Java tutorial
/* * Copyright (C) 2011 FasterXML, LLC * * Licensed 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 com.segment.analytics.gson; import com.google.gson.JsonParseException; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.Locale; import java.util.TimeZone; /** * Moshi's date formatter, pruned to Segment's needs. Forked from this file: * https://github.com/square/moshi/blob/master/adapters/src/main/java/com/squareup/moshi/Iso8601Utils.java * * ------------------------------------------------------------------------------------------------- * * Jacksons date formatter, pruned to Moshi's needs. Forked from this file: * https://github.com/FasterXML/jackson-databind/blob/master/src/main/java/com/fasterxml/jackson/databind/util/ISO8601Utils.java * * Utilities methods for manipulating dates in iso8601 format. This is much much faster and GC * friendly than using SimpleDateFormat so highly suitable if you (un)serialize lots of date * objects. * * Supported parse format: [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh[:]mm]] * * @see <a href="http://www.w3.org/TR/NOTE-datetime">this specification</a> */ final class Iso8601Utils { /** ID to represent the 'GMT' string */ static final String GMT_ID = "GMT"; /** The GMT timezone, prefetched to avoid more lookups. */ static final TimeZone TIMEZONE_Z = TimeZone.getTimeZone(GMT_ID); /** Returns {@code date} formatted as yyyy-MM-ddThh:mm:ss.sssZ */ static String format(Date date) { Calendar calendar = new GregorianCalendar(TIMEZONE_Z, Locale.US); calendar.setTime(date); // estimate capacity of buffer as close as we can (yeah, that's pedantic ;) int capacity = "yyyy-MM-ddThh:mm:ss.sssZ".length(); StringBuilder formatted = new StringBuilder(capacity); padInt(formatted, calendar.get(Calendar.YEAR), "yyyy".length()); formatted.append('-'); padInt(formatted, calendar.get(Calendar.MONTH) + 1, "MM".length()); formatted.append('-'); padInt(formatted, calendar.get(Calendar.DAY_OF_MONTH), "dd".length()); formatted.append('T'); padInt(formatted, calendar.get(Calendar.HOUR_OF_DAY), "hh".length()); formatted.append(':'); padInt(formatted, calendar.get(Calendar.MINUTE), "mm".length()); formatted.append(':'); padInt(formatted, calendar.get(Calendar.SECOND), "ss".length()); formatted.append('.'); padInt(formatted, calendar.get(Calendar.MILLISECOND), "sss".length()); formatted.append('Z'); return formatted.toString(); } /** * Parse a date from ISO-8601 formatted string. It expects a format * [yyyy-MM-dd|yyyyMMdd][T(hh:mm[:ss[.sss]]|hhmm[ss[.sss]])]?[Z|[+-]hh:mm]] * * @param date ISO string to parse in the appropriate format. * @return the parsed date */ static Date parse(String date) throws JsonParseException { try { int offset = 0; // extract year int year = parseInt(date, offset, offset += 4); if (checkOffset(date, offset, '-')) { offset += 1; } // extract month int month = parseInt(date, offset, offset += 2); if (checkOffset(date, offset, '-')) { offset += 1; } // extract day int day = parseInt(date, offset, offset += 2); // default time value int hour = 0; int minutes = 0; int seconds = 0; int milliseconds = 0; // always use 0 otherwise returned date will include millis of current time // if the value has no time component (and no time zone), we are done boolean hasT = checkOffset(date, offset, 'T'); if (!hasT && (date.length() <= offset)) { Calendar calendar = new GregorianCalendar(year, month - 1, day); return calendar.getTime(); } if (hasT) { // extract hours, minutes, seconds and milliseconds hour = parseInt(date, offset += 1, offset += 2); if (checkOffset(date, offset, ':')) { offset += 1; } minutes = parseInt(date, offset, offset += 2); if (checkOffset(date, offset, ':')) { offset += 1; } // second and milliseconds can be optional if (date.length() > offset) { char c = date.charAt(offset); if (c != 'Z' && c != '+' && c != '-') { seconds = parseInt(date, offset, offset += 2); if (seconds > 59 && seconds < 63) seconds = 59; // truncate up to 3 leap seconds // milliseconds can be optional in the format if (checkOffset(date, offset, '.')) { offset += 1; int endOffset = indexOfNonDigit(date, offset + 1); // assume at least one digit int parseEndOffset = Math.min(endOffset, offset + 3); // parse up to 3 digits int fraction = parseInt(date, offset, parseEndOffset); milliseconds = (int) (Math.pow(10, 