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Diffstat (limited to 'simple/simple-http/src/main/java/org/simpleframework/http/parse/DateParser.java')
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diff --git a/simple/simple-http/src/main/java/org/simpleframework/http/parse/DateParser.java b/simple/simple-http/src/main/java/org/simpleframework/http/parse/DateParser.java new file mode 100644 index 0000000..7efea9c --- /dev/null +++ b/simple/simple-http/src/main/java/org/simpleframework/http/parse/DateParser.java @@ -0,0 +1,642 @@ +/* + * DateParser.java February 2001 + * + * Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net> + * + * 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 org.simpleframework.http.parse; + +import static java.util.Calendar.DAY_OF_MONTH; +import static java.util.Calendar.DAY_OF_WEEK; +import static java.util.Calendar.HOUR_OF_DAY; +import static java.util.Calendar.MILLISECOND; +import static java.util.Calendar.MINUTE; +import static java.util.Calendar.MONTH; +import static java.util.Calendar.SECOND; +import static java.util.Calendar.YEAR; + +import java.util.Calendar; +import java.util.TimeZone; + +import org.simpleframework.common.parse.Parser; + +/** + * This is used to create a <code>Parser</code> for the HTTP date format. + * This will parse the 3 formats that are acceptable for the HTTP/1.1 date. + * The three formats that are acceptable for the HTTP-date are + * <pre> + * Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123 + * Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036 + * Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format + * </pre> + * <p> + * This can also parse the date in ms as retrived from the <code>System</code>'s + * <code>System.currentTimeMillis</code> method. This has a parse method for a + * <code>long</code> which will do the same as the <code>parse(String)</code>. + * Once the date has been parsed there are two methods that allow the date + * to be represented, the <code>toLong</code> method converts the date to a + * <code>long</code> and the <code>toString</code> method will convert the date + * into a <code>String</code>. + * <p> + * This produces the same string as the <code>SimpleDateFormat.format</code> + * using the pattern <code>"EEE, dd MMM yyyy hh:mm:ss 'GMT'"</code>. This will + * however do the job faster as it does not take arbitrary inputs. + * + * @author Niall Gallagher + */ +public class DateParser extends Parser { + + /** + * Ensure that the time zone for dates if set to GMT. + */ + private static final TimeZone ZONE = TimeZone.getTimeZone("GMT"); + + /** + * Contains the possible days of the week for RFC 1123. + */ + private static final String WKDAYS[] = { "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun" }; + + /** + * Contains the possible days of the week for RFC 850. + */ + private static final String WEEKDAYS[] = { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday" }; + + /** + * Contains the possible months in the year for HTTP-date. + */ + private static final String MONTHS[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; + + /** + * Used as an index into the months array to get the month. + */ + private int month; + + /** + * Represents the decimal value of the date such as 1977. + */ + private int year; + + /** + * Represents the decimal value of the date such as 18. + */ + private int day; + + /** + * Used as an index into the weekdays array to get the weekday. + */ + private int weekday; + + /** + * Represents the decimal value of the hour such as 24. + */ + private int hour; + + /** + * Represents the decimal value of the minute. + */ + private int mins; + + /** + * Represents the decimal value for the second. + */ + private int secs; + + /** + * The default constructor will create a parser that can parse + * <code>String</code>s that contain dates in the form of RFC 1123, + * RFC 850 or asctime. If the dates that are to be parsed are not in + * the form of one of these date encodings the results of this + * parser will be random. + */ + public DateParser(){ + this.init(); + } + + /** + * This constructor will conveniently parse the <code>long</code> argument + * in the constructor. This can also be done by first calling the no-arg + * constructor and then using the parse method. + * <p> + * This will then set this object to one that uses the RFC 1123 format + * for a date. + * + * @param date the date to be