Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.util.*;

public class Main {
    /**
     * ID to represent the 'GMT' string
     */
    private static final String GMT_ID = "GMT";

    /**
     * Parse a date from ISO-8601 formatted string. It expects a format yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]
     *
     * @param date ISO string to parse in the appropriate format.
     * @return the parsed date
     * @throws IllegalArgumentException if the date is not in the appropriate format
     */
    public static Date parse(String date) {
        try {
            int offset = 0;

            // extract year
            int year = parseInt(date, offset, offset += 4);
            checkOffset(date, offset, '-');

            // extract month
            int month = parseInt(date, offset += 1, offset += 2);
            checkOffset(date, offset, '-');

            // extract day
            int day = parseInt(date, offset += 1, offset += 2);
            checkOffset(date, offset, 'T');

            // extract hours, minutes, seconds and milliseconds
            int hour = parseInt(date, offset += 1, offset += 2);
            checkOffset(date, offset, ':');

            int minutes = parseInt(date, offset += 1, offset += 2);
            checkOffset(date, offset, ':');

            int seconds = parseInt(date, offset += 1, offset += 2);
            // milliseconds can be optional in the format
            int milliseconds = 0; // always use 0 otherwise returned date will include millis of current time
            if (date.charAt(offset) == '.') {
                checkOffset(date, offset, '.');
                milliseconds = parseInt(date, offset += 1, offset += 3);
            }

            // extract timezone
            String timezoneId;
            char timezoneIndicator = date.charAt(offset);
            if (timezoneIndicator == '+' || timezoneIndicator == '-') {
                timezoneId = GMT_ID + date.substring(offset);
            } else if (timezoneIndicator == 'Z') {
                timezoneId = GMT_ID;
            } else {
                throw new IndexOutOfBoundsException("Invalid time zone indicator " + timezoneIndicator);
            }
            TimeZone timezone = TimeZone.getTimeZone(timezoneId);
            if (!timezone.getID().equals(timezoneId)) {
                throw new IndexOutOfBoundsException();
            }

            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();
        } catch (IndexOutOfBoundsException e) {
            throw new IllegalArgumentException("Failed to parse date " + date, e);
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Failed to parse date " + date, e);
        } catch (IllegalArgumentException e) {
            throw new IllegalArgumentException("Failed to parse date " + date, e);
        }
    }

    /**
     * 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);
            }
            result = -digit;
        }
        while (i < endIndex) {
            digit = Character.digit(value.charAt(i++), 10);
            if (digit < 0) {
                throw new NumberFormatException("Invalid number: " + value);
            }
            result *= 10;
            result -= digit;
        }
        return -result;
    }

    /**
     * Check if the expected character exist at the given offset of the
     *
     * @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
     * @throws IndexOutOfBoundsException if the expected character is not found
     */
    private static void checkOffset(String value, int offset, char expected) throws IndexOutOfBoundsException {
        char found = value.charAt(offset);
        if (found != expected) {
            throw new IndexOutOfBoundsException("Expected '" + expected + "' character but found '" + found + "'");
        }
    }
}