INT-4173 Add Query support for Mongo i-c-adapter

JIRA: https://jira.spring.io/browse/INT-4173

INT-4173 convert query-expression to BasicQuery - fix checkstyle violation

INT-4173 convert query-expression to BasicQuery - refactor. address CR comments

INT-4173 convert query-expression to BasicQuery - UT coverage, xsd attribute documentation

INT-4173 cr comments, refactoring, register mongo api package for int-mongo:inbound-channel-adapter query-expression

INT-4173: Documentation, address PR comments & checkstyle violations

Polishing code style and imports order

**Cherry-pick to 4.3.x**

Conflicts:
	spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/inbound/MongoDbMessageSourceTests.java

spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/inbound/MongoDbMessageSource.java

@@ -25,8 +25,10 @@ import org.springframework.data.mongodb.core.convert.MongoConverter;
 import org.springframework.data.mongodb.core.query.BasicQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.expression.Expression;
+import org.springframework.expression.TypeLocator;
 import org.springframework.expression.common.LiteralExpression;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
+import org.springframework.expression.spel.support.StandardTypeLocator;
 import org.springframework.integration.context.IntegrationObjectSupport;
 import org.springframework.integration.core.MessageSource;
 import org.springframework.integration.expression.ExpressionUtils;
@@ -55,11 +57,12 @@ import com.mongodb.DBObject;
  *
  * @author Amol Nayak
  * @author Oleg Zhurakousky
+ * @author Yaron Yamin
  *
  * @since 2.2
  */
 public class MongoDbMessageSource extends IntegrationObjectSupport
-				implements MessageSource<Object> {
+		implements MessageSource<Object> {
 
 	private final Expression queryExpression;
 
@@ -84,7 +87,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * which should resolve to a MongoDb 'query' string
 	 * (see http://www.mongodb.org/display/DOCS/Querying).
 	 * The 'queryExpression' will be evaluated on every call to the {@link #receive()} method.
-	 *
 	 * @param mongoDbFactory The mongodb factory.
 	 * @param queryExpression The query expression.
 	 */
@@ -102,7 +104,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * (see http://www.mongodb.org/display/DOCS/Querying).
 	 * It assumes that the {@link MongoOperations} is fully initialized and ready to be used.
 	 * The 'queryExpression' will be evaluated on every call to the {@link #receive()} method.
-	 *
 	 * @param mongoTemplate The mongo template.
 	 * @param queryExpression The query expression.
 	 */
@@ -119,7 +120,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * {@link MongoTemplate#find(Query, Class)} or {@link MongoTemplate#findOne(Query, Class)}
 	 * method.
 	 * Default is {@link DBObject}.
-	 *
 	 * @param entityClass The entity class.
 	 */
 	public void setEntityClass(Class<?> entityClass) {
@@ -134,7 +134,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * {@link #receive()} will use {@link MongoTemplate#findOne(Query, Class)},
 	 * and the payload of the returned {@link Message} will be the returned target Object of type
 	 * identified by {{@link #entityClass} instead of a List.
-	 *
 	 * @param expectSingleResult true if a single result is expected.
 	 */
 	public void setExpectSingleResult(boolean expectSingleResult) {
@@ -145,7 +144,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * Sets the SpEL {@link Expression} that should resolve to a collection name
 	 * used by the {@link Query}. The resulting collection name will be included
 	 * in the {@link MongoHeaders#COLLECTION_NAME} header.
-	 *
 	 * @param collectionNameExpression The collection name expression.
 	 */
 	public void setCollectionNameExpression(Expression collectionNameExpression) {
@@ -157,7 +155,6 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	 * Allows you to provide a custom {@link MongoConverter} used to assist in deserialization
 	 * data read from MongoDb. Only allowed if this instance was constructed with a
 	 * {@link MongoDbFactory}.
-	 *
 	 * @param mongoConverter The mongo converter.
 	 */
 	public void setMongoConverter(MongoConverter mongoConverter) {
@@ -174,8 +171,12 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	@Override
 	protected void onInit() throws Exception {
 		this.evaluationContext =
-					ExpressionUtils.createStandardEvaluationContext(this.getBeanFactory());
-
+				ExpressionUtils.createStandardEvaluationContext(this.getBeanFactory());
+		TypeLocator typeLocator = this.evaluationContext.getTypeLocator();
+		if (typeLocator instanceof StandardTypeLocator) {
+			//Register MongoDB query API package so FQCN can be avoided in query-expression.
+			((StandardTypeLocator) typeLocator).registerImport("org.springframework.data.mongodb.core.query");
+		}
 		if (this.mongoTemplate == null) {
 			this.mongoTemplate = new MongoTemplate(this.mongoDbFactory, this.mongoConverter);
 		}
@@ -194,7 +195,20 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 	public Message<Object> receive() {
 		Assert.isTrue(this.initialized, "This class is not yet initialized. Invoke its afterPropertiesSet() method");
 		Message<Object> message = null;
-		Query query = new BasicQuery(this.queryExpression.getValue(this.evaluationContext, String.class));
+		Object value = this.queryExpression.getValue(this.evaluationContext);
+		Assert.notNull(value, "'queryExpression' must not evaluate to null");
+		Query query;
+		if (value instanceof String) {
+			query = new BasicQuery((String) value);
+		}
+		else if (value instanceof Query) {
+			query = ((Query) value);
+		}
+		else {
+			throw new IllegalStateException("'queryExpression' must evaluate to String " +
+					"or org.springframework.data.mongodb.core.query.Query");
+		}
+
 		Assert.notNull(query, "'queryExpression' must not evaluate to null");
 		String collectionName = this.collectionNameExpression.getValue(this.evaluationContext, String.class);
 		Assert.notNull(collectionName, "'collectionNameExpression' must not evaluate to null");
@@ -225,4 +239,5 @@ public class MongoDbMessageSource extends IntegrationObjectSupport
 