parsed + */ + public DateParser(long date){ + this(); + parse(date); + } + + /** This constructor will conveniently parse the <code>String</code> + * argument in the constructor. This can also be done by first calling + * the no-arg constructor and then using the parse method. + * <p> + * This will then set this object to one that uses the RFC 1123 format + * for a date. + * + * @param date the date to be parsed + */ + public DateParser(String date) { + this(); + parse(date); + } + + /** + * This is used to extract the date from a <code>long</code>. If this + * method is given the value of the date as a <code>long</code> it will + * construct the RFC 1123 date as required by RFC 2616 sec 3.3. + * <p> + * This saves time on parsing a <code>String</code> that is encoded in + * the HTTP-date format. The date given must be positive, if the date + * given is not a positive '<code>long</code>' then the results + * of this method is random/unknown. + * + * @param date the date to be parsed + */ + public void parse(long date){ + Calendar calendar = Calendar.getInstance(ZONE); + calendar.setTimeInMillis(date); + + weekday = calendar.get(DAY_OF_WEEK); + year = calendar.get(YEAR); + month = calendar.get(MONTH); + day = calendar.get(DAY_OF_MONTH); + hour = calendar.get(HOUR_OF_DAY); + mins = calendar.get(MINUTE); + secs = calendar.get(SECOND); + month = month > 11 ? 11: month; + weekday = (weekday+5) % 7; + } + + /** + * Convenience method used to convert the specified HTTP date in to a + * long representing the time. This is used when a single method is + * required to convert a HTTP date format to a usable long value for + * use in creating <code>Date</code> objects. + * + * @param date the date specified in on of the HTTP date formats + * + * @return the date value as a long value in milliseconds + */ + public long convert(String date) { + parse(date); + return toLong(); + + } + + /** + * Convenience method used to convert the specified long date in to a + * HTTP date format. This is used when a single method is required to + * convert a long data value in milliseconds to a HTTP date value. + * + * @param date the date specified as a long of milliseconds + * + * @return the date represented in the HTTP date format RFC 1123 + */ + public String convert(long date) { + parse(date); + return toString(); + } + + /** + * This is used to reset the date and the buffer variables + * for this <code>DateParser</code>. Every in is set to the + * value of 0. + */ + protected void init() { + month = year = day = + weekday = hour = mins = + secs = off = 0; + } + + /** + * This is used to parse the contents of the <code>buf</code>. This + * checks the fourth char of the buffer to see what it contains. Invariably + * a date format belonging to RFC 1123 will have a ',' character in position 4, + * a date format belonging to asctime will have a ' ' character in position 4 + * and if neither of these characters are found at position 4 then it is + * assumed that the date is in the RFC 850 fromat, however it may not be. + */ + protected void parse(){ + if(buf.length<4)return; + if(buf[3]==','){ + rfc1123(); + }else if(buf[3]==' '){ + asctime(); + }else{ + rfc850(); + } + } + + /** + * This will parse a date that is in the form of an RFC 1123 date. This + * date format is the date format that is to be used with all applications + * that are HTTP/1.1 compliant. The RFC 1123 date format is + * <pre> + * rfc1123 = 'wkday "," SP date1 SP time SP GMT'. + * date1 = '2DIGIT SP month SP 4DIGIT' and finally + * time = '2DIGIT ":" 2DIGIT ":" 2DIGIT'. + * </pre> + */ + private void rfc1123(){ + wkday(); + off+=2; + date1(); + off++; + time(); + } + + /** + * This will parse a date that is in the form of an RFC 850 date. This date + * format is the date format that is to be used with some applications that + * are HTTP/1.0 compliant. The RFC 1123 date format is + * <pre> + * rfc850 = 'weekday "," SP date2 SP time SP GMT'. + * date2 = '2DIGIT "-" month "-" 2DIGIT' and finally + * time = '2DIGIT ":" 2DIGIT ":" 2DIGIT'. + * </pre> + */ + private void rfc850() { + weekday(); + off+=2; + date2(); + off++; + time(); + } + + /** + * This will parse a date that is in the form of an asctime date. This date + * format is the date format that is to be used with some applications that + * are HTTP/1.0 compliant. The RFC 1123 date format is + * <pre> + * asctime = 'weekday SP date3 SP time SP 4DIGIT'. + * date3 = 'month SP (2DIGIT | (SP 1DIGIT))' and + * time = '2DIGIT ":" 2DIGIT ":" 2DIGIT'. + * </pre> + */ + private void asctime(){ + wkday(); + off++; + date3(); + off++; + time(); + off++; + year4(); + } + + /** + * This is the date1 format of a date that is used by the RFC 1123 + * date format. This date is + * <pre> + * date1 = '2DIGIT SP month SP 4DIGIT'. + * example '02 Jun 1982'. + * </pre> + */ + private void date1(){ + day(); + off++; + month(); + off++; + year4(); + } + + /** + * This is the date2 format of a date that is used by the RFC 850 + * date format. This date is + * <pre> + * date2 = '2DIGIT "-" month "-" 2DIGIT' + * example '02-Jun-82'. + * </pre> + */ + private void date2(){ + day(); + off++; + month(); + off++; + year2(); + } + + /** + * This is the date3 format of a date that is used by the asctime + * date format. This date is + * <pre> + * date3 = 'month SP (2DIGIT | (SP 1DIGIT))' + * example 'Jun 2'. + * <pre> + */ + private void date3(){ + month(); + off++; + day(); + } + + /** + * This is used to parse a consecutive set of digit characters to create + * the day of the week. This will tolerate a space on front of the digits + * thiswill allow all date formats including asctime to use this to get + * the day. This may parse more than 2 digits, however if there are more + * than 2 digits the date format is incorrect anyway. + */ + private void day(){ + if(space(buf[off])){ + off++; + } + while(off < count){ + if(!digit(buf[off])){ + break; + } + day *= 10; + day += buf[off]; + day -= '0'; + off++; + } + } + + /** + * This is used to get the year from a set of digit characters. This is + * used to parse years that are of the form of 2 digits (e.g 82) however + * this will assume that any dates that are in 2 digit format are dates + * for the 2000 th milleneum so 01 will be 2001. + * <p> + * This may parse more than 2 digits but if there are more than 2 digits + * in a row then the date format is incorrect anyway. + */ + private void year2(){ + int mill = 2000; /* milleneum */ + int cent = 0; /* century */ + while(off < count){ + if(!digit(buf[off])){ + break; + } + cent *= 10; + cent += buf[off]; + cent -= '0'; + off++; + } + year= mill+cent; /* result 4 digits*/ + } + + /** + * This is used to get the year from a set of digit characters. This + * is used to parse years that are of the form of 4 digits (e.g 1982). + * <p> + * This may parse more than 4 digits but if there are more than 2 + * digits in a row then the date format is incorrect anyway. + */ + private void year4() { + while(off < count){ + if(!digit(buf[off])){ + break; + } + year *= 10; + year += buf[off]; + year -= '0'; + off++; + } + } + + /** + * This is used to parse the time for a HTTP-date. The time for a + * HTTP-date is in the form <code>00:00:00</code> that is + * <pre> + * time = '2DIGIT ":" 2DIGIT ":" 2DIGIT' so this will + * read only a time of that form, although this will + * parse time = '2DIGIT CHAR 2DIGIT CHAR 2DIGIT'. + * </pre> + */ + private void time(){ + hours(); + off++; + mins(); + off++; + secs(); + } + + /** + * This is used to initialize the hour. This will read a consecutive + * sequence of digit characters and convert them into a decimal number + * to represent the hour that this date represents. + * <p> + * This may parse more than 2 digits but if there are more than 2 + * digits the date is already incorrect. + */ + private void hours(){ + while(off < count){ + if(!digit(buf[off])){ + break; + } + hour *= 10; + hour += buf[off]; + hour -= '0'; + off++; + } + } + + /** + * This is used to initialize the mins. This will read a consecutive + * sequence of digit characters and convert them into a decimal number + * to represent the mins that this date represents. + * <p> + * This may parse more than 2 digits but if there are more than 2 + * digits the date is already incorrect. + */ + private void mins(){ + while(off < count){ + if(!digit(buf[off])){ + break; + } + mins *= 10; + mins += buf[off]; + mins -= '0'; + off++; + } + } + + /** + * This is used to initialize the secs. This will read a consecutive + * sequence of digit characters and convert them into a decimal + * number to represent the secs that this date represents. + * <p> + * This may parse more than 2 digits but if there are more than 2 + * digits the date is already incorrect + */ + private void secs(){ + while(off < count){ + if(!digit(buf[off])){ + break; + } + secs *= 10; + secs += buf[off]; + secs -= '0'; + off++; + } + } + + /** + * This is used to read the week day of HTTP-date. The shorthand day + * (e.g Mon for Monday) is used by the RFC 1123 and asctime date formats. + * This will simply try to read each day from the buffer, when the day + * is read successfully then the index of that day is saved. + */ + private void wkday(){ + for(int i =0; i < WKDAYS.length;i++){ + if(skip(WKDAYS[i])){ + weekday = i; + return; + } + } + } + + /** + * This is used to read the week day of HTTP-date. This format is used + * by the RFC 850 date format. This will simply try to read each day from + * the buffer, when the day is read successfully then the index of that + * day is saved. + */ + private void weekday(){ + for(int i =0; i < WKDAYS.length;i++){ + if(skip(WEEKDAYS[i])){ + weekday = i; + return; + } + } + } + + /** + * This is used to read the month of HTTP-date. This will simply + * try to read each month from the buffer, when the month is read + * successfully then the index of that month is saved. + */ + private void month(){ + for(int i =0; i < MONTHS.length;i++){ + if(skip(MONTHS[i])){ + month = i; + return; + } + } + } + + /** + * This is used to append the date in RFC 1123 format to the given + * string builder. This will append the date and a trailing space + * character to the buffer. Dates like the following are appended. + * <pre> + * Tue, 02 Jun 1982 + * </pre>. + * For performance reasons a string builder is used. This avoids + * an unneeded synchronization caused by the string buffers. + * + * @param builder this is the builder to append the date to + */ + private void date(StringBuilder builder) { + builder.append(WKDAYS[weekday]); + builder.append(", "); + + if(day <= 9) { + builder.append('0'); + } + builder.append(day); + builder.append(' '); + builder.append(MONTHS[month]); + builder.append(' '); + builder.append(year); + builder.append(' '); + } + + /** + * This is used to append the time in RFC 1123 format to the given + * string builder. This will append the time and a trailing space + * character to the buffer. Times like the following are appended. + * <pre> + * 23:59:59 + * </pre>. + * For performance reasons a string builder is used. This avoids + * an unneeded synchronization caused by the string buffers. + * + * @param builder this is the builder to write the time to + */ + private void time(StringBuilder builder) { + if(hour <= 9) { + builder.append('0'); + } + builder.append(hour); + builder.append(':'); + + if(mins <= 9) { + builder.append('0'); + } + builder.append(mins); + builder.append(':'); + + if(secs <= 9) { + builder.append('0'); + } + builder.append(secs); + builder.append(' '); + } + + /** + * This is used to append the time zone to the provided appender. + * For HTTP the dates should always be in GMT format. So this will + * simply append the "GMT" string to the end of the builder. + * + * @param builder this builder to append the time zone to + */ + private void zone(StringBuilder builder) { + builder.append("GMT"); + } + + /** + * This returns the date in as a <code>long</code>, given the exact + * time this will use the <code>java.util.Date</code> to parse this date + * into a <code>long</code>. The <code>GregorianCalendar</code> uses + * the method <code>getTime</code> which produces the <code>Date</code> + * object from this the <code>getTime</code> returns the <code>long</code> + * + * @return the date parsed as a <code>long</code> + */ + public long toLong() { + Calendar calendar = Calendar.getInstance(ZONE); /* GMT*/ + calendar.set(year,month, day, hour, mins, secs); + calendar.set(MILLISECOND, 0); + + return calendar.getTime().getTime(); + } + + /** + * This prints the date in the format of a RFC 1123 date. Example + * <pre> + * Tue, 02 Jun 1982 23:59:59 GMT + * </pre>. + * This uses a <code>StringBuffer</code> to accumulate the various + * <code>String</code>s/<code>int</code>s to form the resulting date + * value. The resulting date value is the one required by RFC 2616. + * <p> + * The HTTP date must be in the form of RFC 1123. The hours, minutes + * and seconds are appended with the 0 character if they are less than + * 9 i.e. if they do not have two digits. + * + * @return the date in RFC 1123 format + */ + public String toString(){ + StringBuilder builder = new StringBuilder(30); + + date(builder); + time(builder); + zone(builder); + + return builder.toString(); + } +} |