[英]how to create multiple instance of same type using google Guice
We have used Google Guice framework for dependency injection. 我们已经使用Google Guice框架进行依赖项注入。 I need to create multiple insatnce of an interface in java. 我需要在java中创建接口的多个insatnce。
The execution starts from here: KfhRecordValidator.java class in the below code: 执行从这里开始:下面代码中的KfhRecordValidator.java类:
public class KfhRecordValidator implements RequestHandler<Request, Response> {
public Response handleRequest(Request request, Context context)
{
// Resolve the necessary dependencies, and process the request.
Injector injector = Guice.createInjector(new
DependencyModule());
Processor processor =
injector.getInstance(Processor.class);
return processor.process(request, context);
}}
The process class is having reference of RecordValidationHelper class and the injection is through constructor. 流程类具有RecordValidationHelper类的引用,而注入是通过构造函数进行的。 IRecordValidationService.java is an interface that is having validate method. IRecordValidationService.java是具有validate方法的接口。
public interface IRecordValidationService {
void validate(Record record) throws ValidationException;}
class processor is having one method called process that is being called in RecordValidationHelper class. 类处理器具有一个称为process的方法,该方法在RecordValidationHelper类中被调用。
class Processor {
private final RecordValidationHelper recordValidationHelper;
@Inject
@SuppressWarnings({"WeakerAccess"})
public Processor(IRecordValidationService recordValidationService,
IRecordService<ErrorRecord> recordService,
S3UtilsInterface s3Utils, IEnvironmentVariableReader
environmentVariableReader) {
this.recordValidationHelper = new
RecordValidationHelper(recordValidationService);
this.errorRecordHelper = new
ErrorRecordHelper(recordService, environmentVariableReader);
}
public Response process(Request request, @SuppressWarnings("unused") Context context) {
// Validate records
List<LambdaRecord> records = recordValidationHelper.processRecords(request.getRecords());}
Class DependencyModule.java extneds AbstractModule class of Guice injection that is having configure method. DependencyModule.java类扩展了具有configure方法的Guice注入的AbstractModule类。
class DependencyModule extends AbstractModule {
@Override
protected void configure() {
String validationType = System.getenv("ValidationType");
validationType= validationType.toLowerCase(Locale.ENGLISH);
String valType[]= validationType.split(",");
int length= valType.length;
for(int i=0;i<length;i++){
switch(valType[i]){
case "json":
bind(IRecordValidationService.class).to(JsonValidationService.class);
break;
case "avro":
bind(IRecordValidationService.class).to(AvroSchemaValidationService.class);
break;
case "clientlogging":
bind(IRecordValidationService.class).to(ClientLoggingValidationService.class);
break;
case "servicelogs":
bind(IRecordValidationService.class).to(ServiceLoggingValidationService.class);
break;
default:
throw new UnsupportedOperationException(String.format("Encountered an unsupported ValidationType of '%s'.", valType[i]));
}
} } }
SO the issue is if I am getting validation type as AVRO, JSON then it will bind IRecordValidationService to respective JsonValidationService/AvroSchemaValidationService class. 所以问题是如果我要获取验证类型为AVRO,JSON,则它将IRecordValidationService绑定到相应的JsonValidationService / AvroSchemaValidationService类。 I need to create multiple instance for that but it supports only once instance at a time. 我需要为此创建多个实例,但一次仅支持一个实例。 Below is the RecordValidationHelper.java class 下面是RecordValidationHelper.java类
public class RecordValidationHelper extends AbstractModule { private final IRecordValidationService recordValidationService; 公共类RecordValidationHelper扩展AbstractModule {私有最终IRecordValidationService recordValidationService;
@Inject
public RecordValidationHelper(IRecordValidationService recordValidationService) {
this.recordValidationService = recordValidationService;
}
public List processRecords(List requestRecords) { List records = new ArrayList<>(); public List processRecords(List requestRecords){列表记录= new ArrayList <>();
for (RequestRecord record : requestRecords) {
try {
Record domainRecord = new Record();
domainRecord.setKey(record.getRecordId());
domainRecord.setValue(new String(Base64.getDecoder().decode(record.getData())));
// Use the injected logic to validate the record.
((IRecordValidationService)
recordValidationService).validate(domainRecord);}
catch (ValidationException ex) {}}}
return records;}
Anyone having any idea about how it should be implemented to get multiple instance suitable for this. 任何人都对如何实现它以获得适用于此的多个实例有任何想法。
@Named
bindings 使用@Named
绑定 In your DependencyModule
, bind using names: 在您的DependencyModule
,使用名称进行绑定:
bind(IRecordValidationService.class)
.annotatedWith(Names.named("json"))
.to(JsonValidationService.class);
bind(IRecordValidationService.class)
.annotatedWith(Names.named("avro"))
.to(AvroSchemaValidationService.class);
bind(IRecordValidationService.class)
.annotatedWith(Names.named("clientlogging"))
.to(ClientLoggingValidationService.class);
bind(IRecordValidationService.class)
.annotatedWith(Names.named("servicelogs"))
.to(ServiceLoggingValidationService.class);
Then in your injectee: 然后在您的注射剂中:
@Inject
public RecordValidationHelper(
@Named("json") IRecordValidationService jsonValidation,
@Named("avro") IRecordValidationService avroValidation,
@Named("clientlogging") IRecordValidationService clientLoggingValidation,
@Named("servicelogs") IRecordValidationService serviceLogsValidation,
) {
this.jsonValidation = jsonValidation;
this.avroValidation = avroValidation;
this.clientLoggingValidation = clientLoggingValidation;
this.serviceLogsValidation = serviceLogsValidation;
}
See Guice's BindingAnnotation wiki page for more info. 有关更多信息,请参见Guice的BindingAnnotation Wiki页面 。
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