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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.core.util.datetime;
import java.util.Calendar;
import java.util.Objects;
/**
* Custom time formatter that trades flexibility for performance. This formatter only supports the date patterns defined
* in {@link FixedFormat}. For any other date patterns use {@link FastDateFormat}.
*
* Related benchmarks: /log4j-perf/src/main/java/org/apache/logging/log4j/perf/jmh/TimeFormatBenchmark.java and
* /log4j-perf/src/main/java/org/apache/logging/log4j/perf/jmh/ThreadsafeDateFormatBenchmark.java
*/
public class FixedDateFormat {
/**
* Enumeration over the supported date/time format patterns.
*
* Package protected for unit tests.
*/
public enum FixedFormat {
/**
* ABSOLUTE time format: {@code "HH:mm:ss,SSS"}.
*/
ABSOLUTE("HH:mm:ss,SSS", null, 0, ':', 1, ',', 1),
/**
* ABSOLUTE time format variation with period separator: {@code "HH:mm:ss.SSS"}.
*/
ABSOLUTE_PERIOD("HH:mm:ss.SSS", null, 0, ':', 1, '.', 1),
/**
* COMPACT time format: {@code "yyyyMMddHHmmssSSS"}.
*/
COMPACT("yyyyMMddHHmmssSSS", "yyyyMMdd", 0, ' ', 0, ' ', 0),
/**
* DATE_AND_TIME time format: {@code "dd MMM yyyy HH:mm:ss,SSS"}.
*/
DATE("dd MMM yyyy HH:mm:ss,SSS", "dd MMM yyyy ", 0, ':', 1, ',', 1),
/**
* DATE_AND_TIME time format variation with period separator: {@code "dd MMM yyyy HH:mm:ss.SSS"}.
*/
DATE_PERIOD("dd MMM yyyy HH:mm:ss.SSS", "dd MMM yyyy ", 0, ':', 1, '.', 1),
/**
* DEFAULT time format: {@code "yyyy-MM-dd HH:mm:ss,SSS"}.
*/
DEFAULT("yyyy-MM-dd HH:mm:ss,SSS", "yyyy-MM-dd ", 0, ':', 1, ',', 1),
/**
* DEFAULT time format variation with period separator: {@code "yyyy-MM-dd HH:mm:ss.SSS"}.
*/
DEFAULT_PERIOD("yyyy-MM-dd HH:mm:ss.SSS", "yyyy-MM-dd ", 0, ':', 1, '.', 1),
/**
* ISO8601_BASIC time format: {@code "yyyyMMdd'T'HHmmss,SSS"}.
*/
ISO8601_BASIC("yyyyMMdd'T'HHmmss,SSS", "yyyyMMdd'T'", 2, ' ', 0, ',', 1),
/**
* ISO8601 time format: {@code "yyyy-MM-dd'T'HH:mm:ss,SSS"}.
*/
ISO8601("yyyy-MM-dd'T'HH:mm:ss,SSS", "yyyy-MM-dd'T'", 2, ':', 1, ',', 1);
private final String pattern;
private final String datePattern;
private final int escapeCount;
private final char timeSeparatorChar;
private final int timeSeparatorLength;
private final char millisSeparatorChar;
private final int millisSeparatorLength;
FixedFormat(final String pattern, final String datePattern, final int escapeCount, final char timeSeparator,
final int timeSepLength, final char millisSeparator, final int millisSepLength) {
this.timeSeparatorChar = timeSeparator;
this.timeSeparatorLength = timeSepLength;
this.millisSeparatorChar = millisSeparator;
this.millisSeparatorLength = millisSepLength;
this.pattern = Objects.requireNonNull(pattern);
this.datePattern = datePattern; // may be null
this.escapeCount = escapeCount;
}
/**
* Returns the full pattern.
*
* @return the full pattern
*/
public String getPattern() {
return pattern;
}
/**
* Returns the date part of the pattern.
*
* @return the date part of the pattern
*/
public String getDatePattern() {
return datePattern;
}
/**
* Returns the FixedFormat with the name or pattern matching the specified string or {@code null} if not found.
*
* @param nameOrPattern the name or pattern to find a FixedFormat for
* @return the FixedFormat with the name or pattern matching the specified string
*/
public static FixedFormat lookup(final String nameOrPattern) {
for (final FixedFormat type : FixedFormat.values()) {
if (type.name().equals(nameOrPattern) || type.getPattern().equals(nameOrPattern)) {
return type;
}
}
return null;
}
/**
* Returns the length of the resulting formatted date and time strings.
*
* @return the length of the resulting formatted date and time strings
*/
public int getLength() {
return pattern.length() - escapeCount;
}
/**
* Returns the length of the date part of the resulting formatted string.
*
* @return the length of the date part of the resulting formatted string
*/
public int getDatePatternLength() {
return getDatePattern() == null ? 0 : getDatePattern().length() - escapeCount;
}
/**
* Returns the {@code FastDateFormat} object for formatting the date part of the pattern or {@code null} if the
* pattern does not have a date part.
*
* @return the {@code FastDateFormat} object for formatting the date part of the pattern or {@code null}
*/
public FastDateFormat getFastDateFormat() {
return getDatePattern() == null ? null : FastDateFormat.getInstance(getDatePattern());
}
}
private final FixedFormat fixedFormat;
private final int length;
private final FastDateFormat fastDateFormat; // may be null
private final char timeSeparatorChar;
private final char millisSeparatorChar;
private final int timeSeparatorLength;
private final int millisSeparatorLength;
private volatile long midnightToday = 0;
private volatile long midnightTomorrow = 0;
// cachedDate does not need to be volatile because
// there is a write to a volatile field *after* cachedDate is modified,
// and there is a read from a volatile field *before* cachedDate is read.