 		return message;
 	}
+
 }

spring-integration-mongodb/src/main/resources/org/springframework/integration/mongodb/config/spring-integration-mongodb-4.3.xsd

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <xsd:schema xmlns="http://www.springframework.org/schema/integration/mongodb"
-	xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:beans="http://www.springframework.org/schema/beans"
-	xmlns:tool="http://www.springframework.org/schema/tool"
-	xmlns:integration="http://www.springframework.org/schema/integration"
-	targetNamespace="http://www.springframework.org/schema/integration/mongodb"
-	elementFormDefault="qualified" attributeFormDefault="unqualified">
+			xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+			xmlns:tool="http://www.springframework.org/schema/tool"
+			xmlns:integration="http://www.springframework.org/schema/integration"
+			targetNamespace="http://www.springframework.org/schema/integration/mongodb"
+			elementFormDefault="qualified" attributeFormDefault="unqualified">
 
 	<xsd:import namespace="http://www.springframework.org/schema/beans" />
 	<xsd:import namespace="http://www.springframework.org/schema/integration"
@@ -45,9 +45,8 @@
 					<xsd:attribute name="query-expression" type="xsd:string">
 						<xsd:annotation>
 							<xsd:documentation>
-								SpEL expression which should resolve to a
-								String value identifying the
-								MongoDb Query. Also see 'query' attribute
+								SpEL expression which should resolve to a String query (please refer to the 'query' attribute),
+								or to an instance of MongoDb Query (e.q., query-expression="new BasicQuery('{''name'' : ''Bob''}').limit(2)").
 								This attribute is mutually exclusive with 'query' attribute.
 							</xsd:documentation>
 						</xsd:annotation>

spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/config/MongoDbInboundChannelAdapterIntegrationTests-context.xml

@@ -48,6 +48,25 @@
 										 auto-startup="false">
 		<int:poller fixed-rate="5000" />
 	</int-mongodb:inbound-channel-adapter>
+	<int-mongodb:inbound-channel-adapter id="mongoInboundAdapterWithStringQueryExpression"
+										 channel="replyChannel"
+										 collection-name="foo"
+										 mongo-template="mongoDbTemplate"
+										 query-expression="new String('{''name'' : ''Bob''}')"
+										 entity-class="java.lang.Object"
+										 auto-startup="false">
+		<int:poller fixed-rate="5000" />
+	</int-mongodb:inbound-channel-adapter>
+
+	<int-mongodb:inbound-channel-adapter id="mongoInboundAdapterWithQueryExpression"
+										 channel="replyChannel"
+										 collection-name="foo"
+										 mongo-template="mongoDbTemplate"
+										 query-expression="new BasicQuery('{''name'' : ''Bob''}').limit(1)"
+										 entity-class="java.lang.Object"
+										 auto-startup="false">
+		<int:poller fixed-rate="5000" />
+	</int-mongodb:inbound-channel-adapter>
 
