private void serializeAdditionalFieldsAndMDC()

in log4j2-ecs-layout/src/main/java/co/elastic/logging/log4j2/EcsLayout.java [164:198]
34 lines of code
9 McCabe index (conditional complexity)

    private void serializeAdditionalFieldsAndMDC(LogEvent event, StringBuilder builder) {
        final int length = additionalFields.length;
        if (length > 0) {
            final StrSubstitutor strSubstitutor = getConfiguration().getStrSubstitutor();
            for (int i = 0; i < length; i++) {
                KeyValuePair additionalField = additionalFields[i];
                PatternFormatter[] formatters = fieldValuePatternFormatter[i];
                CharSequence value = null;
                if (formatters != null) {
                    StringBuilder buffer = EcsJsonSerializer.getMessageStringBuilder();
                    formatPattern(event, formatters, buffer);
                    if (buffer.length() > 0) {
                        value = buffer;
                    }
                } else if (valueNeedsLookup(additionalField.getValue()) && !FORMAT_MESSAGES_PATTERN_DISABLE_LOOKUPS) {
                    StringBuilder lookupValue = EcsJsonSerializer.getMessageStringBuilder();
                    lookupValue.append(additionalField.getValue());
                    if (strSubstitutor.replaceIn(event, lookupValue)) {
                        value = lookupValue;
                    }
                } else {
                    value = additionalField.getValue();
                }

                if (value != null) {
                    builder.append('\"');
                    JsonUtils.quoteAsString(additionalField.getKey(), builder);
                    builder.append("\":\"");
                    JsonUtils.quoteAsString(EcsJsonSerializer.toNullSafeString(value), builder);
                    builder.append("\",");
                }
            }
        }
        mdcSerializer.serializeMdc(event, builder);
    }