![\"\"](\"https:\/\/www.couchbase.com\/blog\/wp-content\/uploads\/2018\/06\/Screen-Shot-2018-06-04-at-10.34.39-PM-1024x252.png\")
<\/p>\nLast year I started learning Kotlin and I was surprised at how easy it was to convert a Java application. IntelliJ and a few other IDEs offer nice tools for automatic conversion, and with a few adjustments you can end up with a much more concise and less error-prone code.<\/p>\n
<\/p>\n
So, I decided to create a sample application to show my new favorite combination: Kotlin, Spring Boot, Spring Data, and Couchbase<\/a>:<\/p>\n You can clone the whole project here:<\/p>\n https:\/\/github.com\/couchbaselabs\/try-cb-kotlin<\/a><\/p>\n Let\u2019s start by creating our main class:<\/p>\n \u00a0Note:<\/strong> You class must be open<\/strong> otherwise you will end up with the following error:<\/p>\n Here is our User entity, it is very similar to the Java one<\/a>:<\/p>\n Mapping attributes in Couchbase are really simple. They will be directly mapped to the correspondent structure in JSON:<\/p>\n <\/p>\n Now, let\u2019s take a look at how our repository will look like:<\/p>\n <\/p>\nCreating a User Profile Service <\/strong><\/h2>\n
@SpringBootApplication\r\nopen class KotlinDemoApplication\r\n\r\nfun main(args: Array<String>) {\r\n SpringApplication.run(KotlinDemoApplication::class.java, *args)\r\n}<\/pre>\norg.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: @Configuration class 'KotlinDemoApplication' may not be final. Remove the final modifier to continue.\r\nOffending resource: com.couchbase.KotlinDemoApplication\r\n\tat org.springframework.beans.factory.parsing.FailFastProblemReporter.error(FailFastProblemReporter.java:70) ~[spring-beans-4.3.13.RELEASE.jar:4.3.13.RELEASE]\r\n\tat org.springframework.context.annotation.ConfigurationClass.validate(ConfigurationClass.java:214) ~[spring-context-4.3.13.RELEASE.jar:4.3.13.RELEASE]\r\n<\/pre>\n
@Document\r\nclass User(): BasicEntity() {\r\n\r\n constructor(id: String,\r\n name: String,\r\n address: Address,\r\n preferences: List<Preference>,\r\n securityRoles: List<String>): this(){\r\n\r\n this.id = id;\r\n this.name = name;\r\n this.address = address;\r\n this.preferences = preferences;\r\n this.securityRoles = securityRoles;\r\n }\r\n\r\n @Id\r\n var id: String? = null\r\n\r\n @NotNull\r\n var name: String? = null\r\n\r\n @Field\r\n var address: Address? = null\r\n\r\n @Field\r\n var preferences: List<Preference> = emptyList()\r\n\r\n @Field\r\n var securityRoles: List<String> = emptyList()\r\n}<\/pre>\n\n
\n
{\r\n \"id\": \"user::1\",\r\n \"name\": \"Denis Rosa\"\r\n}<\/pre>\n\n
{\r\n \"securityRoles\": [\"admin\", \"user\"]\r\n}<\/pre>\n\n
{ \r\n \"id\":\"user::1\",\r\n \"name\":\"Denis Rosa\",\r\n \"address\":{ \r\n \"streetName\":\"A Street Somewhere\",\r\n \"houseNumber\":\"42\",\r\n \"postalCode\":\"81234\",\r\n \"city\":\"Munich\",\r\n \"country\":\"DE\"\r\n },\r\n \"preferences\":[ \r\n { \r\n \"name\":\"lang\",\r\n \"value\":\"EN\"\r\n }\r\n ],\r\n \"securityRoles\":[ \r\n \"admin\",\r\n \"user\"\r\n ]\r\n}<\/pre>\nRepositories<\/strong><\/h2>\n
@N1qlPrimaryIndexed\r\n@ViewIndexed(designDoc = \"user\")\r\ninterface UserRepository : CouchbasePagingAndSortingRepository<User, String> {\r\n\r\n fun findByName(name: String): List<User>\r\n\r\n @Query(\"#{#n1ql.selectEntity} where #{#n1ql.filter} and ANY preference IN \" + \" preferences SATISFIES preference.name = $1 END\")\r\n fun findUsersByPreferenceName(name: String): List<User>\r\n\r\n @Query(\"#{#n1ql.selectEntity} where #{#n1ql.filter} and meta().id = $1 and ARRAY_CONTAINS(securityRoles, $2)\")\r\n fun hasRole(userId: String, role: String): User\r\n}<\/pre>\n\n