 	<int-mongodb:inbound-channel-adapter id="mongoInboundAdapterWithNamedCollectionExpression"
 										 channel="replyChannel"

spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/config/MongoDbInboundChannelAdapterIntegrationTests.java

@@ -51,6 +51,7 @@ import com.mongodb.util.JSON;
 /**
  * @author Oleg Zhurakousky
  * @author Artem Bilan
+ * @author Yaron Yamin
  * @since 2.2
  */
 @ContextConfiguration
@@ -80,6 +81,14 @@ public class MongoDbInboundChannelAdapterIntegrationTests extends MongoDbAvailab
 	@Qualifier("mongoInboundAdapterWithNamedCollection")
 	private SourcePollingChannelAdapter mongoInboundAdapterWithNamedCollection;
 
+	@Autowired
+	@Qualifier("mongoInboundAdapterWithQueryExpression")
+	private SourcePollingChannelAdapter mongoInboundAdapterWithQueryExpression;
+
+	@Autowired
+	@Qualifier("mongoInboundAdapterWithStringQueryExpression")
+	private SourcePollingChannelAdapter mongoInboundAdapterWithStringQueryExpression;
+
 	@Autowired
 	@Qualifier("mongoInboundAdapterWithNamedCollectionExpression")
 	private SourcePollingChannelAdapter mongoInboundAdapterWithNamedCollectionExpression;
@@ -152,6 +161,30 @@ public class MongoDbInboundChannelAdapterIntegrationTests extends MongoDbAvailab
 
 		this.mongoInboundAdapterWithNamedCollection.stop();
 	}
+	@Test
+	@MongoDbAvailable
+	public void testWithQueryExpression() throws Exception {
+		this.mongoTemplate.save(this.createPerson("Bob"), "foo");
+		this.mongoTemplate.save(this.createPerson("Bob"), "foo");
+		this.mongoInboundAdapterWithQueryExpression.start();
+		@SuppressWarnings("unchecked")
+		Message<List<Person>> message = (Message<List<Person>>) replyChannel.receive(10000);
+		assertNotNull(message);
+		assertEquals(1, message.getPayload().size());
+		assertEquals("Bob", message.getPayload().get(0).getName());
+		this.mongoInboundAdapterWithQueryExpression.stop();
+	}
+	@Test
+	@MongoDbAvailable
+	public void testWithStringQueryExpression() throws Exception {
+		this.mongoTemplate.save(this.createPerson("Bob"), "foo");
+		this.mongoInboundAdapterWithStringQueryExpression.start();
+		@SuppressWarnings("unchecked")
+		Message<List<Person>> message = (Message<List<Person>>) replyChannel.receive(10000);
+		assertNotNull(message);
+		assertEquals("Bob", message.getPayload().get(0).getName());
+		this.mongoInboundAdapterWithStringQueryExpression.stop();
+	}
 
 	@Test
 	@MongoDbAvailable

spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/config/MongoDbInboundChannelAdapterParserTests-context.xml

@@ -1,11 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xmlns:int="http://www.springframework.org/schema/integration"
-	xmlns:int-mongodb="http://www.springframework.org/schema/integration/mongodb"
-	xmlns:mongo="http://www.springframework.org/schema/data/mongo"
-	xsi:schemaLocation="http://www.springframework.org/schema/data/mongo http://www.springframework.org/schema/data/mongo/spring-mongo.xsd
-		http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
+	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	   xmlns:int="http://www.springframework.org/schema/integration"
+	   xmlns:int-mongodb="http://www.springframework.org/schema/integration/mongodb"
+	   xsi:schemaLocation="http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
 		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 		http://www.springframework.org/schema/integration/mongodb http://www.springframework.org/schema/integration/mongodb/spring-integration-mongodb.xsd">
 
@@ -28,6 +26,33 @@
 		<int:poller fixed-rate="100"/>
 	</int-mongodb:inbound-channel-adapter>
 
