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https://issues.apache.org/jira/browse/METRON-830?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15960040#comment-15960040
]
ASF GitHub Bot commented on METRON-830:
---------------------------------------
Github user mattf-horton commented on a diff in the pull request:
https://github.com/apache/incubator-metron/pull/516#discussion_r110291091
--- Diff:
metron-platform/metron-common/src/main/java/org/apache/metron/common/dsl/functions/StringFunctions.java
---
@@ -343,4 +343,89 @@ public Object apply(List<Object> args) {
return String.format(format, formatArgs);
}
}
+
+ @Stellar( name="CHOP"
+ , description = "Remove the last character from a String"
+ , params = { "the String to chop last character from, may be
null"}
+ , returns = "String without last character, null if null String
input"
+ )
+ public static class chop extends BaseStellarFunction {
+
+ @Override
+ public Object apply(List<Object> strings) {
+
+ if(strings.size() == 0) {
+ throw new IllegalArgumentException("[CHOP] missing argument:
string to be chopped");
+ }
+
+ String chop = StringUtils.chop((String) strings.get(0));
+ return chop;
+ }
+ }
+
+ @Stellar( name = "PREPENDIFMISSING"
+ , description = "Prepends the prefix to the start of the string
if the string does not already start with any of the prefixes"
+ , params = { "str - The string.", "prefix - The prefix to
prepend to the start of the string", "prefixes - Additional prefixes that are
valid" }
+ , returns = "A new String if prefix was prepended, the same
string otherwise."
+ )
+ public static class prependifmissing extends BaseStellarFunction {
+
+ @Override
+ public Object apply(List<Object> strings) {
+
+ String prefixed;
+ switch (strings.size()) {
+ case 2: prefixed =
org.apache.commons.lang3.StringUtils.prependIfMissing((String) strings.get(0),
(String) strings.get(1));
+ break;
+ case 3: prefixed =
org.apache.commons.lang3.StringUtils.prependIfMissing((String) strings.get(0),
(String) strings.get(1), (String) strings.get(2));
+ break;
+ default: throw new IllegalArgumentException("[PREPENDIFMISSING]
incorrect arguments. Usage: PREPENDIFMISSING <String> <prefix> [<prefix>...]");
--- End diff --
@cestella , isn't there boilerplate in the Stellar executor that
automagically dumps the @Stellar declaration on any error? So one doesn't have
to implement `Usage:` in the operator?
@anandsubbu , but you can still provide useful contextual info, like what
arguments were actually provided, or in this case, at least how many (incorrect
number) of arguments were provided.
The issues raised in PREPENDIFMISSING also apply to APPENDIFMISSING, of
course.
> Adding StringFunctions to Stellar - chop, prependifmissing, appendifmissing
> and countmatches
> --------------------------------------------------------------------------------------------
>
> Key: METRON-830
> URL: https://issues.apache.org/jira/browse/METRON-830
> Project: Metron
> Issue Type: Bug
> Affects Versions: 0.3.1
> Reporter: Anand Subramanian
> Assignee: Anand Subramanian
> Fix For: Next + 1
>
>
> Enhance Stellar by adding the following apache common string functions.
> - chop -> Remove the last character from a String.
> - prependifmissing -> Prepends the prefix to the start of the string if the
> string does not already start with any of the prefixes.
> - appendifmissing -> Appends the suffix to the end of the string if the
> string does not already end with any of the suffixes.
> - countmatches -> Counts how many times the substring appears in the larger
> string.
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