Mega Code Archive
Handle obtaining string timestamps
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/**
* Copyright 2007 University Of Southern California
*
* 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.
*/
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Create a common interface to handle obtaining string timestamps.
* The difficult part is to allow for an ISO 8601 date formatting.
*
* @author Jens-S. Vöckler
* @author Yong Zhao
* @version $Revision: 379 $
*
* @see java.util.Date
* @see java.text.SimpleDateFormat
*/
public class Currently {
/**
* This is used to format the time stamp.
*/
private SimpleDateFormat m_formatter = null;
/**
* Default time format, which is compact and has a timezone
*/
public static final String DEFAULT_FORMAT = "yyyy.MM.dd HH:mm:ss zzz";
/**
* Default ctor: Create a new instance with a default formatting
* string for timestamps.
*/
public Currently() {
m_formatter = new SimpleDateFormat(DEFAULT_FORMAT);
}
/**
* Ctor: Create a new instance with a formatting string for time stamps.
* @param formatString complies to {@link java.text.SimpleDateFormat}.
*/
public Currently(String formatString) {
m_formatter = new SimpleDateFormat(formatString);
}
/**
* Ctor: Create a new instance with a formatting string for time stamps.
* @param format is a description of the simple date format to use.
*/
public Currently(SimpleDateFormat format) {
m_formatter = (SimpleDateFormat) format.clone();
}
/**
* Accessor: Obtains the default timestamp format for all queues.
*
* @return the currently active timestamp prefix format.
* @see #setDateFormat( String )
* @see #setDateFormat( SimpleDateFormat )
*/
public SimpleDateFormat getDateFormat() {
return m_formatter;
}
/**
* Accessor: Sets the default timestamp format for all queues.
*
* @param format is the new timestamp prefix format.
* @see #setDateFormat( SimpleDateFormat )
* @see #getDateFormat()
*/
public void setDateFormat(SimpleDateFormat format) {
if (format != null) {
m_formatter = format;
}
}
/**
* Accessor: Sets the default timestamp format for all queues.
*
* @param format is the new timestamp prefix format as a string.
* @see #setDateFormat( String )
* @see #getDateFormat()
*/
public void setDateFormat(String format) {
if (format != null) {
m_formatter = new SimpleDateFormat(format);
}
}
/**
* Obtains the current time as formatted string according to
* the format option.
* @return the current time as formatted string.
* @see #now( Date )
*/
public String now() {
return this.now(new Date());
}
/**
* Obtains the current time as formatted string according to
* the format option.
* @param then is a timestamp expressed as Date.
* @return the current time as formatted string.
* @see #now()
*/
public String now(Date then) {
return this.m_formatter.format(then);
}
/**
* Store the regular expressions necessary to parse ISO timestamps.
*/
private static final String c_expression[] = {
"([12][0-9]{3})-([01][0-9])-([0123][0-9])(T([012][0-9]):([0-6][0-9]):([0-6][0-9])?(\\.[0-9]+)?)?(Z|[-+][01][0-9]:?[0-6][0-9])?",
"([12][0-9]{3})([01][0-9])([0123][0-9])(T?([012][0-9])([0-6][0-9])([0-6][0-9])?(\\.[0-9]+)?)?(Z|[-+][01][0-9]:?[0-6][0-9])?"
};
/**
* Stores compiled patterns at first use, quasi-Singleton.
*/
private static Pattern c_pattern[] = null;
/**
* Parses one of the ISO 8601 that it produces. Note, it will not
* parse the full range of ISO timestamps.
*
* @param stamp is the textual timestamp representation.
* @return a time or <code>null</code>, if unparsable.
*/
public static Date parse(String stamp) {
// initialize the compiled expressions once
if (c_pattern == null) {
c_pattern = new Pattern[c_expression.length];
for (int i = 0; i < c_expression.length; ++i) {
c_pattern[i] = Pattern.compile(c_expression[i]);
}
}
// match against pattern
for (int i = 0; i < c_expression.length; ++i) {
Matcher m = c_pattern[i].matcher(stamp);
if (m.matches()) {
Calendar c = Calendar.getInstance();
TimeZone z = TimeZone.getDefault();
if (m.group(9) != null && m.group(9).length() > 0) {
boolean utc = (Character.toUpperCase(m.group(9).charAt(0)) == 'Z');
if (utc) {
z = TimeZone.getTimeZone("GMT+0");
} else {
z = TimeZone.getTimeZone("GMT" + m.group(9));
}
}
c.setTimeZone(z);
c.set(Calendar.YEAR, Integer.parseInt(m.group(1)));
c.set(Calendar.MONTH,
Integer.parseInt(m.group(2)) + (Calendar.JANUARY - 1));
c.set(Calendar.DAY_OF_MONTH, Integer.parseInt(m.group(3)));
if (m.group(4).length() > 0) {
c.set(Calendar.HOUR_OF_DAY, Integer.parseInt(m.group(5)));
c.set(Calendar.MINUTE, Integer.parseInt(m.group(6)));
if (m.group(7) != null && m.group(7).length() > 0) {
c.set(Calendar.SECOND, Integer.parseInt(m.group(7)));
}
if (m.group(8) != null && m.group(8).length() > 1) {
String millis = m.group(8).substring(1);
while (millis.length() < 3) {
millis += "0";
}
millis = millis.substring(0, 3);
c.set(Calendar.MILLISECOND, Integer.parseInt(millis));
}
}
return c.getTime();
}
}
// not found
return null;
}
/**
* Ignores any internal date format, and tries to show a complete
* date/timp stamp of the current time in extended ISO 8601 format.
