carterkozak commented on a change in pull request #555:
URL: https://github.com/apache/logging-log4j2/pull/555#discussion_r682086487
##########
File path:
log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/NameAbbreviator.java
##########
@@ -285,40 +285,40 @@ public PatternAbbreviatorFragment(
/**
* Abbreviate element of name.
*
- * @param buf buffer to receive element.
- * @param startPos starting index of name element.
- * @return starting index of next element.
+ * @param input input string which is being written to the output
{@code buf}.
+ * @param inputIndex starting index of name element in the {@code
input} string.
+ * @param buf buffer to receive element.
+ * @return starting index of next element.
*/
- public int abbreviate(final StringBuilder buf, final int startPos) {
- final int start = (startPos < 0) ? 0 : startPos;
- final int max = buf.length();
- int nextDot = -1;
- for (int i = start; i < max; i++) {
- if (buf.charAt(i) == '.') {
- nextDot = i;
- break;
- }
+ int abbreviate(final String input, final int inputIndex, final
StringBuilder buf) {
+ // ckozak: indexOf with a string is intentional. indexOf(String,
int) appears to
+ // have optimizations that don't apply to indexOf(char, int)
+ // which result in a >10% performance improvement in some
+ // NamePatternConverterBenchmark cases. This should be
re-evaluated with
+ // future java releases.
+ int nextDot = input.indexOf(".", inputIndex);
+ if (nextDot < 0) {
+ buf.append(input, inputIndex, input.length());
+ return nextDot;
}
- if (nextDot != -1) {
- if (nextDot - startPos > charCount) {
- buf.delete(startPos + charCount, nextDot);
Review comment:
This line as well as the `buf.insert` on 308 are potentially costly
because they shift the entire buffer beyond the deleted/inserted position.
Small buffers are relatively inexpensive because everything fits nicely in
cache, but larger values will have non-obvious performance problems.
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