org.apache.rocketmq.shaded.io.opentelemetry.context.ArrayBasedContext Maven / Gradle / Ivy
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
// Includes work from:
/*
* Copyright 2015 The gRPC Authors
*
* Licensed 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.rocketmq.shaded.io.opentelemetry.context;
import java.util.Arrays;
import javax.annotation.Nullable;
final class ArrayBasedContext implements Context {
private static final Context ROOT = new ArrayBasedContext(new Object[0]);
// Used by auto-instrumentation agent. Check with auto-instrumentation before making changes to
// this method.
//
// In particular, do not change this return type to DefaultContext because auto-instrumentation
// hijacks this method and returns a bridged implementation of Context.
//
// Ideally auto-instrumentation would hijack the public Context.root() instead of this
// method, but auto-instrumentation also needs to inject its own implementation of Context
// into the class loader at the same time, which causes a problem because injecting a class into
// the class loader automatically resolves its super classes (interfaces), which in this case is
// Context, which would be the same class (interface) being instrumented at that time,
// which would lead to the JVM throwing a LinkageError "attempted duplicate interface definition"
static Context root() {
return ROOT;
}
private final Object[] entries;
private ArrayBasedContext(Object[] entries) {
this.entries = entries;
}
@Override
@Nullable
public V get(ContextKey key) {
for (int i = 0; i < entries.length; i += 2) {
if (entries[i] == key) {
@SuppressWarnings("unchecked")
V result = (V) entries[i + 1];
return result;
}
}
return null;
}
@Override
public Context with(ContextKey key, V value) {
for (int i = 0; i < entries.length; i += 2) {
if (entries[i] == key) {
if (entries[i + 1] == value) {
return this;
}
Object[] newEntries = entries.clone();
newEntries[i + 1] = value;
return new ArrayBasedContext(newEntries);
}
}
Object[] newEntries = Arrays.copyOf(entries, entries.length + 2);
newEntries[newEntries.length - 2] = key;
newEntries[newEntries.length - 1] = value;
return new ArrayBasedContext(newEntries);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("{");
for (int i = 0; i < entries.length; i += 2) {
sb.append(entries[i]).append('=').append(entries[i + 1]).append(", ");
}
// get rid of that last pesky comma
if (sb.length() > 1) {
sb.setLength(sb.length() - 2);
}
sb.append('}');
return sb.toString();
}
}