{"id":13810,"date":"2022-10-18T10:34:58","date_gmt":"2022-10-18T17:34:58","guid":{"rendered":"https:\/\/www.couchbase.com\/blog\/?p=13810"},"modified":"2023-08-29T14:29:03","modified_gmt":"2023-08-29T21:29:03","slug":"couchbase-transaction-support-in-spring-data-couchbase","status":"publish","type":"post","link":"https:\/\/www.couchbase.com\/blog\/pt\/couchbase-transaction-support-in-spring-data-couchbase\/","title":{"rendered":"Suporte a transa\u00e7\u00f5es do Couchbase no Spring Data Couchbase"},"content":{"rendered":"

Suporte a transa\u00e7\u00f5es<\/a> foi adicionado recentemente aos SDKs do Couchbase. A partir de Spring Data Couchbase 5.0.0-M5<\/em>O suporte a transa\u00e7\u00f5es foi adicionado ao Dados do Spring Couchbase<\/a><\/span>. Neste blog, descreveremos como usar o Spring Data @Transactional<\/em> para aproveitar o Couchbase Transactions.<\/span>
\n<\/span>
\n<\/span>O base de dados de mola<\/em> cont\u00e9m um reposit\u00f3rio aplicativo de teste de dados de mola<\/em> que realiza transa\u00e7\u00f5es. Ele se baseia na amostra de viagem<\/em> em um servidor Couchbase local. (qualquer bucket com um \u00edndice prim\u00e1rio ser\u00e1 suficiente).<\/span><\/p>\n

git clone git@github.com:spring-projects\/spring-data-examples.git\r\ncd spring-data-examples\/couchbase\/transactions<\/pre>\n
Os beans que oferecem suporte ao gerenciamento de transa\u00e7\u00f5es foram adicionados ao AbstractCouchbaseConfiguration<\/em>. Para permitir que a classe de interceptador de transa\u00e7\u00f5es integrada seja substitu\u00edda pelo CouchbaseTransactionInterceptor, verifique se a seguinte linha est\u00e1 no arquivo application.properties<\/em> file:<\/span>
\n<\/span>
\n<\/span>application.properties<\/span><\/em><\/p>\n
spring.main.allow-bean-definition-overriding=true<\/pre>\n
A configura\u00e7\u00e3o da transa\u00e7\u00e3o pode ser modificada substituindo o configureEnvironment()<\/em> em sua classe que estende AbstractCouchbaseConfiguration<\/em>.  Aqui definimos o DurabilityLevel (n\u00edvel de durabilidade)<\/em> para NENHUM<\/em> para que possamos trabalhar em nosso cluster de n\u00f3 \u00fanico. <\/span>
\n<\/span>
\n<\/span>Config.java<\/span><\/em><\/p>\n
@Configuration\r\n@EnableCouchbaseRepositories({\"com.example.demo\"})\r\n@EnableTransactionManagement\r\npublic class Config extends AbstractCouchbaseConfiguration {\r\n\u2026\r\n\u00a0@Override\r\n\u00a0\u00a0public void configureEnvironment(ClusterEnvironment.Builder builder){\r\n\u00a0\u00a0\u00a0\u00a0builder.transactionsConfig(TransactionsConfig.durabilityLevel(DurabilityLevel.NONE));\r\n\u00a0\u00a0}<\/pre>\n
Na classe que os usar\u00e1, precisamos definir o modelo como de costume e uma refer\u00eancia ao objeto de servi\u00e7o. \u00c9 importante observar que o objeto @Autowired<\/em> preenche uma vari\u00e1vel com um objeto proxy. Esse \u00e9 um detalhe importante, pois os objetos proxy executam o processamento antes e depois de chamar o m\u00e9todo real. <\/span>A cria\u00e7\u00e3o direta do objeto de servi\u00e7o a partir de seu construtor far\u00e1 com que a anota\u00e7\u00e3o @Transactional n\u00e3o tenha efeito.<\/span><\/i>
\n<\/span>
\n<\/span>CmdRunner.java<\/span><\/em><\/p>\n
@Autowired CouchbaseTemplate template;\r\n@Autowired AirportGatesService airportGatesService;<\/pre>\n
O servi\u00e7o \u00e9 definido com um @Servi\u00e7o<\/em> anota\u00e7\u00e3o. O construtor recebe argumentos que s\u00e3o @Bean<\/em> de modo que a infraestrutura possa criar um objeto proxy para @Autowired<\/em>.<\/span>
\n<\/span>
\n<\/span>AirlineGateService.java<\/span><\/em><\/p>\n
@Service\r\npublic class AirlineGatesService {\r\n    CouchbaseTemplate template;\r\n    public AirlineGatesService(CouchbaseTemplate template) {\r\n      this.template = template;\r\n}<\/pre>\n
AirlineGateService.java<\/em> (continua\u00e7\u00e3o)<\/span><\/p>\n
