cassandra内部API应用三2010-07-07

cassandra内部API使用三2010-07-07
    /** 根据Key从缓存删除缓存数据.
     *
     * @param aKeyArea Key
     */
    public void remove(String aKeyArea)
    {
        CassandraClientPool pool = CassandraClientPoolFactory.INSTANCE.get();
        // 取得客户端（群集服务器）
        CassandraClient client = null;
        try
        {
            // 从群集服务器获得一个客户端
            client = pool.borrowClient(mCassandraClient);

            // Keyspace
            Keyspace keyspace =
                client.getKeyspace(mDefaultKeyspace);
            // ColumnPath
            ColumnPath columnPath = new ColumnPath(mDefaultColumnFamily);

            // 从缓存中清除
            keyspace.remove(aKeyArea, columnPath);

            // 为确保finally中能正确释放client，此处需重获取一次
            client = keyspace.getClient();
        }
        catch (Exception e)
        {
            sLog.error("根据Key从缓存删除缓存数据时出错。");
            sLog.error(e);
        }
        finally
        {
            // finally中释放client
            releaseClient(pool, client);
        }
    }

    /**根据Key和column从缓存删除缓存数据.
     * @param aKeyArea Key
     * @param aName column
     */
    public void remove(String aKeyArea, String aName)
    {
        CassandraClientPool pool = CassandraClientPoolFactory.INSTANCE.get();
        // 取得客户端（群集服务器）
        CassandraClient client = null;
        try
        {
            // 从群集服务器获得一个客户端
            client = pool.borrowClient(mCassandraClient);

            // Keyspace
            Keyspace keyspace =
                client.getKeyspace(mDefaultKeyspace);
            // ColumnPath
            ColumnPath columnPath = new ColumnPath(mDefaultColumnFamily);
            columnPath.setColumn(bytes(aName));

            // 从缓存中清除
            keyspace.remove(aKeyArea, columnPath);

            // 为确保finally中能正确释放client，此处需重获取一次
            client = keyspace.getClient();
        }
        catch (Exception e)
        {
            sLog.error("根据Key和column从缓存删除缓存数据时出错。");
            sLog.error(e);
        }
        finally
        {
            // finally中释放client
            releaseClient(pool, client);
        }
    }