1package org.springframework.cloud.sleuth; 2 3import org.checkerframework.checker.nullness.qual.Nullable; 4import org.springframework.cloud.sleuth.Sampler; 5import org.springframework.cloud.sleuth.Span; 6 7interface Tracer { 8 @Nullable Span close(@Nullable Span span); 9 @Nullable Span continueSpan(@Nullable Span span); 10 @Nullable Span createSpan(String name); 11 @Nullable Span createSpan(String name, @Nullable Sampler sampler); 12 @Nullable Span createSpan(String name, @Nullable Span parent); 13 @Nullable Span detach(@Nullable Span span); 14 @Nullable Span getCurrentSpan(); 15} 16 17class Span { 18 Span (Span span, @Nullable Span parent); 19} 20