Package pl.morgwai.base.grpc.utils

Class BlockingResponseObserver<T>

java.lang.Object

pl.morgwai.base.grpc.utils.BlockingResponseObserver<T>

All Implemented Interfaces:

StreamObserver<T>

public class BlockingResponseObserver<T>
extends Object
implements StreamObserver<T>

Response observer for a client side that blocks until response is completed with either onCompleted() or onError(Throwable).

Typical usage:

var responseObserver = new BlockingResponseObserver<ResponseMessage>(response -> {
    // handle ResponseMessage response here...
});
myGrpcServiceStub.myRemoteProcedure(someRequest, responseObserver);
try {
    responseObserver.awaitCompletion();
    // continue positive flow here...
} catch (InterruptedException e) {  // often unreachable code
} catch (ErrorReportedException e) {
    Throwable reportedError = e.getCause();
    // handle error that was reported via onError(reportedError) here...
}
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BlockingResponseObserver.ErrorReportedException	Thrown by awaitCompletion(long).

Field Summary

Fields

Modifier and Type	Field	Description
protected Consumer<T>	responseHandler	Called by onNext(Object).

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BlockingResponseObserver()	Constructor for those who prefer to override onNext(Object) in a subclass instead of providing a lambda.
	BlockingResponseObserver(Consumer<T> responseHandler)	Initializes responseHandler.

Method Summary

Modifier and Type	Method	Description
void	awaitCompletion()	Calls awaitCompletion(0l).
boolean	awaitCompletion(long timeoutMillis)	Awaits up to timeoutMillis for onCompleted() or onError(Throwable) to be called.
Throwable	getError()	If onError(Throwable) has been called, returns its argument, otherwise null.
boolean	isCompleted()	Returns true if either onCompleted() or onError(Throwable) was called.
void	onCompleted()	Notifies the thread that called awaitCompletion(long).
void	onError(Throwable error)	Causes awaitCompletion(long) to throw a BlockingResponseObserver.ErrorReportedException.
void	onNext(T response)	Calls responseHandler.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

responseHandler

protected Consumer<T> responseHandler

Called by onNext(Object).

Constructor Detail

BlockingResponseObserver

public BlockingResponseObserver(Consumer<T> responseHandler)

Initializes responseHandler.

BlockingResponseObserver

protected BlockingResponseObserver()

Constructor for those who prefer to override onNext(Object) in a subclass instead of providing a lambda.

Method Detail

onNext

public void onNext(T response)

Calls responseHandler.

Specified by:

onNext in interface StreamObserver<T>

isCompleted

public boolean isCompleted()

Returns true if either onCompleted() or onError(Throwable) was called.

getError

public Throwable getError()

If onError(Throwable) has been called, returns its argument, otherwise null.

awaitCompletion

public boolean awaitCompletion(long timeoutMillis)
                        throws BlockingResponseObserver.ErrorReportedException,
                               InterruptedException

Awaits up to timeoutMillis for onCompleted() or onError(Throwable) to be called. If timeoutMillis is 0 then waits without a timeout.

Returns:

true if onCompleted() was called, false if timeout passed

Throws:

BlockingResponseObserver.ErrorReportedException - if onError(Throwable) was called. getCause() will return the throwable passed as argument.

InterruptedException

awaitCompletion

public void awaitCompletion()
                     throws BlockingResponseObserver.ErrorReportedException,
                            InterruptedException

Calls awaitCompletion(0l).

Throws:

BlockingResponseObserver.ErrorReportedException

InterruptedException

onCompleted

public void onCompleted()

Notifies the thread that called awaitCompletion(long).

Specified by:

onCompleted in interface StreamObserver<T>

onError

public void onError(Throwable error)

Causes awaitCompletion(long) to throw a BlockingResponseObserver.ErrorReportedException.

Specified by:

onError in interface StreamObserver<T>