5

I'm on a webservice server and I have objects with an internal connection.
Initializing this connection takes really long so my idea was to use an object pool to reuse the connections among different requests.

The objects are connected to each user, so i prefer to use the username as key and the connection as value. But I don't want to have the connection open forever. Maybe after a while it should be destroyed if the user does not start requests any more.

I thought about using the apache object pool but i didn't see expiration there (correct me if i'm wrong)

The ehcache offers me notifications about eviction and expiration, but not triggered after the timeout was over, only if the cached object was touched again.

Does someone know a lib which can do this job for me?

4

3 回答 3

4

受 assylia 的想法的启发，我在这里使用了番石榴方式我的解决方案

final RemovalListener<Integer, Connection> removalListener = new RemovalListener<Integer, Connection>() {
    @Override
    public void onRemoval(final RemovalNotification<Integer, Connection> notification) {
        disconnect(notification.getValue());
    }
};

Cache<Integer, Connection> cache = CacheBuilder.newBuilder().maximumSize(20)
        .expireAfterAccess(30, TimeUnit.SECONDS)
        .removalListener(removalListener).build();
final ScheduledExecutorService cacheMaintanance = Executors.newSingleThreadScheduledExecutor();
cacheMaintanance.scheduleAtFixedRate(new Runnable() {
    @Override
    public void run() {
        cache.cleanUp();
    }
}, 10, 10, TimeUnit.SECONDS);
于 2013-07-16T14:44:55.723 回答
4

看看http://commons.apache.org/proper/commons-pool/api-1.6/org/apache/commons/pool/impl/GenericObjectPool.html

从javadoc：

Optionally, one may configure the pool to examine and possibly evict objects
as they sit idle in the pool and to ensure that a minimum number of idle
objects are available. This is performed by an "idle object eviction" thread,
which runs asynchronously. Caution should be used when configuring this
optional feature. Eviction runs contend with client threads for access to
objects in the pool, so if they run too frequently performance issues may
result.

.... 

minEvictableIdleTimeMillis specifies the minimum amount of time that 
an object may sit idle in the pool before it is eligible for eviction
due to idle time. When non-positive, no object will be dropped from 
the pool due to idle time alone. This setting has no effect unless
timeBetweenEvictionRunsMillis > 0. The default setting for this 
parameter is 30 minutes.

实现一个PoolableObjectFactory创建连接的方法，并实现PoolableObjectFactory.destroyObject(T object)关闭连接的方法。当对象被驱逐时，GenericObejctPool 将调用此方法。

于 2013-07-16T13:59:11.940 回答
0

最近添加了新的通用接口：

http://commons.apache.org/proper/commons-pool/

于 2014-07-08T19:46:59.610 回答