复制代码 代码如下:
package com.happyelements.odin.util;

import static com.google.common.base.Preconditions.checkNotNull;

import org.jetbrains.annotations.NotNull;

import com.happyelements.odin.jedis.JedisClient;
import com.happyelements.rdcenter.commons.util.DateTimeUtil;

/**
* User: jude.wang
* Date: 14-1-16
* Time: 上午9:43
*/
public class ConcurrentUtil {

public static final String USER_LOCK_KEY_FORMAT = "user_lock_%d_%s";
public static final String CUSTOM_LOCK_FORMAT = "custom_lock_%s";
public static final JedisClient redisClient = JedisClient.getInstance();
public static final String UNLOCKED = "0";
public static final String LOCKED = "1";
private static final int MAX_REPEAT_TIMES = 10;

@NotNull
public static String buildUserLockKey(long userId, @NotNull String key) {
checkNotNull(key);
return String.format(USER_LOCK_KEY_FORMAT, userId, key);
}

@NotNull
public static String buildCustomLockKey(@NotNull String key) {
checkNotNull(key);
return String.format(CUSTOM_LOCK_FORMAT, key);
}

/**
* 此方法可以因为拿不到锁而导致operation没有执行
*
* @param key
* @see com.happyelements.odin.util.ConcurrentUtil#buildCustomLockKey(String)
* @see com.happyelements.odin.util.ConcurrentUtil#buildUserLockKey(long, String)
*
* @param operation
* @throws com.happyelements.odin.util.ConcurrentUtil.OperationNotExecException
* operation没有被执行
*/
public static void doJobWithLock(@NotNull String key, @NotNull ILockOperation operation) throws OperationNotExecException {

boolean locked = false;
try {
checkNotNull(key);
checkNotNull(operation);
locked = lock(key);

} catch (Throwable t) {
throw new OperationNotExecException(key, t);
}

try {
if (locked) {
// System.out.println(Thread.currentThread() + "\t" + "lock");
operation.doJob();
} else {
throw new OperationNotExecException(key);
}
} finally {
if (locked) {
unlock(key);
}
}
}

private static void unlock(String key) {
try {
checkNotNull(key);
String oldStatus = redisClient.getSet(key, UNLOCKED);
if (isUnlocked(oldStatus)) {
// lock->doJob->过期->unlock
// TODO LOG
}
} catch (Throwable t) {
// TODO LOG
}
// System.out.println(Thread.currentThread() + "\t" + "unlock");
}

private static boolean isUnlocked(String status) {
return status == null || status.equals(UNLOCKED);
}

private static boolean lock(String key) {

boolean locked = false;

for (int i = 0; i < MAX_REPEAT_TIMES; i++) {
String oldStatus = redisClient.getSet(key, LOCKED);

if (isUnlocked(oldStatus)) {
if (oldStatus == null) {
redisClient.expire(key, DateTimeUtil.MINUTE_SECOND * 5);
locked = true;
break;
}
locked = true;
break;
}
}

return locked;
}

public static interface ILockOperation {
void doJob();
}

/**
* {@link com.happyelements.odin.util.ConcurrentUtil.ILockOperation#doJob()}没有被执行
* 上层必须处理该异常，捕获到该异常可以retry本次操作，或者包装成{@link com.happyelements.rdcenter.commons.throwable.HeException} 抛出去
*/
public static class OperationNotExecException extends Exception {
public OperationNotExecException() {
}

public OperationNotExecException(String s) {
super(s);
}

public OperationNotExecException(String s, Throwable throwable) {
super(s, throwable);
}

public OperationNotExecException(Throwable throwable) {
super(throwable);
}
}
}