JAVA-1192: Handle Map and List in BasicBSONObject.equals and hashCode

Author: jyemin

src/main/org/bson/BasicBSONObject.java

@@ -24,9 +24,11 @@
 import org.bson.types.BasicBSONList;
 import org.bson.types.ObjectId;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
@@ -339,12 +341,12 @@ public boolean equals( Object o ) {
             return false;
         }
 
-        return Arrays.equals(canonicalize(this).encode(), canonicalize(other).encode());
+        return Arrays.equals(canonicalizeBSONObject(this).encode(), canonicalizeBSONObject(other).encode());
     }
 
     @Override
     public int hashCode() {
-        return Arrays.hashCode(canonicalize(this).encode());
+        return Arrays.hashCode(canonicalizeBSONObject(this).encode());
     }
 
     private byte[] encode() {
@@ -356,15 +358,43 @@ private BSONObject decode(final byte[] encodedBytes) {
     }
 
     // create a copy of "from", but with keys ordered alphabetically
-    private static BasicBSONObject canonicalize(final BSONObject from) {
+    @SuppressWarnings("unchecked")
+    private static Object canonicalize(final Object from) {
+         if (from instanceof BSONObject && !(from instanceof BasicBSONList)) {
+             return canonicalizeBSONObject((BSONObject) from);
+         } else if (from instanceof List) {
+             return canonicalizeList((List<Object>) from);
+         } else if (from instanceof Map) {
+             return canonicalizeMap((Map<String, Object>) from);
+         } else {
+             return from;
+         }
+    }
+
+    private static Map<String, Object> canonicalizeMap(final Map<String, Object> from) {
+        Map<String, Object> canonicalized = new LinkedHashMap<String, Object>(from.size());
+        TreeSet<String> keysInOrder = new TreeSet<String>(from.keySet());
+        for (String key : keysInOrder) {
+            Object val = from.get(key);
+            canonicalized.put(key, canonicalize(val));
+        }
+        return canonicalized;
+    }
+
+    private static BasicBSONObject canonicalizeBSONObject(final BSONObject from) {
         BasicBSONObject canonicalized = new BasicBSONObject();
         TreeSet<String> keysInOrder = new TreeSet<String>(from.keySet());
         for (String key : keysInOrder) {
             Object val = from.get(key);
-            if (val instanceof BSONObject  && ! (val instanceof BasicBSONList)) {
-                val = canonicalize((BSONObject) val);
-            }
-            canonicalized.put(key, val);
+            canonicalized.put(key, canonicalize(val));
+        }
+        return canonicalized;
+    }
+
+    private static List canonicalizeList(final List<Object> list) {
+        List<Object> canonicalized = new ArrayList<Object>(list.size());
+        for (Object cur : list) {
+            canonicalized.add(canonicalize(cur));
         }
         return canonicalized;
     }

src/test/com/mongodb/BasicDBObjectTest.java

@@ -22,6 +22,9 @@
 import org.junit.Test;
 
 import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
 
 import static java.util.Arrays.asList;
 import static org.junit.Assert.assertEquals;
@@ -141,6 +144,21 @@ public void testEqualsAndHashCode() {
 
         assertEquality(new BasicDBObject("a", new BasicDBObject("y", 2).append("x", 1)),
                        new BasicDBObject("a", new BasicDBObject("x", 1).append("y", 2)));
+
+        assertEquality(new BasicDBObject("a", asList(new BasicDBObject("y", 2).append("x", 1))),
+                       new BasicDBObject("a", asList(new BasicDBObject("x", 1).append("y", 2))));
+
+        assertEquality(new BasicDBObject("a", new BasicDBList().put(1, new BasicDBObject("y", 2).append("x", 1))),
+                       new BasicDBObject("a", new BasicDBList().put(1, new BasicDBObject("x", 1).append("y", 2))));
+
+        Map<String, Object> first = new HashMap<String, Object>();
+        first.put("1", new BasicDBObject("y", 2).append("x", 1));
+        first.put("2", new BasicDBObject("a", 2).append("b", 1));
+        Map<String, Object> second = new TreeMap<String, Object>();
+        second.put("2", new BasicDBObject("b", 1).append("a", 2));
+        second.put("1", new BasicDBObject("x", 1).append("y", 2));
+
+        assertEquality(new BasicDBObject("a", first), new BasicDBObject("a", second));
     }
 
     void assertEquality(final BasicBSONObject x, final BasicBSONObject y) {