| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.camel.opentracing; |
| |
| import io.opentracing.Span; |
| |
| import org.apache.camel.Exchange; |
| |
| /** |
| * Utility class for managing active spans as a stack associated with |
| * an exchange. |
| * |
| */ |
| public final class ActiveSpanManager { |
| |
| private static final String ACTIVE_SPAN_PROPERTY = "OpenTracing.activeSpan"; |
| |
| private ActiveSpanManager() { |
| } |
| |
| /** |
| * This method returns the current active span associated with the |
| * exchange. |
| * |
| * @param exchange The exchange |
| * @return The current active span, or null if none exists |
| */ |
| public static Span getSpan(Exchange exchange) { |
| Holder holder = (Holder) exchange.getProperty(ACTIVE_SPAN_PROPERTY); |
| if (holder != null) { |
| return holder.getSpan(); |
| } |
| return null; |
| } |
| |
| /** |
| * This method activates the supplied span for the supplied exchange. |
| * If an existing span is found for the exchange, this will be pushed |
| * onto a stack. |
| * |
| * @param exchange The exchange |
| * @param span The span |
| */ |
| public static void activate(Exchange exchange, Span span) { |
| exchange.setProperty(ACTIVE_SPAN_PROPERTY, |
| new Holder((Holder) exchange.getProperty(ACTIVE_SPAN_PROPERTY), span)); |
| } |
| |
| /** |
| * This method deactivates an existing active span associated with the |
| * supplied exchange. Once deactivated, if a parent span is found |
| * associated with the stack for the exchange, it will be restored |
| * as the current span for that exchange. |
| * |
| * @param exchange The exchange |
| */ |
| public static void deactivate(Exchange exchange) { |
| Holder holder = (Holder) exchange.getProperty(ACTIVE_SPAN_PROPERTY); |
| if (holder != null) { |
| exchange.setProperty(ACTIVE_SPAN_PROPERTY, holder.getParent()); |
| } |
| } |
| |
| /** |
| * Simple holder for the currently active span and an optional reference to |
| * the parent holder. This will be used to maintain a stack for spans, built |
| * up during the execution of a series of chained camel exchanges, and then |
| * unwound when the responses are processed. |
| * |
| */ |
| public static class Holder { |
| private Holder parent; |
| private Span span; |
| |
| public Holder(Holder parent, Span span) { |
| this.parent = parent; |
| this.span = span; |
| } |
| |
| public Holder getParent() { |
| return parent; |
| } |
| |
| public Span getSpan() { |
| return span; |
| } |
| } |
| } |