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https://issues.apache.org/jira/browse/METRON-627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15754805#comment-15754805
]
ASF GitHub Bot commented on METRON-627:
---------------------------------------
Github user cestella commented on a diff in the pull request:
https://github.com/apache/incubator-metron/pull/397#discussion_r92836067
--- Diff:
metron-platform/metron-common/src/main/java/org/apache/metron/common/utils/ConversionUtils.java
---
@@ -18,23 +18,41 @@
package org.apache.metron.common.utils;
+import com.google.common.collect.Lists;
import org.apache.commons.beanutils.BeanUtilsBean2;
import org.apache.commons.beanutils.ConvertUtilsBean;
+import java.util.List;
+
public class ConversionUtils {
- private static ThreadLocal<ConvertUtilsBean> UTILS_BEAN = new
ThreadLocal<ConvertUtilsBean>() {
+ private static ThreadLocal<ConvertUtilsBean> UTILS_BEAN = new
ThreadLocal<ConvertUtilsBean>() {
@Override
protected ConvertUtilsBean initialValue() {
ConvertUtilsBean ret =
BeanUtilsBean2.getInstance().getConvertUtils();
ret.deregister();
- ret.register(false,true, 1);
+ ret.register(false, true, 1);
return ret;
}
};
+
public static <T> T convert(Object o, Class<T> clazz) {
- if(o == null) {
+ if (o == null) {
return null;
}
return clazz.cast(UTILS_BEAN.get().convert(o, clazz));
}
+
+ /**
+ * Performs naive List type conversion.
+ *
+ * @param from Source list
+ * @param clazz Class type to cast the List elements to
+ * @param <T> Source element type
+ * @param <U> Desired element type
+ * @return New List with the elements cast to the desired type
+ */
+ public static <T, U> List<U> convertList(List<T> from, Class<U> clazz) {
+ return Lists.transform(from, s -> clazz.cast(s));
--- End diff --
My issue with this is that above we are calling `convert` and is a coercive
operation (e.g. convert("1", Integer.class) == 1) rather than just a simple
cast. Can you make `convertList` call `convert` on the elements? If you
really want a naive version of this, feel free to make a `castList` method.
> Add HyperLogLogPlus implementation to Stellar
> ---------------------------------------------
>
> Key: METRON-627
> URL: https://issues.apache.org/jira/browse/METRON-627
> Project: Metron
> Issue Type: Improvement
> Reporter: Michael Miklavcic
>
> Calculating set cardinality can be a useful tool for a security analyst. For
> instance, a large volume of non-unique src ip addresses hitting your network
> may be an indication that you are currently under attack. There have been
> many advancements in distinct value (DV) estimation over the years. We have
> seen implementations evolve from K-Minimum-Values (KMV), to LogLog, to
> HyperLogLog, and now to Google's much-improved HyperLogLogPlu algorithm. The
> key improvements in this latest manifestation of the algorithm are:
> moves to a 64-bit hash
> handles sparse sets
> is more accurate with small cardinality
> This Jira tracks the effort to add a HyperLogLogPlus implementation to Metron.
> References:
> https://research.neustar.biz/2013/01/24/hyperloglog-googles-take-on-engineering-hll/
> http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/40671.pdf
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