DateUtils (HAPI FHIR - Core Library 4.2.0 API)

java.lang.Object
- ca.uhn.fhir.util.DateUtils

```
public final class DateUtils
extends Object
```
A utility class for parsing and formatting HTTP dates as used in cookies and other headers. This class handles dates as defined by RFC 2616 section 3.3.1 as well as some other common non-standard formats.
This class is basically intended to be a high-performance workaround for the fact that Java SimpleDateFormat is kind of expensive to create and yet isn't thread safe.

This class was adapted from the class with the same name from the Jetty project, licensed under the terms of the Apache Software License 2.0.

Field Summary

Fields
Modifier and Type	Field	Description
`static TimeZone`	`GMT`	GMT TimeZone
`static String`	`PATTERN_ASCTIME`	Date format pattern used to parse HTTP date headers in ANSI C `asctime()` format.
`static String`	`PATTERN_RFC1036`	Date format pattern used to parse HTTP date headers in RFC 1036 format.
`static String`	`PATTERN_RFC1123`	Date format pattern used to parse HTTP date headers in RFC 1123 format.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static String`	`formatDate(Date date)`	Formats the given date according to the RFC 1123 pattern.
`static <T> T`	`notNull(T argument, String name)`
`static Date`	`parseDate(String theDateValue)`	Parses a date value.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - GMT
```
public static final TimeZone GMT
```
    GMT TimeZone
  - PATTERN_RFC1123
```
public static final String PATTERN_RFC1123
```
    Date format pattern used to parse HTTP date headers in RFC 1123 format.
    
    See Also:
    
    Constant Field Values
  - PATTERN_RFC1036
```
public static final String PATTERN_RFC1036
```
    Date format pattern used to parse HTTP date headers in RFC 1036 format.
    
    See Also:
    
    Constant Field Values
  - PATTERN_ASCTIME
```
public static final String PATTERN_ASCTIME
```
    Date format pattern used to parse HTTP date headers in ANSI C asctime() format.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - parseDate
```
public static Date parseDate(String theDateValue)
```
    Parses a date value. The formats used for parsing the date value are retrieved from the default http params.
    
    Parameters:
    
    theDateValue - the date value to parse
    
    Returns:
    
    the parsed date or null if input could not be parsed
  - formatDate
```
public static String formatDate(Date date)
```
    Formats the given date according to the RFC 1123 pattern.
    
    Parameters:
    
    date - The date to format.
    
    Returns:
    
    An RFC 1123 formatted date string.
    
    See Also:
    
    PATTERN_RFC1123
  - notNull
```
public static <T> T notNull(T argument,
                            String name)
```