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Question

我正在尝试返回包含在特定站点开始或结束的网络中的连接的集合。我无法弄清楚如何返回它并获取工作站参数。还有正确的方法在方法中创建hashMap，还是应该在它之外创建？

它给出了返回语句

的错误incompatible types: Connection cannot be converted to Collection<Connection>

CODE：

/**
 * Return a Collection containing all the Connections in the network that
 * start or end at a specified station
 *
 * @param station Station to/from which the Connection should run
 *
 * @return a Collection containing all the connections that start or end at
 * the specified station
 */

@Override
public Collection<Connection> getConnectionsFrom(Station station) {
    Map<Station, Connection> stationConnectionFrom = new HashMap<Station, Connection>();
    return stationConnectionFrom.get(station);
}

Answer 1

如果您无法更改方法签名，则可以执行以下操作：

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