DATAMONGO-2119 - Allow SpEL usage for annotated $regex query.

Original pull request: #621.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/StringBasedMongoQuery.java

@@ -20,7 +20,9 @@ import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
 
+import org.bson.BSON;
 import org.bson.Document;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -37,6 +39,7 @@ import org.springframework.util.StringUtils;
 import com.mongodb.DBObject;
 import com.mongodb.DBRef;
 import com.mongodb.util.JSON;
+import com.mongodb.util.JSONCallback;
 
 /**
  * Query to use a plain JSON String to create the {@link Query} to actually execute.
@@ -224,7 +227,36 @@ public class StringBasedMongoQuery extends AbstractMongoQuery {
 			String transformedInput = transformQueryAndCollectExpressionParametersIntoBindings(input, bindings);
 			String parseableInput = makeParameterReferencesParseable(transformedInput);
 
-			collectParameterReferencesIntoBindings(bindings, JSON.parse(parseableInput));
+			collectParameterReferencesIntoBindings(bindings, JSON.parse(parseableInput, new JSONCallback() {
+
+				/*
+				 * (non-Javadoc)
+				 * @see com.mongodb.util.JSONCallback#objectDone()
+				 */
+				@Override
+				public Object objectDone() {
+					return exceptionSwallowingStackReducingObjectDone();
+				}
+
+				private Object exceptionSwallowingStackReducingObjectDone/*CauseWeJustNeedTheStructureNotTheActualValue*/() {
+
+					Object value;
+
+					try {
+						return super.objectDone();
+					} catch (PatternSyntaxException e) {
+						value = Pattern.compile("");
+					}
+
+					if (!isStackEmpty()) {
+						_put(curName(), value);
+					} else {
+						value = !BSON.hasDecodeHooks() ? value : BSON.applyDecodingHooks(value);
+						setRoot(value);
+					}
+					return value;
+				}
+			}));
 
 			return transformedInput;
 		}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/query/StringBasedMongoQueryUnitTests.java

@@ -590,6 +590,19 @@ public class StringBasedMongoQueryUnitTests {
 		assertThat(query.getQueryObject(), is(new Document("arg0", null)));
 	}
 
+	@Test // DATAMONGO-2119
+	public void spelShouldIgnoreJsonParseErrorsForRegex() {
+
+		StringBasedMongoQuery mongoQuery = createQueryForMethod("findByPersonLastnameRegex", Person.class);
+		ConvertingParameterAccessor accessor = StubParameterAccessor.getAccessor(converter,
+				new Person("Molly", "Chandler"));
+
+		org.springframework.data.mongodb.core.query.Query query = mongoQuery.createQuery(accessor);
+
+		assertThat(query.getQueryObject().toJson(),
+				is(new BasicQuery("{lastname: {$regex: 'Chandler'}}").getQueryObject().toJson()));
+	}
+
 	private StringBasedMongoQuery createQueryForMethod(String name, Class<?>... parameters) {
 
 		try {
@@ -697,10 +710,14 @@ public class StringBasedMongoQueryUnitTests {
 		@Query("{ 'arg0' : '?0', 'arg1' : '?1s' }")
 		List<Person> findByWhenQuotedAndSomeStuffAppended(String arg0, String arg1);
 
-		@Query("{ 'lastname' : { '$regex' : '^(?0|John ?1|?1)'} }") // use spel or some regex string this is fucking bad
+		@Query("{ 'lastname' : { '$regex' : '^(?0|John ?1|?1)'} }") // use spel or some regex string this is bad
 		Person findByLastnameRegex(String lastname, String alternative);
 
 		@Query("{ arg0 : ?#{[0]} }")
 		List<Person> findByUsingSpel(Object arg0);
+
+		@Query("{ 'lastname' : { '$regex' : ?#{[0].lastname} } }")
+		Person findByPersonLastnameRegex(Person key);
 	}
+
 }