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[英]Apache ignite cache configuration about setStoreKeepBinary and setBackups
[英]How to get the configuration of a given cache in Apache Ignite?
例如,我按以下方式配置緩存:
public IgniteCache<String, Object> getOrCreateCache(String cacheName) {
Ignite ignite = Ignition.ignite();
CacheConfiguration<String, Object> cacheCfg = new CacheConfiguration<String, Object>(cacheName);
cacheCfg.setExpiryPolicyFactory(CreatedExpiryPolicy.factoryOf(new Duration(TimeUnit.SECONDS, 30)));
IgniteCache<String, Object> igniteCache = ignite.getOrCreateCache(cacheCfg);
return igniteCache;
}
現在如果以后我想從返回的igniteCache中找出到期策略的持續時間。 我可以用下面的hacky方式做到這一點,但它很難看,並且不是正確的方法:
import javax.cache.configuration.Factory;
import javax.cache.expiry.CreatedExpiryPolicy;
import javax.cache.expiry.Duration;
import org.apache.ignite.IgniteCache;
import org.apache.ignite.configuration.CacheConfiguration;
public class IgniteCacheManager {
private IgniteCache<String, Object> igniteCache;
public IgniteCacheManager(IgniteCache<String, Object> igniteCache) {
this.igniteCache = igniteCache;
}
public long getTimeToLive() {
long timeToLive = 0;
CacheConfiguration configuration = igniteCache.getConfiguration(CacheConfiguration.class);
Factory factory = configuration.getExpiryPolicyFactory();
Object obj = factory.create();
if (obj instanceof CreatedExpiryPolicy) {
CreatedExpiryPolicy cep = (CreatedExpiryPolicy)obj;
Duration dur = cep.getExpiryForCreation();
timeToLive = dur.getDurationAmount();
}
return timeToLive;
}
}
我正在研究的Apache Ignite版本是1.5.0.final
順便說一句,在Ehcache中,我可以通過以下方式獲得配置:
import net.sf.ehcache.Cache;
import net.sf.ehcache.config.CacheConfiguration;
public class EhcacheCacheManager {
private Cache cache;
public EhcacheCacheManager(Cache cache) {
this.cache = cache;
}
public long getTimeToLive() {
long timeToLive = 0;
CacheConfiguration config = cache.getCacheConfiguration();
timeToLive = config.getTimeToLiveSeconds();
return timeToLive;
}
}
目前我沒有看到任何其他方法來獲取公共API的緩存條目的TTL值。 但是,如果存在這樣的輔助方法,很可能它會以類似的方式實現,但只有一次為后續方法的調用返回相同的值時才會計算TTL。
因此,您只需通過計算一次TTL就可以簡單地改進代碼,它將變得更加優化。 此外,您可以隨時聯系Ignite社區,建議在公共API中添加類似的方法。
按照dmagda的建議(干杯),我聯系了Ignite社區。 正如Apache Ignite用戶論壇的AndreyVel所建議的那樣,目前我們可以在沒有黑客的情況下獲得ExpiryPolicy:
import javax.cache.configuration.Factory;
import javax.cache.expiry.ExpiryPolicy;
import org.apache.ignite.IgniteCache;
import org.apache.ignite.configuration.CacheConfiguration;
public class IgniteCacheManager {
private IgniteCache<String, Object> igniteCache;
public IgniteCacheManager(IgniteCache<String, Object> igniteCache) {
this.igniteCache = igniteCache;
}
public long getTimeToLive() {
CacheConfiguration configuration = igniteCache.getConfiguration(CacheConfiguration.class);
Factory factory = configuration.getExpiryPolicyFactory();
ExpiryPolicy policy = factory.create();
long timeToLive = policy.getExpiryForCreation().getDurationAmount();
return timeToLive;
}
}
來自論壇的alexey.goncharuk的評論,他同意這種方式有點尷尬,它只涵蓋配置的ExpiryPolicy,目前無法檢查是否使用withExpiryPolicy()方法創建了一個IgniteCache實例。
他認為可以在IgniteCache上添加getExpiryPolicy(),如果這是默認緩存實例,則返回已配置的到期策略(可能為null),如果使用withExpiryPolicy()創建緩存實例,則返回用戶指定的到期策略。
將此交叉發布到Ignite開發列表,以查看開發社區的想法。
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