package com.heiye.learn1;

public class ThreadLocalTest {
    //print方法
    static void print(String threadName) {
        //打印當(dāng)前線程本地內(nèi)存中LocalVariable變量的值
        System.out.println(threadName + ":" + localVariable.get());
        //清除當(dāng)前線程本地內(nèi)存中的localVariable變量值
        //localVariable.remove();
    }

    //創(chuàng)建ThreadLocal變量
    static ThreadLocal<String> localVariable = new ThreadLocal<>();

    public static void main(String[] args) {
        //創(chuàng)建線程threadOne
        Thread threadOne = new Thread(new Runnable() {
            @Override
            public void run() {
                //設(shè)置線程one變量localVariable值
                localVariable.set("threadOne local Variable");
                //調(diào)用打印函數(shù)
                print("threadOne");
                //打印本地變量值
                System.out.println("threadOne remove after" + ":" + localVariable.get());
            }
        });
        //創(chuàng)建線程threadTwo
        Thread threadTwo = new Thread(new Runnable() {
            @Override
            public void run() {
                //設(shè)置線程two變量localVariable值
                localVariable.set("threadTwo local Variable");
                //調(diào)用打印函數(shù)
                print("threadTwo");
                //打印本地變量值
                System.out.println("threadTwo remove after" + ":" + localVariable.get());
            }
        });

        threadOne.start();
        threadTwo.start();
    }
}

 //set
 public void set(T value) {
        //獲取當(dāng)前線程
        Thread t = Thread.currentThread();
        //將當(dāng)前線程作為key,到ThreadLocalMap取查找對(duì)應(yīng)的線程變量
        ThreadLocalMap map = getMap(t);
        //如果找到，則設(shè)置
        if (map != null)
            map.set(this, value);
        else //第一次調(diào)用就創(chuàng)建當(dāng)前線程所在的hashmap
            createMap(t, value);
    }

 //get
 public T get() {
        Thread t = Thread.currentThread();
        ThreadLocalMap map = getMap(t);
        if (map != null) {
            ThreadLocalMap.Entry e = map.getEntry(this);
            if (e != null) {
                @SuppressWarnings("unchecked")
                T result = (T)e.value;
                return result;
            }
        }
        return setInitialValue();
    }

 //remove
 public void remove() {
         ThreadLocalMap m = getMap(Thread.currentThread());
         if (m != null)
             m.remove(this);
     }