IonStructLite bugfixes

src/software/amazon/ion/UnknownSymbolException.java

@@ -29,10 +29,17 @@ public class UnknownSymbolException
     private static final long serialVersionUID = 1L;
 
     private final int mySid;
+    private final String myText;
 
     public UnknownSymbolException(int sid)
     {
         mySid = sid;
+        myText = null;
+    }
+    public UnknownSymbolException(String message)
+    {
+        myText = message;
+        mySid = 0;
     }
 
     public int getSid()
@@ -43,6 +50,10 @@ public int getSid()
     @Override
     public String getMessage()
     {
-        return "Unknown symbol text for $" + mySid;
+        if(myText == null) {
+            return "Unknown symbol text for $" + mySid;
+        } else {
+            return myText;
+        }
     }
 }

src/software/amazon/ion/impl/lite/IonStructLite.java

@@ -34,14 +34,14 @@
 import software.amazon.ion.impl.PrivateCurriedValueFactory;
 import software.amazon.ion.util.Equivalence;
 import java.util.Set;
+import software.amazon.ion.UnknownSymbolException;
 
 final class IonStructLite
     extends IonContainerLite
     implements IonStruct
 {
     private static final int HASH_SIGNATURE =
         IonType.STRUCT.toString().hashCode();
-
     // TODO amzn/ion-java#41: add support for _isOrdered
 
     IonStructLite(ContainerlessContext context, boolean isNull)
@@ -54,14 +54,13 @@ private IonStructLite(IonStructLite existing, IonContext context)
         super(existing, context, true);
         // field map can be shallow cloned due to it dealing with String and Integer
         // values - both of which are immutable constructs and so safe to retain as references
-        this._field_map = null == _field_map
-                                ? null
-                                : new HashMap<String, Integer>(existing._field_map);
+        this._field_map = null == existing._field_map ? null : new HashMap<String, Integer>(existing._field_map);
         this._field_map_duplicate_count = existing._field_map_duplicate_count;
+        this.hasNullFieldName = existing.hasNullFieldName;
     }
 
     private Map<String, Integer> _field_map;
-
+    private boolean hasNullFieldName = false;
 
     public int                      _field_map_duplicate_count;
 
@@ -402,9 +401,9 @@ public IonValue get(String fieldName)
         IonValue field;
 
         if (field_idx < 0) {
+            if(hasNullFieldName) throw new UnknownSymbolException("Unable to resolve fieldname due to null fields.");
             field = null;
-        }
-        else {
+        } else {
             field = get_child(field_idx);
         }
 
@@ -450,11 +449,6 @@ public boolean add(IonValue child)
     {
         // TODO validate in struct.setFieldName
         String text = child.getFieldNameSymbol().getText();
-        if (text != null)
-        {
-            validateFieldName(text);
-        }
-
         IonValueLite concrete = (IonValueLite) child;
         _add(text, concrete);
 
@@ -483,6 +477,7 @@ protected void handle(IonValue newValue)
      */
     private void _add(String fieldName, IonValueLite child)
     {
+        hasNullFieldName |= fieldName == null;
         int size = get_child_count();
 
         // add this to the Container child collection

test/software/amazon/ion/StructTest.java

@@ -22,6 +22,8 @@
 import java.util.Iterator;
 import java.util.ListIterator;
 import java.util.Random;
+
+import com.sun.org.apache.bcel.internal.classfile.Unknown;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -738,6 +740,21 @@ public void testMakeNullRemovesChildsContainer()
                    val.getContainer());
     }
 
+    @Test
+    public void testUnknownSymbolException()
+    {
+        String input = "$ion_symbol_table::{imports:[{name:\"foo\", version:1, max_id:1}]} { $10: \"Unknown symbol\"}";
+        IonDatagram dg = loader().load(input);
+        IonStruct val = (IonStruct) dg.get(0);
+        try {
+            val.get("z");
+            fail("Should've thrown UnknownSymbolException");
+        } catch (UnknownSymbolException e) { }
+        try {
+            val = system().clone(val);
+        } catch (UnknownSymbolException e) { }
+    }
+
     @Test
     public void testRemoveAfterClone()
     {