PengZheng commented on code in PR #721:
URL: https://github.com/apache/celix/pull/721#discussion_r1466403043
##########
libs/utils/include/celix_filter.h:
##########
@@ -54,15 +55,53 @@
* Apache Celix filters can be used to match a set of Apache Celix properties
and such Apache Celix filters should be
* used together with a set of properties.
*
- * Internally attribute values will be parsed to a long, double, boolean and
Apache Celix version if
- * possible during creation. And these typed attribute values will be used in
the to-be-matched property value,
- * if the property value is of the same type.
+ * #Filter matching and property value types
+ * When matching a filter the attribute type of a filter node is used to
determine the type of the property value and
+ * this type is used to compare the property value with the filter attribute
value.
+ * If the property value is of a type that the filter attribute value can be
parsed to, the filter attribute value the
+ * comparison is done with the matching type. If the property value is not of
a type that the filter attribute value
+ * can be parsed to, the comparison is done with the string representation of
the property value.
*
+ * Internally attribute values will be parsed to a long, double, boolean,
Apache Celix version and array list of
+ * longs, doubles, booleans, Apache Celix versions and string if possible
during creation.
+ * And these typed attribute values will be used in the to-be-matched property
value.
+ *
+ * Example: The filter "(key>20)" and a property set with a long value 3 for
key "key", will match and the same
+ * filter but with a property set which has a string value "3" for key "key",
will not match.
Review Comment:
If the above understanding is correct (it could be wrong), then for string
value "3", the filter operation `>` should be string comparison.
##########
libs/utils/include/celix_filter.h:
##########
@@ -54,15 +55,53 @@
* Apache Celix filters can be used to match a set of Apache Celix properties
and such Apache Celix filters should be
* used together with a set of properties.
*
- * Internally attribute values will be parsed to a long, double, boolean and
Apache Celix version if
- * possible during creation. And these typed attribute values will be used in
the to-be-matched property value,
- * if the property value is of the same type.
+ * #Filter matching and property value types
+ * When matching a filter the attribute type of a filter node is used to
determine the type of the property value and
+ * this type is used to compare the property value with the filter attribute
value.
+ * If the property value is of a type that the filter attribute value can be
parsed to, the filter attribute value the
+ * comparison is done with the matching type. If the property value is not of
a type that the filter attribute value
+ * can be parsed to, the comparison is done with the string representation of
the property value.
Review Comment:
I found this paragraph quite confusing. A filter is created from a string,
which carries no type information. On the other hand, JAVA properties (or
recent version of Celix properties) does carry type information. How to use the
attribute type of a filter node, which is absent in the string representation
of LDAP filter, to determine the type of the property value?
Each well-known property like "CELIX_FRAMEWORK_SERVICE_ID" has well-defined
type. The basic assumption is that each well-known property is set to its
well-defined type. When matching a properties against a LDAP filter, we should
assume the type information carried in properties is correct, and use that to
determine the attribute type of a filter node.
"If the property value is not of a type that the filter attribute value can
be parsed to", the matching should simply failed, because we assume the type
information in properties is always correct.
I may need to find some time to check OSGi Java implementation like Felix.
##########
libs/utils/include/celix_filter.h:
##########
@@ -54,15 +55,53 @@
* Apache Celix filters can be used to match a set of Apache Celix properties
and such Apache Celix filters should be
* used together with a set of properties.
*
- * Internally attribute values will be parsed to a long, double, boolean and
Apache Celix version if
- * possible during creation. And these typed attribute values will be used in
the to-be-matched property value,
- * if the property value is of the same type.
+ * #Filter matching and property value types
+ * When matching a filter the attribute type of a filter node is used to
determine the type of the property value and
+ * this type is used to compare the property value with the filter attribute
value.
+ * If the property value is of a type that the filter attribute value can be
parsed to, the filter attribute value the
+ * comparison is done with the matching type. If the property value is not of
a type that the filter attribute value
+ * can be parsed to, the comparison is done with the string representation of
the property value.
*
+ * Internally attribute values will be parsed to a long, double, boolean,
Apache Celix version and array list of
+ * longs, doubles, booleans, Apache Celix versions and string if possible
during creation.
+ * And these typed attribute values will be used in the to-be-matched property
value.
+ *
+ * Example: The filter "(key>20)" and a property set with a long value 3 for
key "key", will match and the same
Review Comment:
(key, 3) can not match `(key>20)`, since `3 < 20`.
##########
libs/utils/include/celix_filter.h:
##########
@@ -54,15 +55,53 @@
* Apache Celix filters can be used to match a set of Apache Celix properties
and such Apache Celix filters should be
* used together with a set of properties.
*
- * Internally attribute values will be parsed to a long, double, boolean and
Apache Celix version if
- * possible during creation. And these typed attribute values will be used in
the to-be-matched property value,
- * if the property value is of the same type.
+ * #Filter matching and property value types
+ * When matching a filter the attribute type of a filter node is used to
determine the type of the property value and
+ * this type is used to compare the property value with the filter attribute
value.
+ * If the property value is of a type that the filter attribute value can be
parsed to, the filter attribute value the
+ * comparison is done with the matching type. If the property value is not of
a type that the filter attribute value
+ * can be parsed to, the comparison is done with the string representation of
the property value.
*
+ * Internally attribute values will be parsed to a long, double, boolean,
Apache Celix version and array list of
+ * longs, doubles, booleans, Apache Celix versions and string if possible
during creation.
+ * And these typed attribute values will be used in the to-be-matched property
value.
+ *
+ * Example: The filter "(key>20)" and a property set with a long value 3 for
key "key", will match and the same
+ * filter but with a property set which has a string value "3" for key "key",
will not match.
+ *
+ * #Filter matching and property value arrays
+ * If a filter matches a property set entry which has an array value (either a
long, boolean, double, string or version
+ * array) the filter match will check if the array contains a single entry
which matches the filter attribute value using
+ * the aforementioned "Filter matching and property value types" rules.
+ *
+ * Filter matching with array is supported for the following operands: "="
(including substring), ">=", "<=", ">", "<"
+ * and "~=".
+ *
+ * Example: The filter "(key=3)" will match the property set entry with key
"key" and a long array list value of
+ * [1,2,3].
+ *
+ * #Substring filter operand
+ * The substring filter operand is used to match a string value with a filter
attribute value. The filter attribute
+ * value can contain a `*` to match any character sequence. The filter
attribute value can also contain a `*` at the
+ * start or end of the string to match any character sequence at the start or
end of the string.
+ *
+ * A substring filter operand uses the string representation of the property
value to match with the filter attribute
+ * or if the property value is an string array the substring filter operand
will match if any of the string array values.
+ *
+ * Example: The filter "(key=*Smith)" will match the property set entry with
key "key" and a string value "John Smith".
+ *
+ * #Approx filter operand
+ * The approx filter operand is used to check if the filter attribute value is
a substring of the property value.
+ * A approx filter operand uses the string representation of the property
value to match with the filter attribute or
+ * if the property value is an string array the approx filter operand will
match if any of the string array values.
Review Comment:
The OSGi spec says "the evaluation of the approximate match ('~=') filter
type is implementation specific but should at least ignore case and white space
differences. Codes such as Soundex or other smart closeness comparisons could
be used. " I didn't expect it to be a substring.
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