傳遞參數給Hazelcast MapStore

Question

我想寫我自己MapStore將訪問卡桑德拉。

我想能夠傳遞參數如卡桑德拉的地址，我怎麼能做到這一點，假設我可以使用構造函數。

我使用的是Dropwizard，特別是dropwizard-cassandra庫。

Answer 1

Hazelcast提供了將屬性（配置）從hazelcast.xml內部傳遞到MapStore實現的選項。不幸的是，你是對的，所以存在顯示瞭如何做到這一點的文檔沒有例子，但這裏的鏈接到XSD架構：https://github.com/hazelcast/hazelcast/blob/master/hazelcast/src/main/resources/hazelcast-config-3.7.xsd#L1731

對於文檔的例子，我傳遞信息到我們的文檔團隊添加一個:)

Answer 2

@danieln

@noctarius顯示，hazelcast.xml指定屬性的聲明方式。

但MapLoader沒有辦法將該屬性注入到實例中。

要做到這一點，您需要實現MapLoaderLifecycleSupport接口。 屬性將我注入init()方法

public interface MapLoaderLifecycleSupport { 
/** 
* Initializes this MapLoader implementation. Hazelcast will call 
* this method when the map is first used on the 
* HazelcastInstance. Implementation can 
* initialize required resources for the implementing 
* mapLoader, such as reading a config file and/or creating a 
* database connection. References to maps, other than the one on which 
* this {@code MapLoader} is configured, can be obtained from the 
* {@code hazelcastInstance} in this method's implementation. 
* <p> 
* On members joining a cluster, this method is executed during finalization 
* of the join operation, therefore care should be taken to adhere to the 
* rules for {@link com.hazelcast.spi.PostJoinAwareService#getPostJoinOperation()}. 
* If the implementation executes operations which may wait on locks or otherwise 
* block (e.g. waiting for network operations), this may result in a time-out and 
* obstruct the new member from joining the cluster. If blocking operations are 
* required for initialization of the {@code MapLoader}, consider deferring them 
* with a lazy initialization scheme. 
* </p> 
* 
* @param hazelcastInstance HazelcastInstance of this mapLoader. 
* @param properties  Properties set for this mapStore. see MapStoreConfig 
* @param mapName   name of the map. 
*/ 
void init(HazelcastInstance hazelcastInstance, Properties properties, String mapName); 

/** 
* Hazelcast will call this method before shutting down. 
* This method can be overridden to clean up the resources 
* held by this map loader implementation, such as closing the 
* database connections, etc. 
*/ 
void destroy(); 
} 

我們沒有卡桑德拉的例子，但我們確實有在您的處置蒙戈例如here。本實施例說明使屬性，以裝載機的方法。

此外，我們很樂意接受卡桑德拉的例子爲hazelcast-code-samples，如果您願意捐助一個。

如果您有任何問題，請在下面的評論中告訴我。

謝謝

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