comments

Author: raydac

jbbp/src/main/java/com/igormaznitsa/jbbp/mapper/Bin.java

@@ -85,8 +85,7 @@
   boolean custom() default false;
 
   /**
-   * The Filed contains some extra text info which can be used by a custom field
-   * processor, the engine doesn't use the field.
+   * The Field is used by custom field processor and as expression to calculate array length.
    *
    * @return the extra field as String
    * @see JBBPMapperCustomFieldProcessor

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

@@ -1550,21 +1550,26 @@ protected BinFieldContainer collectAnnotatedFields(final Class<?> annotatedClass
 
   /**
    * 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
+   * if you want use auto-mapping, use {@link JBBPDslBuilder#AnnotatedClassFields(Class)}
    *
    * @param annotatedClass class to be converted into JBBP script, must not be null
    * @return the builder instance, must not be null
-   * @see com.igormaznitsa.jbbp.mapper.Bin
+   * @see JBBPDslBuilder#AnnotatedClassFields(Class)
    */
   public JBBPDslBuilder AnnotatedClass(final Class<?> annotatedClass) {
     return addAnnotatedClass(annotatedClass, false);
   }
 
   /**
    * Add just fields of annotated class, outbound class will not be added as structure.
+   * <b>The Method allows to prepare script which will be able make mapping of field values</b>
    *
    * @param annotatedClass class to be converted into JBBP script, must not be null
    * @return the builder instance, must not be null
+   * @see com.igormaznitsa.jbbp.model.JBBPFieldStruct#mapTo
    * @see com.igormaznitsa.jbbp.mapper.Bin
+   * @see JBBPDslBuilder#AnnotatedClass(Class)
    */
   public JBBPDslBuilder AnnotatedClassFields(final Class<?> annotatedClass) {
     return addAnnotatedClass(annotatedClass, true);

jbbp/src/test/java/com/igormaznitsa/jbbp/it/BasedOnQuestionsAndCasesTest.java

@@ -33,6 +33,8 @@
 import com.igormaznitsa.jbbp.model.JBBPFieldLong;
 import com.igormaznitsa.jbbp.model.JBBPFieldStruct;
 import com.igormaznitsa.jbbp.model.JBBPNumericField;
+import com.igormaznitsa.jbbp.utils.JBBPDslBuilder;
+import com.igormaznitsa.jbbp.utils.JBBPTextWriter;
 import org.junit.jupiter.api.Test;
 
 import java.io.EOFException;
@@ -222,6 +224,22 @@ public void run() {
     assertEquals(0, errorCounter.get());
   }
 
+  @Test
+  public void testParseBitsThroughDslBasedScriptAndMapping() throws Exception {
+    class Bits {
+      @Bin(name = "a", type = BinType.BIT_ARRAY, outBitNumber = JBBPBitNumber.BITS_1, extra = "_")
+      byte[] bit;
+    }
+
+    JBBPParser parser = JBBPParser.prepare(JBBPDslBuilder.Begin().AnnotatedClassFields(Bits.class).End());
+
+    Bits parsed = parser.parse(new byte[] {73}).mapTo(Bits.class);
+
+    System.out.println(JBBPTextWriter.makeStrWriter().Bin(parsed).Close().toString());
+
+    assertArrayEquals(new byte[] {1, 0, 0, 1, 0, 0, 1, 0}, parsed.bit);
+  }
+
   /**
    * Case 10-aug-2017
    * NullPointer exception when referencing a JBBPCustomFieldTypeProcessor parsed field.