org.apache.hadoop.hive.ql.util.CloseableThreadLocal Maven / Gradle / Ivy
/*
* 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.hadoop.hive.ql.util;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class has similar functionality as {@link ThreadLocal}.
* Plus it provides a close function to clean up resources in all threads where the resource was initialized.
* @param - type of resource, it must implement {@link AutoCloseable}
*/
public class CloseableThreadLocal {
private static final Logger LOG = LoggerFactory.getLogger(CloseableThreadLocal.class);
private final ConcurrentHashMap threadLocalMap;
private final Supplier initialValue;
public CloseableThreadLocal(Supplier initialValue, int poolSize) {
this.initialValue = initialValue;
threadLocalMap = new ConcurrentHashMap<>(poolSize);
}
public T get() {
return threadLocalMap.computeIfAbsent(Thread.currentThread(), thread -> initialValue.get());
}
public void close() {
threadLocalMap.values().forEach(this::closeQuietly);
}
private void closeQuietly(AutoCloseable autoCloseable) {
try {
autoCloseable.close();
} catch (Exception e) {
LOG.warn("Error while closing resource.", e);
}
}
}