// The Java memory model guarantees that because of the above,
// changes to cachedDate in one thread are visible to other threads.
// See http://g.oswego.edu/dl/jmm/cookbook.html
private char[] cachedDate; // may be null
private int dateLength;
/**
* Constructs a FixedDateFormat for the specified fixed format.
*
* Package protected for unit tests.
*
* @param fixedFormat the fixed format
*/
FixedDateFormat(final FixedFormat fixedFormat) {
this.fixedFormat = Objects.requireNonNull(fixedFormat);
this.timeSeparatorChar = fixedFormat.timeSeparatorChar;
this.timeSeparatorLength = fixedFormat.timeSeparatorLength;
this.millisSeparatorChar = fixedFormat.millisSeparatorChar;
this.millisSeparatorLength = fixedFormat.millisSeparatorLength;
this.length = fixedFormat.getLength();
this.fastDateFormat = fixedFormat.getFastDateFormat();
}
public static FixedDateFormat createIfSupported(final String... options) {
if (options == null || options.length == 0 || options[0] == null) {
return new FixedDateFormat(FixedFormat.DEFAULT);
}
if (options.length > 1) {
return null; // time zone not supported
}
final FixedFormat type = FixedFormat.lookup(options[0]);
return type == null ? null : new FixedDateFormat(type);
}
/**
* Returns a new {@code FixedDateFormat} object for the specified {@code FixedFormat} and a {@code null} TimeZone.
*
* @param format the format to use
* @return a new {@code FixedDateFormat} object
*/
public static FixedDateFormat create(final FixedFormat format) {
return new FixedDateFormat(format);
}
/**
* Returns the full pattern of the selected fixed format.
*
* @return the full date-time pattern
*/
public String getFormat() {
return fixedFormat.getPattern();
}
// Profiling showed this method is important to log4j performance. Modify with care!
// 30 bytes (allows immediate JVM inlining: <= -XX:MaxInlineSize=35 bytes)
private long millisSinceMidnight(final long now) {
if (now >= midnightTomorrow || now < midnightToday) {
updateMidnightMillis(now);
}
return now - midnightToday;
}
private void updateMidnightMillis(final long now) {
updateCachedDate(now);
midnightToday = calcMidnightMillis(now, 0);
midnightTomorrow = calcMidnightMillis(now, 1);
}
static long calcMidnightMillis(final long time, final int addDays) {
final Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(time);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
cal.add(Calendar.DATE, addDays);
return cal.getTimeInMillis();
}
private void updateCachedDate(final long now) {
if (fastDateFormat != null) {
final StringBuilder result = fastDateFormat.format(now, new StringBuilder());
cachedDate = result.toString().toCharArray();
dateLength = result.length();
}
}
// Profiling showed this method is important to log4j performance. Modify with care!
// 28 bytes (allows immediate JVM inlining: <= -XX:MaxInlineSize=35 bytes)
public String format(final long time) {
final char[] result = new char[length << 1]; // double size for locales with lengthy DateFormatSymbols
final int written = format(time, result, 0);
return new String(result, 0, written);
}
// Profiling showed this method is important to log4j performance. Modify with care!
// 31 bytes (allows immediate JVM inlining: <= -XX:MaxInlineSize=35 bytes)
public int format(final long time, final char[] buffer, final int startPos) {
// Calculate values by getting the ms values first and do then
// calculate the hour minute and second values divisions.
// Get daytime in ms: this does fit into an int
// int ms = (int) (time % 86400000);
final int ms = (int) (millisSinceMidnight(time));
writeDate(buffer, startPos);
return writeTime(ms, buffer, startPos + dateLength) - startPos;
}
// Profiling showed this method is important to log4j performance. Modify with care!
// 22 bytes (allows immediate JVM inlining: <= -XX:MaxInlineSize=35 bytes)
private void writeDate(final char[] buffer, final int startPos) {
if (cachedDate != null) {
System.arraycopy(cachedDate, 0, buffer, startPos, dateLength);
}
}
// Profiling showed this method is important to log4j performance. Modify with care!
// 262 bytes (will be inlined when hot enough: <= -XX:FreqInlineSize=325 bytes on Linux)
private int writeTime(int ms, final char[] buffer, int pos) {
final int hours = ms / 3600000;
ms -= 3600000 * hours;
final int minutes = ms / 60000;
ms -= 60000 * minutes;
final int seconds = ms / 1000;
ms -= 1000 * seconds;
// Hour
int temp = hours / 10;
buffer[pos++] = ((char) (temp + '0'));
// Do subtract to get remainder instead of doing % 10
buffer[pos++] = ((char) (hours - 10 * temp + '0'));
buffer[pos] = timeSeparatorChar;
pos += timeSeparatorLength;
// Minute
temp = minutes / 10;
buffer[pos++] = ((char) (temp + '0'));
// Do subtract to get remainder instead of doing % 10
buffer[pos++] = ((char) (minutes - 10 * temp + '0'));
buffer[pos] = timeSeparatorChar;
pos += timeSeparatorLength;
// Second
temp = seconds / 10;
buffer[pos++] = ((char) (temp + '0'));
buffer[pos++] = ((char) (seconds - 10 * temp + '0'));
buffer[pos] = millisSeparatorChar;
pos += millisSeparatorLength;
// Millisecond
temp = ms / 100;
buffer[pos++] = ((char) (temp + '0'));
ms -= 100 * temp;
temp = ms / 10;
buffer[pos++] = ((char) (temp + '0'));
ms -= 10 * temp;
buffer[pos++] = ((char) (ms + '0'));
return pos;
}
}