\/\/ The @Transactional annotation results in the method of the proxy for the service executing this in a transaction\r\n@Transactional\r\npublic void transferGates(String fromId, String toId, int gatesToTransfer, RuntimeException exceptionToThrow) {\r\n    \/\/ Not necessary, but may wish to include this check to confirm this is actually in a transaction.\r\n    TransactionalSupport.checkForTransactionInThreadLocalStorage().map((h) -> {\r\n        if (!h.isPresent())\r\n            throw new RuntimeException(\"not in transaction!\");\r\n        return h;\r\n    });\r\n\r\n    AirlineGates fromAirlineGates = template.findById(AirlineGates.class).one(fromId);\r\n    AirlineGates toAirlineGates = template.findById(AirlineGates.class).one(toId);\r\n    toAirlineGates.gates += gatesToTransfer;\r\n    fromAirlineGates.gates -= gatesToTransfer;\r\n    template.save(fromAirlineGates);\r\n    \/\/ maybe simulate an error occurring after the fromAirlineGates doc has been saved\r\n    if(exceptionToThrow != null){\r\n        throw exceptionToThrow;\r\n    }\r\n    template.save(toAirlineGates);\r\n}<\/pre>\n
Agora use tudo o que constru\u00edmos:<\/span><\/p>\n
    \n
  1. salvar dois Port\u00f5es de companhias a\u00e9reas<\/em> documentos, cada um dos quais indica 200 port\u00f5es<\/span><\/li>\n
  2. verificar se eles foram salvos.<\/span><\/li>\n
  3. executar o transferGates()<\/em> m\u00e9todo do servi\u00e7o para transferir 50 port\u00f5es de uma companhia a\u00e9rea para outra em uma transa\u00e7\u00e3o.<\/span><\/li>\n
  4. verificar se a transfer\u00eancia foi realizada.<\/span><\/li>\n
  5. tentativa de execu\u00e7\u00e3o transferGates()<\/em> novamente, desta vez com uma exce\u00e7\u00e3o que ocorre ap\u00f3s o primeiro documento ter sido salvo. <\/span>
    \n<\/span>
    \n<\/span>CmdRunner.java<\/span><\/em><\/li>\n<\/ol>\n
    AirlineGates airlineGates1 = new AirlineGates(\"1\", \"JFK\", \"American Airlines\", Long.valueOf(200)); \/\/1\r\nAirlineGates airlineGates2 = new AirlineGates(\"2\", \"JFK\", \"Lufthansa\", Long.valueOf(200));\r\nAirlineGates saved1 = airlineGatesService.save(airlineGates1);\r\nAirlineGates saved2 = airlineGatesService.save(airlineGates2);\r\nAirlineGates found1 = airlineGatesService.findById(saved1.getId()); \/\/2\r\nAirlineGates found2 = airlineGatesService.findById(saved2.getId());\r\nSystem.err.println(\"found before transferGates: \" + found1);\r\nSystem.err.println(\"found before transferGates: \" + found2);\r\n\/\/ move 50 gates from airline1 to airline2\r\nint gatesToTransfer=50;\r\nairlineGatesService.transferGates(airlineGates1.getId(), airlineGates2.getId(), gatesToTransfer, null); \/\/3\r\nfound1 = airlineGatesService.findById(saved1.getId());\r\nfound2 = airlineGatesService.findById(saved2.getId());\r\nSystem.err.println(\"found after\u00a0 transferGates: \" + found1); \/\/4\r\nSystem.err.println(\"found after\u00a0 transferGates: \" + found2);\r\nAssert.isTrue(found1.getGates().equals(airlineGates1.getGates()-gatesToTransfer), \"should have transferred\");\r\nAssert.isTrue(found2.getGates().equals(airlineGates1.getGates()+gatesToTransfer), \"should have transferred\");\r\n\/\/ attempt to move 44 gates from airline1 to airline2, but it fails.\r\ntry {\r\n    \/\/ 5\r\n    airlineGatesService.transferGates(airlineGates1.getId(), airlineGates2.getId(), 44, new SimulateErrorException());\r\n} catch (RuntimeException rte) {\r\n    if (!(rte instanceof TransactionSystemUnambiguousException) && rte != null\r\n            && rte.getCause() instanceof SimulateErrorException) {\r\n        throw rte;\r\n    }\r\n}\r\nSystem.err.println(\"found after\u00a0 transferGates: \" + airlineGatesService.findById(airlineGates1.getId()));\r\nSystem.err.println(\"found after\u00a0 transferGates: \" + airlineGatesService.findById(airlineGates2.getId()));\r\nAssert.isTrue(found1.getGates().equals(airlineGates1.getGates()-gatesToTransfer), \"should be same as previous\");\r\nAssert.isTrue(found2.getGates().equals(airlineGates1.getGates()+gatesToTransfer), \"should be same as previous\");<\/pre>\n
    Como funciona:<\/span><\/p>\n