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https://jira.qos.ch/browse/SLF4J-371?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=19656#comment-19656
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Dean Hiller commented on SLF4J-371:
-----------------------------------
@Federico ... I think perhaps I am not being clear. Sure slf4j-fluent just
like our wrapper works fine 'by itself'. If every 3rd party library also uses
slf4j-fluent(or any wrapper), there would also be know issue
However, say you have a 3rd party library that you bring in that uses slf4j,
and say your code uses the wrapper. The log statement by the 3rd party is 1
stack frame away while the wrapper is 2 stack frames away. This means, log
statements that use your wrapper can work fine while the 3rd party log
statements no longer work as it goes up the stack 2 times and finds the wrong
frame/file/line location.
I just went and tested this and sure enough...it does not work :(.(but I mean,
it should be obvious since slf4j uses the stack frames to get this info) In
webpieces development, it is my preference that I can click 'any' log statement
and it will take me to my code or 3rd party code correctly. unfortunately, we
have to back out of all wrappers including slf4j-fluent.
later,
Dean
> Support the lambda expression in the Logger
> -------------------------------------------
>
> Key: SLF4J-371
> URL: https://jira.qos.ch/browse/SLF4J-371
> Project: SLF4J
> Issue Type: Improvement
> Components: Core API
> Affects Versions: 1.7.22
> Reporter: MiNG
> Assignee: SLF4J developers list
> Fix For: 2.0
>
>
> In some cases, we don't want to calculate the expression for logging eagerly
> cause the performance reason. Then, we would write the code like the
> following:
> {code:java}
> if (LOGGER.isWarnEnabled())
> {
> LOGGER.warn("some message: {}", Json.serialize(obj));
> }{code}
> Before JDK8, there is no way to encapsulate the above code, because the
> expression is always calculated before passed as an argument. So, many "if"s
> appear in the code and smell badly.
> Now, the lambda expression is supported by JDK8, the above could be
> simplified like following:
> {code:java}
> LOGGER.warn(formatter -> formatter.format("some message: {}",
> Json.serialize(obj)));{code}
> With the default method definition in the org.slf4j.Logger:
> {code:java}
> public interface Logger
> {
> default void warn(Function<MessageFormatter, String> messageSupplier)
> {
> if (this.isWarnEnabled())
> {
> /* Calculate the expression only if the WARN level logging is enabled. */
> this.warn(messageSupplier.apply(this.getFormatter()));
> }
> }
> }{code}
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