Handle nested Pattern and Document in Criteria.equals(…).

Closes #3414
Original pull request: #3615.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java

@@ -20,8 +20,10 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Map.Entry;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -58,6 +60,7 @@
  * @author Christoph Strobl
  * @author Mark Paluch
  * @author Andreas Zink
+ * @author Clément Petit
  */
 public class Criteria implements CriteriaDefinition {
 
@@ -901,9 +904,9 @@ private boolean isEqual(Object left, Object right) {
 			return right == null;
 		}
 
-		if (Pattern.class.isInstance(left)) {
+		if (left instanceof Pattern) {
 
-			if (!Pattern.class.isInstance(right)) {
+			if (!(right instanceof Pattern)) {
 				return false;
 			}
 
@@ -914,6 +917,46 @@ private boolean isEqual(Object left, Object right) {
 					&& leftPattern.flags() == rightPattern.flags();
 		}
 
+		if (left instanceof Document) {
+			if (!(right instanceof Document)) {
+				return false;
+			}
+			Document leftDocument = (Document) left;
+			Document rightDocument = (Document) right;
+			Iterator leftIterator = leftDocument.entrySet().iterator();
+			Iterator rightIterator = rightDocument.entrySet().iterator();
+
+			while (leftIterator.hasNext() && rightIterator.hasNext()) {
+				Map.Entry leftEntry = (Map.Entry)leftIterator.next();
+				Map.Entry rightEntry = (Map.Entry)rightIterator.next();
+				if (!isEqual(leftEntry.getKey(), rightEntry.getKey())) {
+					return false;
+				}
+				if (!isEqual(leftEntry.getValue(), rightEntry.getValue())) {
+					return false;
+				}
+			}
+			return !leftIterator.hasNext() && !rightIterator.hasNext();
+		}
+
+		if (Collection.class.isAssignableFrom(left.getClass())) {
+			if (!Collection.class.isAssignableFrom(right.getClass())) {
+				return false;
+			}
+
+			Collection leftCollection = (Collection) left;
+			Collection rightCollection = (Collection) right;
+			Iterator leftIterator = leftCollection.iterator();
+			Iterator rightIterator = rightCollection.iterator();
+
+			while (leftIterator.hasNext() && rightIterator.hasNext()) {
+				if (!isEqual(leftIterator.next(), rightIterator.next())) {
+					return false;
+				}
+			}
+			return !leftIterator.hasNext() && !rightIterator.hasNext();
+		}
+
 		return ObjectUtils.nullSafeEquals(left, right);
 	}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/query/CriteriaUnitTests.java

@@ -34,6 +34,7 @@
  * @author Thomas Darimont
  * @author Christoph Strobl
  * @author Andreas Zink
+ * @author Clément Petit
  */
 public class CriteriaUnitTests {
 
@@ -310,9 +311,33 @@ public void shouldAppendBitsAnySetWithPositionListCorrectly() {
 	@Test // DATAMONGO-2002
 	public void shouldEqualForSamePattern() {
 
+		Criteria left = new Criteria("field").regex("foo");
+		Criteria right = new Criteria("field").regex("foo");
+
+		assertThat(left).isEqualTo(right);
+	}
+
+	@Test // DATAMONGO-2002
+	public void shouldEqualForSamePatternAndFlags() {
+
 		Criteria left = new Criteria("field").regex("foo", "iu");
 		Criteria right = new Criteria("field").regex("foo");
 
 		assertThat(left).isNotEqualTo(right);
 	}
+
+	@Test // GH-3414
+	public void shouldEqualForNestedPattern() {
+
+		Criteria left = new Criteria("a").orOperator(
+			new Criteria("foo").regex("value", "i"),
+			new Criteria("bar").regex("value")
+		);
+		Criteria right = new Criteria("a").orOperator(
+			new Criteria("foo").regex("value", "i"),
+			new Criteria("bar").regex("value")
+		);
+
+		assertThat(left).isEqualTo(right);
+	}
 }