# Class DateFormatCache

java.lang.Object
org.apache.juli.DateFormatCache

public class DateFormatCache extends Object

Cache structure for SimpleDateFormat formatted timestamps based on seconds.

Millisecond formatting using S is not supported. You should add the millisecond information after getting back the second formatting.

The cache consists of entries for a consecutive range of seconds. The length of the range is configurable. It is implemented based on a cyclic buffer. New entries shift the range.

The cache is not thread safe. It can be used without synchronization via thread local instances, or with synchronization as a global cache.

The cache can be created with a parent cache to build a cache hierarchy. Access to the parent cache is thread safe.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final char`
  `MSEC_PATTERN`
  Pattern character used to replace 'S' (milliseconds) in format strings to make timestamps cacheable.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `DateFormatCache(int size, String format, DateFormatCache parent)`
  Create a new DateFormatCache.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `String`
  `getFormat(long time)`
  Get the formatted timestamp for the given time.
  `String`
  `getTimeFormat()`
  Get the time format string used by this cache.
  `protected static String`
  `tidyFormat(String format)`
  Replace the millisecond formatting character 'S' by some dummy characters in order to make the resulting formatted time stamps cacheable.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### MSEC_PATTERN

    public static final char MSEC_PATTERN
    Pattern character used to replace 'S' (milliseconds) in format strings to make timestamps cacheable.
    See Also:
      - Constant Field Values

- ## Constructor Details

  - ### DateFormatCache

    public DateFormatCache(int size, String format, DateFormatCache parent)
    Create a new DateFormatCache.
    Parameters:
      `size` - The number of cached entries
      `format` - The timestamp format string
      `parent` - The parent cache for building a cache hierarchy

- ## Method Details

  - ### tidyFormat

    protected static String tidyFormat(String format)
    Replace the millisecond formatting character 'S' by some dummy characters in order to make the resulting formatted time stamps cacheable. Our consumer might choose to replace the dummy chars with the actual milliseconds because that's relatively cheap.
    Parameters:
      `format` - the format
    Returns:
      the replacement format

  - ### getFormat

    public String getFormat(long time)
    Get the formatted timestamp for the given time.
    Parameters:
      `time` - The time in milliseconds
    Returns:
      the formatted timestamp string

  - ### getTimeFormat

    public String getTimeFormat()
    Get the time format string used by this cache.
    Returns:
      the time format string