Package org.apache.juneau.rest.server.tracing

Class NoOpTracerHook

java.lang.Object

org.apache.juneau.rest.server.tracing.NoOpTracerHook

All Implemented Interfaces:

TracerHook

public final class NoOpTracerHook
extends Object
implements TracerHook

Default TracerHook implementation that opens no spans and records nothing.

Used whenever no consumer-provided TracerHook bean is reachable from the RestContext's bean store. Ensures the TracerHook contract is always satisfied — the framework can call startSpan(RestRequest) unconditionally without a null-check, and the returned NoOpTracerHook.NoOpScope satisfies the close-in-finally contract with zero allocations.

Both INSTANCE and NoOpTracerHook.NoOpScope.INSTANCE are process-wide singletons; the startSpan(RestRequest) method returns the same scope reference for every call and JIT-inlines the no-op setters / close to empty method bodies.

Since:

10.0.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	NoOpTracerHook.NoOpScope	No-op Scope returned by NoOpTracerHook.

Field Summary

Fields

Modifier and Type	Field	Description
static final NoOpTracerHook	INSTANCE	Process-wide singleton instance.

Method Summary

Modifier and Type	Method	Description
Scope	startSpan(RestRequest request)	Opens a new span for the in-flight request.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.juneau.rest.server.tracing.TracerHook

inject, startSpan, startSpan

Field Details

INSTANCE

public static final NoOpTracerHook INSTANCE

Process-wide singleton instance.

Method Details

startSpan

public Scope startSpan(RestRequest request)

Description copied from interface: TracerHook

Opens a new span for the in-flight request.

Specified by:

startSpan in interface TracerHook

Parameters:

request - The in-flight RestRequest. Never null. Bridges may read headers for distributed-tracing context propagation (e.g. W3C traceparent / tracestate), the HTTP method, the path, etc. Bridges must not mutate the request.

Returns:

The opened Scope. Never null. Returning null is a contract violation — bridges that cannot open a span (e.g. because the trace context is invalid) should return NoOpTracerHook.NoOpScope.INSTANCE so the framework's close-in-finally contract still holds.