import java.util.concurrent.atomic.AtomicInteger;

public class AtomicIntegerDefectDemo {
    public static void main(String[] args) {
        defectOfABA();
    }

    static void defectOfABA() {
        final AtomicInteger atomicInteger = new AtomicInteger(1);

        Thread coreThread = new Thread(
                () -> {
                    final int currentValue = atomicInteger.get();
                    System.out.println(Thread.currentThread().getName() + " ------ currentValue=" + currentValue);

                    // 这段目的：模拟处理其他业务花费的时间
                    try {
                        Thread.sleep(300);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    boolean casResult = atomicInteger.compareAndSet(1, 2);
                    System.out.println(Thread.currentThread().getName()
                            + " ------ currentValue=" + currentValue
                            + ", finalValue=" + atomicInteger.get()
                            + ", compareAndSet Result=" + casResult);
                }
        );
        coreThread.start();

        // 这段目的：为了让 coreThread 线程先跑起来
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Thread amateurThread = new Thread(
                () -> {
                    int currentValue = atomicInteger.get();
                    boolean casResult = atomicInteger.compareAndSet(1, 2);
                    System.out.println(Thread.currentThread().getName()
                            + " ------ currentValue=" + currentValue
                            + ", finalValue=" + atomicInteger.get()
                            + ", compareAndSet Result=" + casResult);

                    currentValue = atomicInteger.get();
                    casResult = atomicInteger.compareAndSet(2, 1);
                    System.out.println(Thread.currentThread().getName()
                            + " ------ currentValue=" + currentValue
                            + ", finalValue=" + atomicInteger.get()
                            + ", compareAndSet Result=" + casResult);
                }
        );
        amateurThread.start();
    }
}

public final int get() //获取当前的值
public final int getAndSet(int newValue)//获取当前的值，并设置新的值
public final int getAndIncrement()//获取当前的值，并自增
public final int getAndDecrement() //获取当前的值，并自减
public final int getAndAdd(int delta) //获取当前的值，并加上预期的值
boolean compareAndSet(int expect, int update) //如果输入的数值等于预期值，则以原子方式将该值设置为输入值（update）
public final void lazySet(int newValue)//最终设置为newValue,使用 lazySet 设置之后可能导致其他线程在之后的一小段时间内还是可以读到旧的值。

import java.util.concurrent.atomic.AtomicInteger;

public class AtomicIntegerTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int temvalue = 0;
		AtomicInteger i = new AtomicInteger(0);
		temvalue = i.getAndSet(3);
		System.out.println("temvalue:" + temvalue + ";  i:" + i);//temvalue:0;  i:3
		temvalue = i.getAndIncrement();
		System.out.println("temvalue:" + temvalue + ";  i:" + i);//temvalue:3;  i:4
		temvalue = i.getAndAdd(5);
		System.out.println("temvalue:" + temvalue + ";  i:" + i);//temvalue:4;  i:9
	}

}

class Test {
        private volatile int count = 0;
        //若要线程安全执行执行count++，需要加锁
        public synchronized void increment() {
                  count++;
        }

        public int getCount() {
                  return count;
        }
}

class Test2 {
        private AtomicInteger count = new AtomicInteger();

        public void increment() {
                  count.incrementAndGet();
        }
      //使用AtomicInteger之后，不需要加锁，也可以实现线程安全。
       public int getCount() {
                return count.get();
        }
}

// setup to use Unsafe.compareAndSwapInt for updates（更新操作时提供“比较并替换”的作用）
private static final Unsafe unsafe = Unsafe.getUnsafe();
private static final long valueOffset;

static {
    try {
        valueOffset = unsafe.objectFieldOffset
            (AtomicInteger.class.getDeclaredField("value"));
    } catch (Exception ex) { throw new Error(ex); }
}

private volatile int value;

public final int get(int i) //获取 index=i 位置元素的值
public final int getAndSet(int i, int newValue)//返回 index=i 位置的当前的值，并将其设置为新值：newValue
public final int getAndIncrement(int i)//获取 index=i 位置元素的值，并让该位置的元素自增
public final int getAndDecrement(int i) //获取 index=i 位置元素的值，并让该位置的元素自减
public final int getAndAdd(int i, int delta) //获取 index=i 位置元素的值，并加上预期的值
boolean compareAndSet(int i, int expect, int update) //如果输入的数值等于预期值，则以原子方式将 index=i 位置的元素值设置为输入值（update）
public final void lazySet(int i, int newValue)//最终 将index=i 位置的元素设置为newValue,使用 lazySet 设置之后可能导致其他线程在之后的一小段时间内还是可以读到旧的值。

import java.util.concurrent.atomic.AtomicIntegerArray;

public class AtomicIntegerArrayTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int temvalue = 0;
		int[] nums = { 1, 2, 3, 4, 5, 6 };
		AtomicIntegerArray i = new AtomicIntegerArray(nums);
		for (int j = 0; j < nums.length; j++) {
			System.out.println(i.get(j));
		}
		temvalue = i.getAndSet(0, 2);
		System.out.println("temvalue:" + temvalue + ";  i:" + i);
		temvalue = i.getAndIncrement(0);
		System.out.println("temvalue:" + temvalue + ";  i:" + i);
		temvalue = i.getAndAdd(0, 5);
		System.out.println("temvalue:" + temvalue + ";  i:" + i);
	}