+	<int-mongodb:inbound-channel-adapter id="fullConfigWithQueryExpression"
+						collection-name-expression="'foo'"
+						query-expression="new BasicQuery('{''address.state'' : ''PA''}').limit(2)"
+						mongo-converter="mongoConverter"
+						mongodb-factory="mongoDbFactory"
+						auto-startup="false">
+		<int:poller fixed-rate="100"/>
+	</int-mongodb:inbound-channel-adapter>
+
+	<int-mongodb:inbound-channel-adapter id="fullConfigWithSpelQuery"
+						collection-name-expression="'foo'"
+						query="{''address.state'' : ''PA''}"
+						mongo-converter="mongoConverter"
+						mongodb-factory="mongoDbFactory"
+						auto-startup="false">
+		<int:poller fixed-rate="100"/>
+	</int-mongodb:inbound-channel-adapter>
+
+	<int-mongodb:inbound-channel-adapter id="fullConfigWithQuery"
+										 collection-name-expression="'foo'"
+										 query="{'address.state' : 'PA'}"
+										 mongo-converter="mongoConverter"
+										 mongodb-factory="mongoDbFactory"
+										 auto-startup="false">
+		<int:poller fixed-rate="100"/>
+	</int-mongodb:inbound-channel-adapter>
+
 	<int-mongodb:inbound-channel-adapter id="fullConfigWithCollectionName"
 						collection-name="foo"
 						query="bar"

spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/config/MongoDbInboundChannelAdapterParserTests.java

@@ -23,7 +23,6 @@ import static org.junit.Assert.assertTrue;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
-
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
@@ -44,6 +43,7 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
  * @author Oleg Zhurakousky
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Yaron Yamin
  */
 @ContextConfiguration
 @RunWith(SpringJUnit4ClassRunner.class)
@@ -67,6 +67,18 @@ public class MongoDbInboundChannelAdapterParserTests {
 	@Qualifier("fullConfigWithCollectionExpression.adapter")
 	private SourcePollingChannelAdapter fullConfigWithCollectionExpressionAdapter;
 
+	@Autowired
+	@Qualifier("fullConfigWithQueryExpression.adapter")
+	private SourcePollingChannelAdapter fullConfigWithQueryExpressionAdapter;
+
+	@Autowired
+	@Qualifier("fullConfigWithQuery.adapter")
+	private SourcePollingChannelAdapter fullConfigWithQueryAdapter;
+
+	@Autowired
+	@Qualifier("fullConfigWithSpelQuery.adapter")
+	private SourcePollingChannelAdapter fullConfigWithSpelQueryAdapter;
+
 	@Autowired
 	@Qualifier("fullConfigWithCollectionName.adapter")
 	private SourcePollingChannelAdapter fullConfigWithCollectionNameAdapter;
@@ -90,28 +102,36 @@ public class MongoDbInboundChannelAdapterParserTests {
 
 	@Test
 	public void fullConfigWithCollectionExpression() {
-		MongoDbMessageSource source = TestUtils.getPropertyValue(this.fullConfigWithCollectionExpressionAdapter,
-				"source", MongoDbMessageSource.class);
-
-		assertEquals(false, TestUtils.getPropertyValue(this.fullConfigWithCollectionExpressionAdapter, "shouldTrack"));
-		assertNotNull(TestUtils.getPropertyValue(source, "mongoTemplate"));
-		assertEquals(this.mongoDbFactory, TestUtils.getPropertyValue(source, "mongoDbFactory"));
-		assertEquals(this.mongoConverter, TestUtils.getPropertyValue(source, "mongoConverter"));
-		assertNotNull(TestUtils.getPropertyValue(source, "evaluationContext"));
+		MongoDbMessageSource source = assertMongoDbMessageSource(this.fullConfigWithCollectionExpressionAdapter);
 		assertTrue(TestUtils.getPropertyValue(source, "collectionNameExpression") instanceof SpelExpression);
 		assertEquals("'foo'", TestUtils.getPropertyValue(source, "collectionNameExpression.expression"));
 	}
 
 	@Test
-	public void fullConfigWithCollectionName() {
-		MongoDbMessageSource source = TestUtils.getPropertyValue(this.fullConfigWithCollectionNameAdapter, "source",
-				MongoDbMessageSource.class);
+	public void fullConfigWithQueryExpression() {
+		MongoDbMessageSource source = assertMongoDbMessageSource(this.fullConfigWithQueryExpressionAdapter);
+		assertTrue(TestUtils.getPropertyValue(source, "queryExpression") instanceof SpelExpression);
+		assertEquals("new BasicQuery('{''address.state'' : ''PA''}').limit(2)",
+				TestUtils.getPropertyValue(source, "queryExpression.expression"));
+	}
 