* UTC time (Zulu time) or a local timezone will be used. A sample for
* UTC output is 2002-04-23T02:49:58Z A sample for local zone
* (CDT) is 2002-04-22T21:49:58-05:00
*
* @param zuluTime returns a UTC formatted stamp, if true. Otherwise
* the time will be formatted according to the local zone.
* @return an ISO 8601 formatted date and time representation for the
* current time in extended format without millisecond resolution
* @see #iso8601( boolean, boolean, boolean, Date )
*/
public static String iso8601(boolean zuluTime) {
return Currently.iso8601(zuluTime, true, false, new Date());
}
/**
* Ignores any internal date format, and tries to show a complete
* date/timp stamp in extended ISO 8601 format. UTC time (Zulu time)
* or a local timezone will be used.<p>
*
* <table border=1>
* <tr><th>zone</th><th>format</th><th>fraction</td><th>example</th></tr>
* <tr><td>local</td><td>basic</td><td>integral</td><td>20020523T140427-0500</td></tr>
* <tr><td>UTC</td><td>basic</td><td>integral</td><td>20020523190427Z</td></tr>
* <tr><td>local</td><td>extd.</td><td>integral</td><td>2002-05-23T14:04:27-05:00</td></tr>
* <tr><td>UTC</td><td>extd.</td><td>integral</td><td>2002-05-23T19:04:27Z</td></tr>
* <tr><td>local</td><td>basic</td><td>millis</td><td>20020523T140427.166-0500</td></tr>
* <tr><td>UTC</td><td>basic</td><td>millis</td><td>20020523190427.166Z</td></tr>
* <tr><td>local</td><td>extd.</td><td>millis</td><td>2002-05-23T14:04:27.166-05:00</td></tr>
* <tr><td>UTC</td><td>extd.</td><td>millis</td><td>2002-05-23T19:04:27.166Z</td></tr>
* </table><p>
*
* @param zuluTime returns a UTC formatted stamp, if true. Otherwise
* the time will be formatted according to the local zone. Local time
* should be prefixed with the 'T'.
* @param extendedFormat will use the extended ISO 8601 format which
* separates the different timestamp items. If false, the basic
* format will be used. In UTC and basic format, the 'T' separator
* will be omitted.
* @param withMillis will put the millisecond extension into the timestamp.
* If false, the time will be without millisecond fraction. The separator
* is taken from {@link java.text.DecimalFormatSymbols#getMinusSign()},
* which usually is a period or a comma.
* @param now is a time stamp as Date.
* @return an ISO 8601 formatted date and time representation for
* the given point in time.
*/
public static String iso8601(boolean zuluTime, boolean extendedFormat,
boolean withMillis, Date now) {
Calendar c =
Calendar.getInstance(zuluTime ?
TimeZone.getTimeZone("UTC") :
TimeZone.getDefault());
c.setTime(now);
// set up formattting options
DecimalFormat nf2 = new DecimalFormat("##00");
DecimalFormat nf3 = new DecimalFormat("###000");
DecimalFormat nf4 = new DecimalFormat("####0000");
DecimalFormatSymbols dfs = nf2.getDecimalFormatSymbols();
// allocate result string buffer
int size = extendedFormat ? (zuluTime ? 25 : 30) : (zuluTime ? 21 : 25);
if (!withMillis) {
size -= 4;
}
StringBuffer result = new StringBuffer(size);
result.append(nf4.format(c.get(Calendar.YEAR)));
if (extendedFormat) {
result.append('-'); // position 5
}
result.append(nf2.format(c.get(Calendar.MONTH) + 1));
if (extendedFormat) {
result.append('-'); // position 8
}
result.append(nf2.format(c.get(Calendar.DAY_OF_MONTH)));
// generating UTC in basic format may leave out the 'T' separator
if (extendedFormat || !zuluTime) {
result.append('T'); // position 11
}
result.append(nf2.format(c.get(Calendar.HOUR_OF_DAY)));
if (extendedFormat) {
result.append(':'); // position 14
}
result.append(nf2.format(c.get(Calendar.MINUTE)));
if (extendedFormat) {
result.append(':'); // position 17
}
result.append(nf2.format(c.get(Calendar.SECOND)));
if (withMillis) {
// Though there is no explicit spec which allows a complete
// timestamp with milliseconds, it is implied through two
// levels, sigh. 5.3.4.2 allows decimal fractions with
// time-only stamps that have a timezone. The intro of 5.4.2
// allows 5.3.1.3.
result.append(dfs.getDecimalSeparator()); // position 20
result.append(nf3.format(c.get(Calendar.MILLISECOND)));
}
if (zuluTime) {
// this is easy
result.append('Z');
} else {
// time zone calculations
int zone_offset = c.get(Calendar.ZONE_OFFSET) / 1000;
int save_offset = c.get(Calendar.DST_OFFSET) / 1000;
int diff = (zone_offset + save_offset) / 60;
result.append(diff < 0 ? dfs.getMinusSign() : '+'); // position 24
if (diff < 0) {
diff = Math.abs(diff);
}
result.append(nf2.format(diff / 60));
if (extendedFormat) {
result.append(':');
}
result.append(nf2.format(diff % 60));
}
return result.toString();
}
}
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