io.virtdata.functional.ThreadNumToLong Maven / Gradle / Ivy
/*
*
* Copyright 2015 Jonathan Shook
*
* 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 io.virtdata.functional;
import java.util.function.LongUnaryOperator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Matches a digit sequence in the current thread name and caches it in a thread local.
* This allows you to use any intentionally indexed thread factories to provide an analogue for
* concurrency. Note that once the thread number is cached, it will not be refreshed. This means
* you can't change the thread name and get an updated value.
*/
public class ThreadNumToLong implements LongUnaryOperator {
private static final Pattern pattern = Pattern.compile("^.*?(\\d+).*$");
private ThreadLocal threadLocalInt = new ThreadLocal() {
@Override
protected Long initialValue() {
Matcher matcher = pattern.matcher(Thread.currentThread().getName());
if (matcher.matches()) {
return Long.valueOf(matcher.group(1));
} else {
throw new RuntimeException(
"Unable to match a digit sequence in thread name:" + Thread.currentThread().getName()
);
}
}
};
@Override
public long applyAsLong(long input) {
return threadLocalInt.get();
}
}