gflog

name	gflog
description	Add or update logging statements using GFLog library. Use when creating new log statements, refactoring existing logging code (JUL/SLF4J), or when you see string concatenation in log statements.
context	fork

GFLog logging

Add logging statements using our company standard GFLog library.

Process

1. Identify logging statements that need creation or conversion
2. Replace string concatenation with a-la printf-style formatting (with only %s available for all types)
3. Apply appropriate formatter methods (withTimestamp, withDecimal64, etc.)
4. Add guard conditions for expensive operations
5. Verify log level consistency

Guidelines

• When you see string concatenation in existing log statement you need to replace it with printf-like approach followed by GFLog.

  For example:

  LOGGER.log(Level.FINE, "Found " + list.size() + " instruments");

  should be

  LOG.debug("Found %s instruments").with(list.size());

Formatters by Data Type

Timestamps (epoch millis as long):

• Use: .withTimestamp(value)
• Example: .withTimestamp(System.currentTimeMillis())

DFP-encoded money/quantities (long representing Decimal64):

• Use: .withDecimal64(value)
• Example: .withDecimal64(price) for prices, .withDecimal64(quantity) for quantities

Alphanumeric identifiers (@Alphanumeric long):

• Use: .withAlphanumeric(value)
• Example: .withAlphanumeric(instrumentId) for encoded symbol/ID

Regular values:

• Use: .with(value)

Quick Start

Initialize logger (at class level):

protected static final Log LOG = LogFactory.getLog(CurrentClass.class);

Basic logging:

LOG.info("Hello %s! Current time is %s")
   .with(name)
   .withTimestamp(System.currentTimeMillis());

With guard for expensive operations:

if (LOG.isDebugEnabled()) {
    LOG.debug("Computed result: %s").with(expensiveComputation());
}

Here we need to make sure that function expensiveComputation() does not perform any logging of its own inside its body. GFLog is not re-entrant. In such cases it is better to move function call outside of logging statement:

if (LOG.isDebugEnabled()) {
    var x = expensiveComputation();
    LOG.debug("Computed result: %s").with(x);
}

Typical pitfalls

• Only %s is supported as a format specifier — type-specific specifiers (%d, %04d, %f, etc.) are not recognized.

  • Incorrect: LOG.info("Value is %04d").with(value)
  • Correct: LOG.info("Value is %s").with(value)

• Every .with*() call must have a matching %s placeholder in the format string.

  • Incorrect: LOG.error("Error").with(exception)
  • Correct: LOG.error("Error: %s").with(exception)

• Use typed appenders instead of .with() for timestamps and DFP values:

  • Epoch millis → .withTimestamp(value), epoch nanos → .withTimestampNs(value)
  • Decimal64-encoded long → .withDecimal64(value)
  • Incorrect: LOG.info("Message time is %s").with(message.getTimestamp())
  • Correct: LOG.info("Message time is %s").withTimestamp(message.getTimestamp())