/*
* 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.cassandra.concurrent;
import org.apache.cassandra.service.ClientWarn;
import org.apache.cassandra.tracing.Tracing;
public interface ExecutorLocal<T>
{
ExecutorLocal[] all = { Tracing.instance, ClientWarn.instance };
/**
* This is called when scheduling the task, and also before calling {@link #set(Object)} when running on a
* executor thread.
*
* @return The thread-local value that we want to copy across executor boundaries; may be null if not set.
*/
T get();
/**
* Before a task has been run, this will be called with the value from the thread that scheduled the task, and after
* the task is finished, the value that was previously retrieved from this thread is restored.
*
* @param value Value to use for the executor local state; may be null.
*/
void set(T value);
}