DATAMONGO-1146 - Added QueryDslMongoRepository.exists(…) which accepts a Querydsl predicate.

Added explicit test case for QueryDslMongoRepository.

Related tickets: DATACMNS-636.
Original pull request: spring-projects#270.

Author: Thomas Darimont

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepository.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2014 the original author or authors.
+ * Copyright 2011-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -161,6 +161,14 @@ public long count(Predicate predicate) {
 		return createQueryFor(predicate).count();
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.querydsl.QueryDslPredicateExecutor#exists(com.mysema.query.types.Predicate)
+	 */
+	public boolean exists(Predicate predicate) {
+		return createQueryFor(predicate).exists();
+	}
+
 	/**
 	 * Creates a {@link MongodbQuery} for the given {@link Predicate}.
 	 * 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/repository/support/QueryDslMongoRepositoryIntegrationTests.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.repository.support;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.util.Arrays;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.mongodb.core.MongoOperations;
+import org.springframework.data.mongodb.repository.Person;
+import org.springframework.data.mongodb.repository.QPerson;
+import org.springframework.data.mongodb.repository.query.MongoEntityInformation;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.mysema.query.types.Predicate;
+
+/**
+ * Integration test for {@link QueryDslMongoRepository}.
+ * 
+ * @author Thomas Darimont
+ */
+@ContextConfiguration(
+		locations = "/org/springframework/data/mongodb/repository/PersonRepositoryIntegrationTests-context.xml")
+@RunWith(SpringJUnit4ClassRunner.class)
+public class QueryDslMongoRepositoryIntegrationTests {
+
+	@Autowired MongoOperations operations;
+	QueryDslMongoRepository<Person, String> repository;
+
+	Person dave, oliver, carter;
+	QPerson person;
+
+	@Before
+	public void setup() {
+
+		MongoRepositoryFactory factory = new MongoRepositoryFactory(operations);
+		MongoEntityInformation<Person, String> entityInformation = factory.getEntityInformation(Person.class);
+		repository = new QueryDslMongoRepository<Person, String>(entityInformation, operations);
+
+		operations.dropCollection(Person.class);
+
+		dave = new Person("Dave", "Matthews", 42);
+		oliver = new Person("Oliver August", "Matthews", 4);
+		carter = new Person("Carter", "Beauford", 49);
+
+		person = new QPerson("person");
+
+		repository.save(Arrays.asList(oliver, dave, carter));
+	}
+
+	/**
+	 * @see DATAMONGO-1146
+	 */
+	@Test
+	public void shouldSupportExistsWithPredicate() throws Exception {
+
+		assertThat(repository.exists(person.firstname.eq("Dave")), is(true));
+		assertThat(repository.exists(person.firstname.eq("Unknown")), is(false));
+		assertThat(repository.exists((Predicate) null), is(true));
+	}
+}