3 - (parseEndOffset - offset)) * fraction); offset = endOffset; } } } } // extract timezone if (date.length() <= offset) { throw new IllegalArgumentException("No time zone indicator"); } TimeZone timezone; char timezoneIndicator = date.charAt(offset); if (timezoneIndicator == 'Z') { timezone = TIMEZONE_Z; } else if (timezoneIndicator == '+' || timezoneIndicator == '-') { String timezoneOffset = date.substring(offset); // 18-Jun-2015, tatu: Minor simplification, skip offset of "+0000"/"+00:00" if ("+0000".equals(timezoneOffset) || "+00:00".equals(timezoneOffset)) { timezone = TIMEZONE_Z; } else { // 18-Jun-2015, tatu: Looks like offsets only work from GMT, not UTC... // not sure why, but it is what it is. String timezoneId = GMT_ID + timezoneOffset; timezone = TimeZone.getTimeZone(timezoneId); String act = timezone.getID(); if (!act.equals(timezoneId)) { /* 22-Jan-2015, tatu: Looks like canonical version has colons, but we may be given * one without. If so, don't sweat. * Yes, very inefficient. Hopefully not hit often. * If it becomes a perf problem, add 'loose' comparison instead. */ String cleaned = act.replace(":", ""); if (!cleaned.equals(timezoneId)) { throw new IndexOutOfBoundsException("Mismatching time zone indicator: " + timezoneId + " given, resolves to " + timezone.getID()); } } } } else { throw new IndexOutOfBoundsException("Invalid time zone indicator '" + timezoneIndicator + "'"); } Calendar calendar = new GregorianCalendar(timezone); calendar.setLenient(false); calendar.set(Calendar.YEAR, year); calendar.set(Calendar.MONTH, month - 1); calendar.set(Calendar.DAY_OF_MONTH, day); calendar.set(Calendar.HOUR_OF_DAY, hour); calendar.set(Calendar.MINUTE, minutes); calendar.set(Calendar.SECOND, seconds); calendar.set(Calendar.MILLISECOND, milliseconds); return calendar.getTime(); // If we get a ParseException it'll already have the right message/offset. // Other exception types can convert here. } catch (IndexOutOfBoundsException | IllegalArgumentException e) { throw new JsonParseException("Not an RFC 3339 date: " + date); } } /** * Check if the expected character exist at the given offset in the value. * * @param value the string to check at the specified offset * @param offset the offset to look for the expected character * @param expected the expected character * @return true if the expected character exist at the given offset */ private static boolean checkOffset(String value, int offset, char expected) { return (offset < value.length()) && (value.charAt(offset) == expected); } /** * Parse an integer located between 2 given offsets in a string * * @param value the string to parse * @param beginIndex the start index for the integer in the string * @param endIndex the end index for the integer in the string * @return the int * @throws NumberFormatException if the value is not a number */ private static int parseInt(String value, int beginIndex, int endIndex) throws NumberFormatException { if (beginIndex < 0 || endIndex > value.length() || beginIndex > endIndex) { throw new NumberFormatException(value); } // use same logic as in Integer.parseInt() but less generic we're not supporting negative values int i = beginIndex; int result = 0; int digit; if (i < endIndex) { digit = Character.digit(value.charAt(i++), 10); if (digit < 0) { throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex)); } result = -digit; } while (i < endIndex) { digit = Character.digit(value.charAt(i++), 10); if (digit < 0) { throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex)); } result *= 10; result -= digit; } return -result; } /** * Zero pad a number to a specified length * * @param buffer buffer to use for padding * @param value the integer value to pad if necessary. * @param length the length of the string we should zero pad */ private static void padInt(StringBuilder buffer, int value, int length) { String strValue = Integer.toString(value); for (int i = length - strValue.length(); i > 0; i--) { buffer.append('0'); } buffer.append(strValue); } /** * Returns the index of the first character in the string that is not a digit, starting at * offset. */ private static int indexOfNonDigit(String string, int offset) { for (int i = offset; i < string.length(); i++) { char c = string.charAt(i); if (c < '0' || c > '9') return i; } return string.length(); } }