DATAMONGO-1777 - Pretty print Modifiers when calling Update.toString().

We now make sure to pretty print Update modifiers by safely rendering to a json representation including an optional $isolated opereator if applicable.
Along the way we also fix a flaw in PushOperationBuilder ignoring eg. $position when pushing single values.

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

@@ -109,7 +109,7 @@ public abstract class SerializationUtils {
 	 * printing raw {@link Document}s containing complex values before actually converting them into Mongo native types.
 	 *
 	 * @param value
-	 * @return
+	 * @return the serialized value or {@literal null}.
 	 */
 	@Nullable
 	public static String serializeToJsonSafely(@Nullable Object value) {
@@ -119,14 +119,15 @@ public abstract class SerializationUtils {
 		}
 
 		try {
-			return JSON.serialize(value);
+			return value instanceof Document ? ((Document) value).toJson() : JSON.serialize(value);
 		} catch (Exception e) {
+
 			if (value instanceof Collection) {
 				return toString((Collection<?>) value);
 			} else if (value instanceof Map) {
 				return toString((Map<?, ?>) value);
 			} else {
-				return String.format("{ $java : %s }", value.toString());
+				return String.format("{ \"$java\" : %s }", value.toString());
 			}
 		}
 	}

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

@@ -485,7 +485,14 @@ public class Update {
 	 */
 	@Override
 	public String toString() {
-		return SerializationUtils.serializeToJsonSafely(getUpdateObject());
+
+		Document doc = getUpdateObject();
+
+		if (isIsolated()) {
+			doc.append("$isolated", 1);
+		}
+
+		return SerializationUtils.serializeToJsonSafely(doc);
 	}
 
 	/**
@@ -510,7 +517,16 @@ public class Update {
 			this.modifiers.put(modifier.getKey(), modifier);
 		}
 
-		/* (non-Javadoc)
+		/**
+		 * @return true if no modifiers present.
+		 * @since 2.0
+		 */
+		public boolean isEmpty() {
+			return modifiers.isEmpty();
+		}
+
+		/*
+		 * (non-Javadoc)
 		 * @see java.lang.Object#hashCode()
 		 */
 		@Override
@@ -536,6 +552,11 @@ public class Update {
 
 			return this.modifiers.equals(that.modifiers);
 		}
+
+		@Override
+		public String toString() {
+			return SerializationUtils.serializeToJsonSafely(this.modifiers);
+		}
 	}
 
 	/**
@@ -554,6 +575,14 @@ public class Update {
 		 * @return value to be sent with command
 		 */
 		Object getValue();
+
+		/**
+		 * @return a safely serialized JSON representation.
+		 * @since 2.0
+		 */
+		default String toJsonString() {
+			return SerializationUtils.serializeToJsonSafely(Collections.singletonMap(getKey(), getValue()));
+		}
 	}
 
 	/**
@@ -627,6 +656,11 @@ public class Update {
 
 			return nullSafeEquals(values, ((Each) that).values);
 		}
+
+		@Override
+		public String toString() {
+			return toJsonString();
+		}
 	}
 
 	/**
@@ -652,6 +686,11 @@ public class Update {
 		public Object getValue() {
 			return position;
 		}
+
+		@Override
+		public String toString() {
+			return toJsonString();
+		}
 	}
 
 	/**
@@ -685,6 +724,11 @@ public class Update {
 		public Object getValue() {
 			return this.count;
 		}
+
+		@Override
+		public String toString() {
+			return toJsonString();
+		}
 	}
 
 	/**
@@ -746,6 +790,11 @@ public class Update {
 		public Object getValue() {
 			return this.sort;
 		}
+
+		@Override
+		public String toString() {
+			return toJsonString();
+		}
 	}
 
 	/**
@@ -867,7 +916,13 @@ public class Update {
 		 * @return never {@literal null}.
 		 */
 		public Update value(Object value) {
-			return Update.this.push(key, value);
+
+			if (this.modifiers.isEmpty()) {
+				return Update.this.push(key, value);
+			}
+
+			this.modifiers.addModifier(new Each(Collections.singletonList(value)));
+			return Update.this.push(key, this.modifiers);
 		}
 
 		/*

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

@@ -41,7 +41,7 @@ public class SerializationUtilsUnitTests {
 	public void writesSimpleDocument() {
 
