java 手写 jvm高性能缓存

package com.ws.commons.cache;

import java.time.localdatetime;
import java.time.format.datetimeformatter;
import java.util.arraylist;
import java.util.collections;
import java.util.iterator;
import java.util.linkedhashmap;
import java.util.list;
import java.util.map;
import java.util.map.entry;
import java.util.concurrent.concurrentlinkeddeque;
import java.util.concurrent.executorservice;
import java.util.concurrent.executors;
import java.util.concurrent.atomic.atomicinteger;

import com.ws.commons.tool.threadtool;

/**
 * 本地高性能缓存
 * 
 * @author 尘无尘
 *
 */
public class localcache implements icache {

    private static localcache staticinstance;

    public static localcache instance() {
        if (staticinstance != null) {
            return staticinstance;
        } else {
            synchronized (localcache.class) {
                if (staticinstance != null) {
                    return staticinstance;
                }
                staticinstance = new localcache();
                return staticinstance;
            }
        }
    }

    private localcache() {
    }

    /**
     * 缓存实例
     */
    private static final map<string, object> instance = collections.synchronizedmap(new linkedhashmap<>());

    /**
     * 缓存key 存储时间记录
     */
    private static final map<string, long> key_time_instance = collections.synchronizedmap(new linkedhashmap<>());

    /**
     * 时间格式化对象
     */
    public static final datetimeformatter yyyymmddhhmmss_fmt = datetimeformatter.ofpattern("yyyymmddhhmmss");

    /**
     * 存储最大数据数量，超出该数据量时，删除最新存储的数据
     */
    private static final int maxcount = 10000;

    /**
     * 清理缓存线程,防止频繁的缓存清理 创建线程消耗性能
     */
    private static final executorservice thread_pool = executors.newcachedthreadpool();

    /**
     * 清理缓存时线程做的标记
     */
    private static final atomicinteger tream_cache_flag = new atomicinteger(0);

    /**
     * 缓存清理 轮询一圈等待时长
     */
    private static final int trim_interim = 2000;

    /**
     * 队列存储，在末尾添加元素
     * 
     * @param key
     * @param value
     * @param outsecond 保存时间(秒)，超出时间，被清除
     */
    @suppresswarnings("unchecked")
    @override
    public void rightpush(string key, object value, int outsecond) {
        concurrentlinkeddeque<object> linklist = (concurrentlinkeddeque<object>) instance.get(key);
        if (linklist == null) {
            linklist = new concurrentlinkeddeque<>();
            instance.put(key, linklist);
        }
        key_time_instance.put(key,
                long.parselong(localdatetime.now().plusseconds(outsecond).format(yyyymmddhhmmss_fmt)));
        linklist.offer(value);
        localcache.streaminstance();
    }

    /**
     * 队列存储，在末尾添加元素
     * 
     * @param key
     * @param value
     */
    @suppresswarnings("unchecked")
    @override
    public void rightpush(string key, object value) {
        concurrentlinkeddeque<object> linklist = (concurrentlinkeddeque<object>) instance.get(key);
        if (linklist == null) {
            linklist = new concurrentlinkeddeque<>();
            instance.putifabsent(key, linklist);
        }
        linklist.offer(value);
        localcache.streaminstance();
    }

    /**
     * 队列存储，在开头添加元素
     * 
     * @param key
     * @param value
     */
    @suppresswarnings("unchecked")
    @override
    public void leftpush(string key, object value) {
        concurrentlinkeddeque<object> linklist = (concurrentlinkeddeque<object>) instance.get(key);
        if (linklist == null) {
            linklist = new concurrentlinkeddeque<>();
            instance.putifabsent(key, linklist);
        }
        linklist.offerfirst(value);
        localcache.streaminstance();
    }

    /**
     * 删除队列的最后一个元素
     * 
     * @param key
     * @return
     */
    @suppresswarnings("unchecked")
    @override
    public <t> t rightpop(string key) {
        concurrentlinkeddeque<object> linklist = (concurrentlinkeddeque<object>) instance.get(key);
        if (linklist == null) {
            return null;
        }
        return (t) linklist.polllast();
    }

    /**
     * 删除队列的第一个元素
     * 
     * @param key
     * @return
     */
    @suppresswarnings("unchecked")
    @override
    public <t> t leftpop(string key) {
        concurrentlinkeddeque<object> linklist = (concurrentlinkeddeque<object>) instance.get(key);
        if (linklist == null) {
            return null;
        }
        return (t) linklist.pollfirst();
    }

