com.uber.tchannel.tracing.TracingContext Maven / Gradle / Ivy
/*
* Copyright (c) 2015 Uber Technologies, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.uber.tchannel.tracing;
import io.opentracing.Span;
import java.util.EmptyStackException;
import java.util.Stack;
public interface TracingContext {
/**
* Push given span to the top of the stack.
*
* @param span new active span
*/
void pushSpan(Span span);
/**
* @return whether there is a current/active span at the top of the stack
*/
boolean hasSpan();
/**
* @return the current active span at the top of the stack, if any
* @throws EmptyStackException when no active span has been pushed to the stack
*/
Span currentSpan() throws EmptyStackException;
/**
* Remove the current active span from the top of the stack.
* The next span in the stack, if any, becomes current.
*
* @return the current span from the top of the stack
* @throws EmptyStackException when no active span has been pushed to the stack
*/
Span popSpan() throws EmptyStackException;
/**
* Remove all spans from stack.
*/
void clear();
/**
* Default implementation of TracingContext does not support in-process
* propagation and therefore does not store any spans.
*/
class Default implements TracingContext {
@Override
public void pushSpan(Span span) {
// do nothing
}
@Override
public boolean hasSpan() {
return false;
}
@Override
public Span currentSpan() {
throw new EmptyStackException();
}
@Override
public Span popSpan() throws EmptyStackException {
throw new EmptyStackException();
}
@Override
public void clear() {
// do nothing
}
}
class ThreadLocal implements TracingContext {
private final java.lang.ThreadLocal> stack =
new java.lang.ThreadLocal>() {
@Override
protected Stack initialValue() {
return new Stack<>();
}
};
private Stack stack() {
return stack.get();
}
@Override
public void pushSpan(Span span) {
stack().push(span);
}
@Override
public boolean hasSpan() {
return !stack().isEmpty();
}
@Override
public Span popSpan() {
return stack().pop();
}
@Override
public void clear() {
stack().clear();
}
@Override
public Span currentSpan() {
return stack().peek();
}
}
}