 		Document document = new Document("foo", "bar");
-		assertThat(serializeToJsonSafely(document), is("{ \"foo\" : \"bar\"}"));
+		assertThat(serializeToJsonSafely(document), is("{ \"foo\" : \"bar\" }"));
 	}
 
 	@Test
@@ -49,7 +49,7 @@ public class SerializationUtilsUnitTests {
 
 		Document document = new Document("foo", new Complex());
 		assertThat(serializeToJsonSafely(document),
-				startsWith("{ \"foo\" : { $java : org.springframework.data.mongodb.core.SerializationUtilsUnitTests$Complex"));
+				startsWith("{ \"foo\" : { \"$java\" : org.springframework.data.mongodb.core.SerializationUtilsUnitTests$Complex"));
 	}
 
 	@Test
@@ -58,7 +58,7 @@ public class SerializationUtilsUnitTests {
 		Document document = new Document("foo", Arrays.asList("bar", new Complex()));
 		Matcher<String> expectedOutput = allOf(
 				startsWith(
-						"{ \"foo\" : [ \"bar\", { $java : org.springframework.data.mongodb.core.SerializationUtilsUnitTests$Complex"),
+						"{ \"foo\" : [ \"bar\", { \"$java\" : org.springframework.data.mongodb.core.SerializationUtilsUnitTests$Complex"),
 				endsWith(" } ] }"));
 		assertThat(serializeToJsonSafely(document), is(expectedOutput));
 	}

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

@@ -210,7 +210,7 @@ public class QueryTests {
 
 		Query query = new Query(where("name").is("foo")).restrict(SpecialDoc.class);
 		assertThat(query.toString(), is(
-				"Query: { \"name\" : \"foo\", \"_$RESTRICTED_TYPES\" : [ { $java : class org.springframework.data.mongodb.core.SpecialDoc } ] }, Fields: { }, Sort: { }"));
+				"Query: { \"name\" : \"foo\", \"_$RESTRICTED_TYPES\" : [ { \"$java\" : class org.springframework.data.mongodb.core.SpecialDoc } ] }, Fields: { }, Sort: { }"));
 		assertThat(query.getRestrictedTypes(), is(notNullValue()));
 		assertThat(query.getRestrictedTypes().size(), is(1));
 		assertThat(query.getRestrictedTypes(), hasItems(Arrays.asList(SpecialDoc.class).toArray(new Class<?>[0])));
@@ -221,7 +221,7 @@ public class QueryTests {
 
 		exception.expect(InvalidMongoDbApiUsageException.class);
 		exception.expectMessage("second 'value' criteria");
-		exception.expectMessage("already contains '{ \"value\" : { $java : VAL_1 } }'");
+		exception.expectMessage("already contains '{ \"value\" : { \"$java\" : VAL_1 } }'");
 
 		Query query = new Query();
 		query.addCriteria(where("value").is(EnumType.VAL_1));

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

@@ -26,6 +26,7 @@ import org.bson.Document;
 import org.joda.time.DateTime;
 import org.junit.Test;
 import org.springframework.data.mongodb.core.DocumentTestUtils;
+import org.springframework.data.mongodb.core.query.Update.Position;
 
 /**
  * Test cases for {@link Update}.
@@ -476,4 +477,18 @@ public class UpdateTests {
 		assertThat(update.getUpdateObject(),
 				equalTo(new Document("$min", new Document("key", date))));
 	}
+
+	@Test // DATAMONGO-1777
+	public void toStringShouldPrettyPrintModifiers() {
+
+		assertThat(new Update().push("key").atPosition(Position.FIRST).value("Arya").toString(), is(equalTo(
+				"{ \"$push\" : { \"key\" : { \"$java\" : { \"$position\" : { \"$java\" : { \"$position\" : 0} }, \"$each\" : { \"$java\" : { \"$each\" : [ \"Arya\"]} } } } } }")));
+	}
+
+	@Test // DATAMONGO-1777
+	public void toStringConsidersIsolated() {
+
+		assertThat(new Update().set("key", "value").isolated().toString(),
+				is(equalTo("{ \"$set\" : { \"key\" : \"value\" }, \"$isolated\" : 1 }")));
+	}
 }