org.glowroot.agent.plugin.logger.LoggerNameAbbreviator Maven / Gradle / Ivy
/**
* Logback: the reliable, generic, fast and flexible logging framework.
* Copyright (C) 1999-2015, QOS.ch. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation.
*/
package org.glowroot.agent.plugin.logger;
// copied form ch.qos.logback.classic.pattern.TargetLengthBasedClassNameAbbreviator
class LoggerNameAbbreviator {
private static final int MAX_DOTS = 16;
private final int targetLength;
LoggerNameAbbreviator(int targetLength) {
this.targetLength = targetLength;
}
String abbreviate(String fqClassName) {
StringBuilder buf = new StringBuilder(targetLength);
if (fqClassName == null) {
throw new IllegalArgumentException("Class name may not be null");
}
int inLen = fqClassName.length();
if (inLen < targetLength) {
return fqClassName;
}
int[] dotIndexesArray = new int[MAX_DOTS];
int[] lengthArray = new int[MAX_DOTS + 1];
int dotCount = computeDotIndexes(fqClassName, dotIndexesArray);
// if there are not dots than abbreviation is not possible
if (dotCount == 0) {
return fqClassName;
}
computeLengthArray(fqClassName, dotIndexesArray, lengthArray, dotCount);
for (int i = 0; i <= dotCount; i++) {
if (i == 0) {
buf.append(fqClassName.substring(0, lengthArray[i] - 1));
} else {
buf.append(fqClassName.substring(dotIndexesArray[i - 1],
dotIndexesArray[i - 1] + lengthArray[i]));
}
}
return buf.toString();
}
private void computeLengthArray(final String className, int[] dotArray, int[] lengthArray,
int dotCount) {
int toTrim = className.length() - targetLength;
int len;
for (int i = 0; i < dotCount; i++) {
int previousDotPosition = -1;
if (i > 0) {
previousDotPosition = dotArray[i - 1];
}
int available = dotArray[i] - previousDotPosition - 1;
len = (available < 1) ? available : 1;
if (toTrim > 0) {
len = (available < 1) ? available : 1;
} else {
len = available;
}
toTrim -= (available - len);
lengthArray[i] = len + 1;
}
int lastDotIndex = dotCount - 1;
lengthArray[dotCount] = className.length() - dotArray[lastDotIndex];
}
private static int computeDotIndexes(final String className, int[] dotArray) {
int dotCount = 0;
int k = 0;
while (true) {
// ignore the $ separator in our computations. This is both convenient
// and sensible.
k = className.indexOf('.', k);
if (k != -1 && dotCount < MAX_DOTS) {
dotArray[dotCount] = k;
dotCount++;
k++;
} else {
break;
}
}
return dotCount;
}
}