-		assertEquals(false, TestUtils.getPropertyValue(this.fullConfigWithCollectionNameAdapter, "shouldTrack"));
-		assertNotNull(TestUtils.getPropertyValue(source, "mongoTemplate"));
-		assertEquals(this.mongoDbFactory, TestUtils.getPropertyValue(source, "mongoDbFactory"));
-		assertEquals(this.mongoConverter, TestUtils.getPropertyValue(source, "mongoConverter"));
-		assertNotNull(TestUtils.getPropertyValue(source, "evaluationContext"));
+	@Test
+	public void fullConfigWithSpelQuery() {
+		MongoDbMessageSource source = assertMongoDbMessageSource(this.fullConfigWithSpelQueryAdapter);
+		assertTrue(TestUtils.getPropertyValue(source, "queryExpression") instanceof LiteralExpression);
+		assertEquals("{''address.state'' : ''PA''}", TestUtils.getPropertyValue(source, "queryExpression.literalValue"));
+	}
+
+	@Test
+	public void fullConfigWithQuery() {
+		MongoDbMessageSource source = assertMongoDbMessageSource(this.fullConfigWithQueryAdapter);
+		assertTrue(TestUtils.getPropertyValue(source, "queryExpression") instanceof LiteralExpression);
+		assertEquals("{'address.state' : 'PA'}", TestUtils.getPropertyValue(source, "queryExpression.literalValue"));
+	}
+
+	@Test
+	public void fullConfigWithCollectionName() {
+		MongoDbMessageSource source = assertMongoDbMessageSource(this.fullConfigWithCollectionNameAdapter);
 		assertTrue(TestUtils.getPropertyValue(source, "collectionNameExpression") instanceof LiteralExpression);
 		assertEquals("foo", TestUtils.getPropertyValue(source, "collectionNameExpression.literalValue"));
 	}
@@ -141,4 +161,15 @@ public class MongoDbInboundChannelAdapterParserTests {
 				.close();
 	}
 
+	private MongoDbMessageSource assertMongoDbMessageSource(Object testedBean) {
+		MongoDbMessageSource source = TestUtils.getPropertyValue(testedBean, "source", MongoDbMessageSource.class);
+
+		assertEquals(false, TestUtils.getPropertyValue(testedBean, "shouldTrack"));
+		assertNotNull(TestUtils.getPropertyValue(source, "mongoTemplate"));
+		assertEquals(this.mongoDbFactory, TestUtils.getPropertyValue(source, "mongoDbFactory"));
+		assertEquals(this.mongoConverter, TestUtils.getPropertyValue(source, "mongoConverter"));
+		assertNotNull(TestUtils.getPropertyValue(source, "evaluationContext"));
+		return source;
+	}
+
 }

spring-integration-mongodb/src/test/java/org/springframework/integration/mongodb/inbound/MongoDbMessageSourceTests.java

@@ -36,6 +36,7 @@ import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.expression.Expression;
 import org.springframework.expression.common.LiteralExpression;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.integration.mongodb.rules.MongoDbAvailable;
 import org.springframework.integration.mongodb.rules.MongoDbAvailableTests;
 
@@ -46,11 +47,13 @@ import com.mongodb.util.JSON;
  * @author Amol Nayak
  * @author Oleg Zhurakousky
  * @author Gary Russell
+ * @author Yaron Yamin
  *
  * @since 2.2
  *
  */
 public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
+
 	/**
 	 * Tests by providing a null MongoDB Factory
 	 *
@@ -75,7 +78,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithSinigleElementIfOneInListAsDbObject() throws Exception {
+	public void validateSuccessfulQueryWithSingleElementIfOneInListAsDbObject() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -96,7 +99,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithSinigleElementIfOneInList() throws Exception {
+	public void validateSuccessfulQueryWithSingleElementIfOneInList() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -118,7 +121,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithSinigleElementIfOneInListAndSingleResult() throws Exception {
+	public void validateSuccessfulQueryWithSingleElementIfOneInListAndSingleResult() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -140,7 +143,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullSubObjectQueryWithSinigleElementIfOneInList() throws Exception {
+	public void validateSuccessfulSubObjectQueryWithSingleElementIfOneInList() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -161,8 +164,29 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithMultipleElements() throws Exception {
+	public void validateSuccessfulQueryWithMultipleElements() throws Exception {
+		List<Person> persons = queryMultipleElements(new LiteralExpression("{'address.state' : 'PA'}"));
+		assertEquals(3, persons.size());
+	}
 