}

import java.util.concurrent.atomic.AtomicReference;

public class AtomicReferenceTest {

	public static void main(String[] args) {
		AtomicReference<Person> ar = new AtomicReference<Person>();
		Person person = new Person("SnailClimb", 22);
		ar.set(person);
		Person updatePerson = new Person("Daisy", 20);
		ar.compareAndSet(person, updatePerson);

		System.out.println(ar.get().getName());
		System.out.println(ar.get().getAge());
	}
}

class Person {
	private String name;
	private int age;

	public Person(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

}

import java.util.concurrent.atomic.AtomicStampedReference;

public class AtomicStampedReferenceDemo {
    public static void main(String[] args) {
        // 实例化、取当前值和 stamp 值
        final Integer initialRef = 0, initialStamp = 0;
        final AtomicStampedReference<Integer> asr = new AtomicStampedReference<>(initialRef, initialStamp);
        System.out.println("currentValue=" + asr.getReference() + ", currentStamp=" + asr.getStamp());

        // compare and set
        final Integer newReference = 666, newStamp = 999;
        final boolean casResult = asr.compareAndSet(initialRef, newReference, initialStamp, newStamp);
        System.out.println("currentValue=" + asr.getReference()
                + ", currentStamp=" + asr.getStamp()
                + ", casResult=" + casResult);

        // 获取当前的值和当前的 stamp 值
        int[] arr = new int[1];
        final Integer currentValue = asr.get(arr);
        final int currentStamp = arr[0];
        System.out.println("currentValue=" + currentValue + ", currentStamp=" + currentStamp);

        // 单独设置 stamp 值
        final boolean attemptStampResult = asr.attemptStamp(newReference, 88);
        System.out.println("currentValue=" + asr.getReference()
                + ", currentStamp=" + asr.getStamp()
                + ", attemptStampResult=" + attemptStampResult);

        // 重新设置当前值和 stamp 值
        asr.set(initialRef, initialStamp);
        System.out.println("currentValue=" + asr.getReference() + ", currentStamp=" + asr.getStamp());

        // [不推荐使用，除非搞清楚注释的意思了] weak compare and set
        // 困惑！weakCompareAndSet 这个方法最终还是调用 compareAndSet 方法。[版本: jdk-8u191]
        // 但是注释上写着 "May fail spuriously and does not provide ordering guarantees,
        // so is only rarely an appropriate alternative to compareAndSet."
        // todo 感觉有可能是 jvm 通过方法名在 native 方法里面做了转发
        final boolean wCasResult = asr.weakCompareAndSet(initialRef, newReference, initialStamp, newStamp);
        System.out.println("currentValue=" + asr.getReference()
                + ", currentStamp=" + asr.getStamp()
                + ", wCasResult=" + wCasResult);
    }
}

import java.util.concurrent.atomic.AtomicMarkableReference;

public class AtomicMarkableReferenceDemo {
    public static void main(String[] args) {
        // 实例化、取当前值和 mark 值
        final Boolean initialRef = null, initialMark = false;
        final AtomicMarkableReference<Boolean> amr = new AtomicMarkableReference<>(initialRef, initialMark);
        System.out.println("currentValue=" + amr.getReference() + ", currentMark=" + amr.isMarked());

        // compare and set
        final Boolean newReference1 = true, newMark1 = true;
        final boolean casResult = amr.compareAndSet(initialRef, newReference1, initialMark, newMark1);
        System.out.println("currentValue=" + amr.getReference()
                + ", currentMark=" + amr.isMarked()
                + ", casResult=" + casResult);

        // 获取当前的值和当前的 mark 值
        boolean[] arr = new boolean[1];
        final Boolean currentValue = amr.get(arr);
        final boolean currentMark = arr[0];
        System.out.println("currentValue=" + currentValue + ", currentMark=" + currentMark);

        // 单独设置 mark 值
        final boolean attemptMarkResult = amr.attemptMark(newReference1, false);
        System.out.println("currentValue=" + amr.getReference()
                + ", currentMark=" + amr.isMarked()
                + ", attemptMarkResult=" + attemptMarkResult);

        // 重新设置当前值和 mark 值
        amr.set(initialRef, initialMark);
        System.out.println("currentValue=" + amr.getReference() + ", currentMark=" + amr.isMarked());

        // [不推荐使用，除非搞清楚注释的意思了] weak compare and set
        // 困惑！weakCompareAndSet 这个方法最终还是调用 compareAndSet 方法。[版本: jdk-8u191]
        // 但是注释上写着 "May fail spuriously and does not provide ordering guarantees,
        // so is only rarely an appropriate alternative to compareAndSet."
        // todo 感觉有可能是 jvm 通过方法名在 native 方法里面做了转发
        final boolean wCasResult = amr.weakCompareAndSet(initialRef, newReference1, initialMark, newMark1);
        System.out.println("currentValue=" + amr.getReference()
                + ", currentMark=" + amr.isMarked()
                + ", wCasResult=" + wCasResult);
    }
}

import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;

public class AtomicIntegerFieldUpdaterTest {
	public static void main(String[] args) {
		AtomicIntegerFieldUpdater<User> a = AtomicIntegerFieldUpdater.newUpdater(User.class, "age");

		User user = new User("Java", 22);
		System.out.println(a.getAndIncrement(user));// 22
		System.out.println(a.get(user));// 23
	}
}

class User {
	private String name;
	public volatile int age;

	public User(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

}