[slf4j-dev] [JIRA] (SLF4J-371) Support the lambda expression in the Logger

[MiNG (JIRA)]

Title: Message Title

MiNG created an issue   SLF4J / SLF4J-371 Support the lambda _expression_ in the Logger Issue Type: Improvement Affects Versions: 1.7.22 Assignee: SLF4J developers list Components: Core API Created: 23/May/16 2:19 AM Priority: Major Reporter: MiNG 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: ``` if (LOGGER.isWarnEnabled()) { LOGGER.warn("some message: {}", Json.serialize(obj)); } ``` 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: ``` LOGGER.warn(formatter -> formatter.format("some message: {}", Json.serialize(obj))); ``` With the default method definition in the org.slf4j.Logger: ``` 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())); } } ...... } ``` Add Comment   This message was sent by Atlassian JIRA (v6.4.12#64027-sha1:e3691cc)

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