BankAccountWithStampedLock.java

package org.example.bankaccount;

import java.util.concurrent.locks.StampedLock;
import java.util.function.Supplier;

public class BankAccountWithStampedLock {

private final StampedLock stampedLock = new StampedLock();
    private BankAccount bankAccount;

    public BankAccountWithStampedLockV2(BankAccount bankAccount) {
        this.bankAccount = bankAccount;
    }

    public <T> T tryOptimisticRead(final Runnable runnable, final Supplier<T> processEntity) {
        var stamped = this.stampedLock.tryOptimisticRead();
        runnable.run(); //execute read
        if (!this.stampedLock.validate(stamped)) {
            stamped = this.stampedLock.readLock();
            try {
                runnable.run(); //execute read
            } finally {
                this.stampedLock.unlockRead(stamped);
            }
        }
        return processEntity.get();
    }

    public void deposit(double amount) {
        var stamped = this.stampedLock.writeLock();
        try {
            bankAccount.deposit(amount);
        } finally {
            this.stampedLock.unlockWrite(stamped);
        }
    }

    public void withdraw(double amount) {
        var stamped = this.stampedLock.writeLock();
        try {
            bankAccount.withdraw(amount);
        } finally {
            this.stampedLock.unlockWrite(stamped);
        }
    }

    public double getBalance() {
        return bankAccount.getBalance();
    }
}