Mega Code Archive
A simple regular expression based parser for date notations
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package org.gwtwidgets.client.util;
import java.util.Date;
import org.gwtwidgets.client.util.regex.Pattern;
/**
* This is a simple regular expression based parser for date notations.
* While our aim is to fully support in the future the JDK date parser, currently
* only numeric notations and literals are supported such as <code>dd/MM/yyyy HH:mm:ss.SSSS</code>.
* Each entity is parsed with the same number of digits, i.e. for <code>dd</code> two digits will be
* parsed while for <code>d</code> only one will be parsed.
* @author <a href="mailto:g.georgovassilis@gmail.com">George Georgovassilis</a>
*
*/
public class SimpleDateParser {
private final static String DAY_IN_MONTH = "d";
private final static String MONTH = "M";
private final static String YEAR = "y";
private final static String LITERAL = "\\";
private final static int DATE_PATTERN = 0;
private final static int REGEX_PATTERN = 1;
private final static int COMPONENT = 2;
private final static int REGEX = 0;
private final static int INSTRUCTION = 1;
private final static String[] TOKENS[] = {
{ "SSSS", "(\\d\\d\\d\\d)",DateLocale.TOKEN_MILLISECOND },
{ "SSS", "(\\d\\d\\d)", DateLocale.TOKEN_MILLISECOND },
{ "SS", "(\\d\\d)", DateLocale.TOKEN_MILLISECOND },
{ "S", "(\\d)", DateLocale.TOKEN_MILLISECOND },
{ "ss", "(\\d\\d)", DateLocale.TOKEN_SECOND },
{ "s", "(\\d)", DateLocale.TOKEN_SECOND },
{ "mm", "(\\d\\d)", DateLocale.TOKEN_MINUTE },
{ "m", "(\\d)", DateLocale.TOKEN_MINUTE},
{ "HH", "(\\d\\d)", DateLocale.TOKEN_HOUR_24},
{ "H", "(\\d)", DateLocale.TOKEN_HOUR_24 },
{ "dd", "(\\d\\d)", DateLocale.TOKEN_DAY_OF_MONTH },
{ "d", "(\\d)", DateLocale.TOKEN_DAY_OF_MONTH },
{ "MM", "(\\d\\d)", DateLocale.TOKEN_MONTH },
{ "M", "(\\d)", DateLocale.TOKEN_MONTH },
{ "yyyy", "(\\d\\d\\d\\d)", DateLocale.TOKEN_YEAR },
{ "yyy", "(\\d\\d\\d)", DateLocale.TOKEN_YEAR },
{ "yy", "(\\d\\d)", DateLocale.TOKEN_YEAR },
{ "y", "(\\d)", DateLocale.TOKEN_YEAR }
};
private Pattern regularExpression;;
private String instructions = "";
private static void _parse(String format, String[] args) {
if (format.length() == 0)
return;
if (format.startsWith("'")){
format = format.substring(1);
int end = format.indexOf("'");
if (end == -1)
throw new IllegalArgumentException("Unmatched single quotes.");
args[REGEX]+=Pattern.quote(format.substring(0,end));
format = format.substring(end+1);
}
for (int i = 0; i < TOKENS.length; i++) {
String[] row = TOKENS[i];
String datePattern = row[DATE_PATTERN];
if (!format.startsWith(datePattern))
continue;
format = format.substring(datePattern.length());
args[REGEX] += row[REGEX_PATTERN];
args[INSTRUCTION] += row[COMPONENT];
_parse(format, args);
return;
}
args[REGEX] += Pattern.quote(""+format.charAt(0));
format = format.substring(1);
_parse(format, args);
}
private static void load(Date date, String text, String component) {
if (component.equals(DateLocale.TOKEN_MILLISECOND)) {
//TODO: implement
}
if (component.equals(DateLocale.TOKEN_SECOND)) {
date.setSeconds(Integer.parseInt(text));
}
if (component.equals(DateLocale.TOKEN_MINUTE)) {
date.setMinutes(Integer.parseInt(text));
}
if (component.equals(DateLocale.TOKEN_HOUR_24)) {
date.setHours(Integer.parseInt(text));
}
if (component.equals(DateLocale.TOKEN_DAY_OF_MONTH)) {
date.setDate(Integer.parseInt(text));
}
if (component.equals(DateLocale.TOKEN_MONTH)) {
date.setMonth(Integer.parseInt(text)-1);
}
if (component.equals(DateLocale.TOKEN_YEAR)) {
//TODO: fix for short patterns
date.setYear(Integer.parseInt(text)-1900);
}
}
public SimpleDateParser(String format) {
String[] args = new String[] { "", "" };
_parse(format, args);
regularExpression = new Pattern(args[REGEX]);
instructions = args[INSTRUCTION];
}
public Date parse(String input) {
Date date = new Date(0, 0, 0, 0, 0, 0);
String matches[] = regularExpression.match(input);
if (matches == null)
throw new IllegalArgumentException(input+" does not match "+regularExpression.pattern());
if (matches.length-1!=instructions.length())
throw new IllegalArgumentException("Different group count - "+input+" does not match "+regularExpression.pattern());
for (int group = 0; group < instructions.length(); group++) {
String match = matches[group + 1];
load(date, match, ""+instructions.charAt(group));
}
return date;
}
public static Date parse(String input, String pattern){
return new SimpleDateParser(pattern).parse(input);
}
}
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