Gflog

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())

Source: epam/gflog — distributed by TomeVault.