Package zipkin2.storage

Class ForwardingStorageComponent

java.lang.Object

zipkin2.Component

zipkin2.storage.StorageComponent

zipkin2.storage.ForwardingStorageComponent

All Implemented Interfaces:

Closeable, AutoCloseable

public abstract class ForwardingStorageComponent
extends StorageComponent

We provide a forwarding variant of the storage component for use cases such as trace decoration, or throttling.

Extending this is better than extending StorageComponent directly because it reduces risk of accidentally masking new methods. For example, if you extended storage component and later a new feature for cache control was added, that feature would be blocked until the wrapper was re-compiled. Such would be worse in most cases than not having decoration on new methods.

Since:

2.16

Nested Class Summary

Nested classes/interfaces inherited from class zipkin2.storage.StorageComponent

StorageComponent.Builder

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ForwardingStorageComponent()	Constructor for use by subclasses.

Method Summary

Modifier and Type	Method	Description
AutocompleteTags	autocompleteTags()
CheckResult	check()	Answers the question: Are operations on this component likely to succeed?
void	close()	Closes any network resources created implicitly by the component.
protected abstract StorageComponent	delegate()	The delegate is a method as opposed to a field, to allow for flexibility.
boolean	isOverCapacity(Throwable e)	A storage request failed and was dropped due to a limit, resource unavailability, or a timeout.
ServiceAndSpanNames	serviceAndSpanNames()
SpanConsumer	spanConsumer()
SpanStore	spanStore()
String	toString()
Traces	traces()

Methods inherited from class java.lang.Object

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

Constructor Details

ForwardingStorageComponent

protected ForwardingStorageComponent()

Constructor for use by subclasses.

Method Details

delegate

protected abstract StorageComponent delegate()

The delegate is a method as opposed to a field, to allow for flexibility. For example, this allows you to choose to make a final or lazy field, or no field at all.

spanConsumer

public SpanConsumer spanConsumer()

Specified by:

spanConsumer in class StorageComponent

traces

public Traces traces()

Overrides:

traces in class StorageComponent

spanStore

public SpanStore spanStore()

Specified by:

spanStore in class StorageComponent

autocompleteTags

public AutocompleteTags autocompleteTags()

Overrides:

autocompleteTags in class StorageComponent

serviceAndSpanNames

public ServiceAndSpanNames serviceAndSpanNames()

Overrides:

serviceAndSpanNames in class StorageComponent

check

public CheckResult check()

Description copied from class: Component

Answers the question: Are operations on this component likely to succeed?

Implementations should initialize the component if necessary. It should test a remote connection, or consult a trusted source to derive the result. They should use least resources possible to establish a meaningful result, and be safe to call many times, even concurrently.

Overrides:

check in class Component

See Also:

CheckResult.OK

isOverCapacity

public boolean isOverCapacity(Throwable e)

Description copied from class: StorageComponent

A storage request failed and was dropped due to a limit, resource unavailability, or a timeout. Implementations of throttling can use this signal to differentiate between failures, for example to reduce traffic.

Callers of this method will submit an exception raised by Call.execute() or on the error callback of Call.enqueue(Callback).

By default, this returns true if the input is a RejectedExecutionException. When originating exceptions, use this type to indicate a load related failure.

It is generally preferred to specialize this method to handle relevant exceptions for the particular storage rather than wrapping them in RejectedExecutionException at call sites. Extra wrapping can make errors harder to read, for example, by making it harder to "google" a solution for a well known error message for the storage client, instead thinking the error is in Zipkin code itself.

See also

While implementation is flexible, one known use is Netflix concurrency limits

Overrides:

isOverCapacity in class StorageComponent

close

public void close() throws IOException

Description copied from class: Component

Closes any network resources created implicitly by the component.

For example, if this created a connection, it would close it. If it was provided one, this would close any sessions, but leave the connection open.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class Component

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object