kezhenxu94 commented on a change in pull request #4555: Correlation protocol implement URL: https://github.com/apache/skywalking/pull/4555#discussion_r396902387
########## File path: apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/CorrelationContext.java ########## @@ -0,0 +1,150 @@ +/* + * 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.skywalking.apm.agent.core.context; + +import org.apache.skywalking.apm.agent.core.base64.Base64; +import org.apache.skywalking.apm.agent.core.conf.Config; +import org.apache.skywalking.apm.util.StringUtil; + +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.stream.Collectors; + +/** + * Correlation context, use to propagation user custom data. + * Working on the protocol and delegate set/get method. + */ +public class CorrelationContext { + + private final Map<String, String> data; + + public CorrelationContext() { + this.data = new HashMap<>(Config.Correlation.ELEMENT_MAX_NUMBER); + } + + public Optional<String> set(String key, String value) { + // key must not null + if (key == null) { + return Optional.empty(); + } + if (value == null) { + value = ""; + } Review comment: How do I remove a key if you consider a `null` as `""`. For example, if I already have 3 items in the context and I want to remove one of them and put another one (different `key`), there's no way to do so ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