+	@Test
+	@MongoDbAvailable
+	public void validateSuccessfulStringQueryExpressionWithMultipleElements() throws Exception {
+		List<Person> persons = queryMultipleElements(new SpelExpressionParser()
+				.parseExpression("\"{'address.state' : 'PA'}\""));
+		assertEquals(3, persons.size());
+	}
+
+	@Test
+	@MongoDbAvailable
+	public void validateSuccessfulBasicQueryExpressionWithMultipleElements() throws Exception {
+		List<Person> persons = queryMultipleElements(new SpelExpressionParser()
+				.parseExpression("new BasicQuery(\"{'address.state' : 'PA'}\").limit(2)"));
+		assertEquals(2, persons.size());
+	}
+
+	@SuppressWarnings("unchecked")
+	private List<Person> queryMultipleElements(Expression queryExpression) throws Exception {
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
 		MongoTemplate template = new MongoTemplate(mongoDbFactory);
@@ -170,18 +194,16 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 		template.save(this.createPerson("Moe"), "data");
 		template.save(this.createPerson("Jack"), "data");
 
-		Expression queryExpression = new LiteralExpression("{'address.state' : 'PA'}");
 		MongoDbMessageSource messageSource = new MongoDbMessageSource(mongoDbFactory, queryExpression);
 		messageSource.setBeanFactory(mock(BeanFactory.class));
 		messageSource.afterPropertiesSet();
-		@SuppressWarnings("unchecked")
-		List<Person> persons = (List<Person>) messageSource.receive().getPayload();
-		assertEquals(3, persons.size());
+
+		return (List<Person>) messageSource.receive().getPayload();
 	}
 
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithNullReturn() throws Exception {
+	public void validateSuccessfulQueryWithNullReturn() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -200,7 +222,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 	@SuppressWarnings("unchecked")
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithCustomConverter() throws Exception {
+	public void validateSuccessfulQueryWithCustomConverter() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -226,7 +248,7 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 	@SuppressWarnings("unchecked")
 	@Test
 	@MongoDbAvailable
-	public void validateSuccessfullQueryWithMongoTemplate() throws Exception {
+	public void validateSuccessfulQueryWithMongoTemplate() throws Exception {
 
 		MongoDbFactory mongoDbFactory = this.prepareMongoFactory();
 
@@ -272,4 +294,5 @@ public class MongoDbMessageSourceTests extends MongoDbAvailableTests {
 		result = (DBObject) messageSource.receive().getPayload();
 		assertEquals(id, result.get("_id"));
 	}
+
 }

src/reference/asciidoc/mongodb.adoc

@@ -190,7 +190,8 @@ The _MongoDb Inbound Channel Adapter_ is a polling consumer that reads data from
 
 As you can see from the configuration above, you configure a _MongoDb Inbound Channel Adapter_ using the `inbound-channel-adapter` element, providing values for various attributes such as:
 
-* `query` or `query-expression` - a JSON query (see http://www.mongodb.org/display/DOCS/Querying[MongoDb Querying])
+* `query` - a JSON query (see http://www.mongodb.org/display/DOCS/Querying[MongoDb Querying])
+* `query-expression` - A SpEL expression that is evaluated to a JSON query String (as the `query` attribute above), or to an instance of `o.s.data.mongodb.core.query.Query`. Mutually exclusive with `query` attribute.
 * `entity-class` - the type of the payload object; if not supplied, a `com.mongodb.DBObject` will be returned.
 * `collection-name` or `collection-name-expression` - Identifies the name of the MongoDb collection to use.
 * `mongodb-factory` - reference to an instance of `o.s.data.mongodb.MongoDbFactory`
@@ -214,7 +215,7 @@ You can do this using Transaction Synchronization feature that was added with Sp
 ----
 <int-mongodb:inbound-channel-adapter id="mongoInboundAdapter"
     channel="replyChannel"
-    query="{'name' : 'Bob'}"
+    query-expression="new BasicQuery('{''name'' : ''Bob''}').limit(100)"
     entity-class="java.lang.Object"
     auto-startup="false">
         <int:poller fixed-rate="200" max-messages-per-poll="1">