Lock State Coordination Report

Acquire a reentrant lock several times and report its nested hold count.

Lock State Coordination Report

LockStateCoordinationReport.java

import java.util.concurrent.locks.ReentrantLock;

public class LockStateCoordinationReport {
    public static void main(String[] args) {
        int reentries = ;
        ReentrantLock lock = new ReentrantLock();
        int acquired = 0;

        for (int i = 0; i < 1 + reentries; i++) {
            if (lock.tryLock()) {
                acquired++;
            }
        }

        int hold = lock.getHoldCount();
        String status = hold <= 1 ? "held" : hold == 2 ? "nested" : "deep";

        for (int i = 0; i < acquired; i++) {
            lock.unlock();
        }

        System.out.println("reentries=" + reentries + " acquired=" + acquired + " hold=" + hold + " status=" + status);
    }
}

import java.util.concurrent.locks.ReentrantLock;

public class LockStateCoordinationReport {
    public static void main(String[] args) {
        int reentries = ;
        ReentrantLock lock = new ReentrantLock();
        int acquired = 0;

        for (int i = 0; i < 1 + reentries; i++) {
            if (lock.tryLock()) {
                acquired++;
            }
        }

        int hold = lock.getHoldCount();
        String status = hold <= 1 ? "held" : hold == 2 ? "nested" : "deep";

        for (int i = 0; i < acquired; i++) {
            lock.unlock();
        }

        System.out.println("reentries=" + reentries + " acquired=" + acquired + " hold=" + hold + " status=" + status);
    }
}

import java.util.concurrent.locks.ReentrantLock;

public class LockStateCoordinationReport {
    public static void main(String[] args) {
        int reentries = ;
        ReentrantLock lock = new ReentrantLock();
        int acquired = 0;

        for (int i = 0; i < 1 + reentries; i++) {
            if (lock.tryLock()) {
                acquired++;
            }
        }

        int hold = lock.getHoldCount();
        String status = hold <= 1 ? "held" : hold == 2 ? "nested" : "deep";

        for (int i = 0; i < acquired; i++) {
            lock.unlock();
        }

        System.out.println("reentries=" + reentries + " acquired=" + acquired + " hold=" + hold + " status=" + status);
    }
}

reentrant lock A `ReentrantLock` lets the same thread acquire it more than once and tracks a hold count, so the report shows how deeply the lock is nested.