DefaultFilterComponentBuilder creates builder attributes for onMatch/onMismatch without performing null checks. #3464
Description
Log4j 2.24.3
When using a configuration builder and adding a FilterComponentBuilder, generating XML from the ConfigurationBuilder causes exception when the filter is defined with a null OnMatch/OnMismatch Result.
Configuring the onMatch/onMismatch attributes is not required - null should be a valid value.
In this case, no attributtes should be added.
However in tthe DefaulttFilterComponentBuilder, attributes are added to tthe builder without performing a null-check first.
class DefaultFilterComponentBuilder extends DefaultComponentAndConfigurationBuilder<FilterComponentBuilder>
implements FilterComponentBuilder {
public DefaultFilterComponentBuilder(
final DefaultConfigurationBuilder<? extends Configuration> builder,
final String type,
final String onMatch,
final String onMismatch) {
super(builder, type);
addAttribute(AbstractFilterBuilder.ATTR_ON_MATCH, onMatch);
addAttribute(AbstractFilterBuilder.ATTR_ON_MISMATCH, onMismatch);
}
}
This results attributes with null values in the builder tree which can cause XML serialization problems.
I think this might be better:
class DefaultFilterComponentBuilder extends DefaultComponentAndConfigurationBuilder<FilterComponentBuilder>
implements FilterComponentBuilder {
public DefaultFilterComponentBuilder(
final DefaultConfigurationBuilder<? extends Configuration> builder,
final String type,
final String onMatch,
final String onMismatch) {
super(builder, type);
Optional.ofNullable(onMatch).ifPresent(() -> addAttribute(AbstractFilterBuilder.ATTR_ON_MATCH, onMatch));
Optional.ofNullable(onMismatch).ifPresent(() -> addAttribute(AbstractFilterBuilder.ATTR_ON_MISMATCH, onMismatch));
}
}