    /**
     * 
     * @param key
     * @param value
     */

    @override
    public void put(string key, object value) {
        instance.put(key, value);
        localcache.streaminstance();
    }

    /**
     * 
     * @param key
     * @param value
     * @param outsecond 保存时间(秒)，超出时间，被清除
     */
    @override
    public void put(string key, object value, int outsecond) {
        instance.put(key, value);
        key_time_instance.put(key,
                long.parselong(localdatetime.now().plusseconds(outsecond).format(yyyymmddhhmmss_fmt)));
        localcache.streaminstance();
    }

    /**
     * 
     * @param key
     * @param value
     * @return
     */
    @override
    public boolean putifabsent(string key, object value) {
        object result = null;
        result = instance.putifabsent(key, value);
        localcache.streaminstance();
        return result == null;
    }

    /**
     * 
     * @param key
     * @param value
     * @param outsecond 保存时间(秒)，超出时间，被清除
     * @return
     */
    @override
    public boolean putifabsent(string key, object value, int outtimesecond) {
        object result = null;
        result = instance.putifabsent(key, value);
        key_time_instance.putifabsent(key,
                long.parselong(localdatetime.now().plusseconds(outtimesecond).format(yyyymmddhhmmss_fmt)));
        localcache.streaminstance();
        return result == null;
    }

    /**
     * 获取缓存
     * 
     * @param key
     * @return
     */
    @suppresswarnings("unchecked")
    @override
    public <t> t get(string key) {
        t value = (t) instance.get(key);
        if (value == null) {
            return null;
        }
        if (localcache.istimeout(key)) {
            instance.remove(key);
            key_time_instance.remove(key);
            return null;
        } else {
            return value;
        }
    }

    @override
    public void expire(string key, int timeoutsecond) {
        key_time_instance.put(key,
                long.parselong(localdatetime.now().plusseconds(timeoutsecond).format(yyyymmddhhmmss_fmt)));
    }

    /**
     * 是否含有
     * 
     * @param key
     * @return
     */
    @override
    public boolean haskey(string key) {
        return instance.containskey(key);
    }

    /**
     * 删除
     * 
     * @param id
     * @return
     */
    @override
    public void remove(string key) {
        instance.remove(key);
    }

    /**
     * 删除并返回
     * 
     * @param id
     * @return
     */
    @suppresswarnings("unchecked")
    @override
    public <t> t removeandget(string key) {
        return (t) instance.remove(key);
    }

    /**
     * 整理缓存：<br>
     * 整理的缓存的线程只能一个，节约资源开销<br>
     * trim_interim<br>
     */
    private static void streaminstance() {

        if (tream_cache_flag.incrementandget() > 1) {
            return;
        }
        thread_pool.execute(() -> {
            long now = long.parselong(localdatetime.now().format(yyyymmddhhmmss_fmt));
            do {
                /*
                 * 1、超时缓存清除
                 */
                iterator<entry<string, object>> instanceit = instance.entryset().iterator();
                while (instanceit.hasnext()) {
                    string key = instanceit.next().getkey();
                    if (localcache.istimeout(key, now)) {
                        instanceit.remove();
                        key_time_instance.remove(key);
                    }
                }

                /*
                 * 2、 超容量,从首位开始清除
                 */
                if (instance.size() > maxcount) {
                    list<string> templist = new arraylist<>();
                    for (entry<string, object> en : instance.entryset()) {
                        templist.add(en.getkey());
                        if (instance.size() - templist.size() <= maxcount) {
                            templist.foreach(e -> {
                                instance.remove(e);
                                key_time_instance.remove(e);
                            });
                            break;
                        }
                    }
                }

                threadtool.sleep(trim_interim);
                now = long.valueof(localdatetime.now().format(yyyymmddhhmmss_fmt));
            } while (!instance.isempty());
            tream_cache_flag.set(0);
        });
    }

    /**
     * 判断key对比当前时间是否超时
     * 
     * @param key
     * @return
     */
    private static boolean istimeout(string key) {
        long now = long.parselong(localdatetime.now().format(yyyymmddhhmmss_fmt));
        return localcache.istimeout(key, now);
    }

    /**
     * 
     * 判断key对比now是否超时
     * 
     * @param key
     * @param now
     * @return
     */
    private static boolean istimeout(string key, long now) {
        long savetime = key_time_instance.get(key);
        return savetime == null || savetime < now;
    }
}