visualizer/JTree: make subclasses of ObjectTreeNode handle null values (

#63)

framework/tst-self/dslabs/framework/testing/visualization/ObjectJTreeTest.java

@@ -28,9 +28,11 @@
 import dslabs.framework.testing.LocalAddress;
 import java.lang.reflect.Method;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.regex.Pattern;
 import javax.swing.JLabel;
 import lombok.EqualsAndHashCode;
@@ -132,6 +134,26 @@ public void diffTest() {
         f2.v03 = null;
         f2.v04 = new int[]{1, 2, 3, 4};
         f2.v05 = null;
+        f2.v06 = null;
+        f2.v06v1 = new LocalAddress(("jkjkjk"));
+        f2.v0not7v1 = null;
+        f2.v0not7v2 = new LinkedList<>() {
+            @Override
+            public String toString() {
+                return "[]";
+            }
+        };
+        f2.v08 = null;
+        f2.v09 = new Integer[]{17, 42};
+        f2.v11 = null;
+        f2.v12 = new HashMap<>();
+        f2.v12.put("a", 3);
+        f2.v12.put("b", 47);
+        f2.v13 = null;
+        f2.v14 = new HashSet<>();
+        f2.v14.add("a");
+        f2.v14.add("b");
+
 
         t.update(f2);
 
@@ -163,26 +185,42 @@ class Foo extends Node {
     int[] v04 = null;
     int[] v05 = new int[3];
     Address v06 = new LocalAddress("asdf");
+    Address v06v1 = null;
     List<Object> v07 = new LinkedList<>() {
         @Override
         public String toString() {
             return "[]";
         }
     };
+    // carefully avoid "v07" regex match in these field names because the tests
+    // look for that to match the previous field.
+    List<Object> v0not7v1 = new LinkedList<>() {
+        @Override
+        public String toString() {
+            return "[]";
+        }
+    };
+    List<Object> v0not7v2 = null;
 
     Integer[] v08 = new Integer[]{0, 5, 3};
     Integer[] v09 = null;
 
     Object[] v10 = new Object[]{"foo", 4, new int[]{1, 2, 3}};
 
     Map<String, Integer> v11 = new HashMap<>();
+    Map<String, Integer> v12 = null;
+    Set<String> v13 = new HashSet<>();
+    Set<String> v14 = null;
 
     {
         v07.add("qwerty");
         v07.add(9876);
 
         v11.put("lbskj", 78525);
         v11.put("asiudb", 98623578);
+
+        v13.add("wreuio");
+        v13.add("097");
     }
 
     protected Foo(@NonNull Address address) {

framework/tst/dslabs/framework/testing/visualization/JTrees.java

@@ -65,6 +65,7 @@
 import lombok.Setter;
 import lombok.SneakyThrows;
 import org.apache.commons.lang3.ClassUtils;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 import static dslabs.framework.testing.visualization.Utils.makeIcon;
 
@@ -140,7 +141,7 @@ void setTreeDisplayType(JTreeDisplayType jTreeDisplayType) {
  * Specialized JTree which displays arbitrary Java objects. These objects can be
  * arbitrarily nested and can even contain circular references. Objects are
  * expanded on demand. Objects given to a {@code JObjectTree} should not be
- * modified in any after creation of the tree.
+ * modified in any way after creation of the tree.
  */
 class ObjectJTree extends BaseJTree {
     private static class ObjectJTreeCellRenderer extends BaseJTreeCellRenderer {
@@ -295,11 +296,6 @@ static protected ObjectTreeNode createNode(Object value,
         @SneakyThrows
         static protected ObjectTreeNode createNode(Class<?> clz, Object value,
                                                    ObjectJTree tree) {
-            // Non-default tree nodes don't handle null values
-            if (value == null) {
-                return new DefaultObjectNode(null, tree);
-            }
-
             for (Class<?> c : NODE_TYPES_IN_PRIORITY_ORDER) {
                 if ((Boolean) c.getDeclaredMethod("canHandle", Class.class)
                                .invoke(null, clz)) {
@@ -353,7 +349,7 @@ enum DiffStatus {
         }
 
         private KeyInstance keyInstance;
-        @Getter(AccessLevel.PROTECTED) private Object valueObj;
+        @Getter(AccessLevel.PROTECTED) @Nullable private Object valueObj;
         private ObjectTreeNode diffTarget;
         private boolean isDiffed = false;
         private boolean hasExpanded = false;
@@ -751,6 +747,9 @@ static boolean canHandle(Class<?> clz) {
 
         @Override
         protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
+            if (valueObj() == null) {
+                return;
+            }
             for (Entry<?, ?> entry : ((Map<?, ?>) valueObj()).entrySet()) {
                 childAdder.accept(new DefaultChildKey(entry.getKey()),
                         new MapEntryNode(entry.getValue(), tree()));
@@ -816,6 +815,9 @@ public String renderKey() {
 
         @Override
         protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
+            if (valueObj() == null) {
+                return;
+            }
             int i = 0;
             for (Object item : (List<?>) valueObj()) {
                 childAdder.accept(new ListKey(i), createNode(item));
@@ -887,6 +889,9 @@ protected String treeCellTextInternal() {
         @Override
         protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
             Object o = valueObj();
+            if (o == null) {
+                return;
+            }
             int i = 0;
             if (o instanceof byte[]) {
                 for (byte item : (byte[]) valueObj()) {
@@ -967,6 +972,9 @@ public String renderKey() {
 
         @Override
         protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
+            if (valueObj() == null) {
+                return;
+            }
             for (Object item : (Set<?>) valueObj()) {
                 childAdder.accept(new SetKey(item), createNode(item));
             }
@@ -1011,8 +1019,8 @@ protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
 
         @Override
         protected String treeCellTextInternal() {
-            Class<?> primitiveClass =
-                    ClassUtils.wrapperToPrimitive(valueObj().getClass());
+            assert valueObj() != null;  // primitives cannot be null
+            Class<?> primitiveClass = ClassUtils.wrapperToPrimitive(valueObj().getClass());
 
             StringBuilder sb = new StringBuilder();
             if (keyObj() != null) {
@@ -1057,15 +1065,20 @@ protected void expand(BiConsumer<ChildKey, ObjectTreeNode> childAdder) {
 
         @Override
         protected String treeCellTextInternal() {
-            assert valueObj() != null && valueObj() instanceof Address;
+            assert valueObj() == null || valueObj() instanceof Address;
 
             StringBuilder sb = new StringBuilder();
             if (keyObj() != null) {
                 sb.append(renderKey());
             }
             sb.append(String.format("<font color='%s'>(Address)</font>",
                     secondaryColor()));
-            sb.append(valueObj());
+            if (valueObj() != null) {
+                sb.append(valueObj());
+            } else {
+                sb.append(String.format("<font color='%s'>null</font>",
+                        secondaryColor()));
+            }
 
             return sb.toString();
         }