java.lang.Object

org.rrd4j.core.Util

public class Util extends Object

Class defines various utility functions used in Rrd4j.

Author:: Sasa Markovic

Nested Class Summary

Nested Classes

Modifier and Type

Class

Description

static class

Util.Xml

Various DOM utility functions.
Field Summary

Fields

Modifier and Type

Field

Description

(package private) static final ThreadLocal<NumberFormat>

df

(package private) static final String

ISO_DATE_FORMAT

static final double

MAX_DOUBLE

Constant MAX_DOUBLE=Double.MAX_VALUE

static final long

MAX_LONG

Constant MAX_LONG=Long.MAX_VALUE

static final double

MIN_DOUBLE

Constant MIN_DOUBLE=-Double.MAX_VALUE

static final long

MIN_LONG

Constant MIN_LONG=-Long.MAX_VALUE

(package private) static final String

PATTERN

(package private) static final String

RRD4J_DIR
Method Summary

Modifier and Type

Method

Description

static boolean

equal(double x, double y)

Compares two doubles but treats all NaNs as equal.

static boolean

fileExists(String filename)

Checks if the file with the given file name exists

static String

formatDouble(double x)

Formats double as a string using exponential notation (RRDTool like).

(package private) static String

formatDouble(double x, boolean forceExponents)

(package private) static String

formatDouble(double x, String nanString, boolean forceExponents)

static Calendar

getCalendar(long timestamp)

Returns Calendar object for the given timestamp (in seconds, without milliseconds)

static Calendar

getCalendar(String timeStr)

Creates Calendar object from a string.

static Calendar

getCalendar(Date date)

Returns Calendar object for the given Date object

static String

getCanonicalPath(String path)

Returns canonical file path for the given file path

static Date

getDate(long timestamp)

Returns Date object for the given timestamp (in seconds, without milliseconds)

static String

getFileSeparator()

Returns file system separator string.

static String

getLapTime()

Function used for debugging purposes and performance bottlenecks detection.

static long

getLastModified(String file)

Deprecated.
use #getLastModifiedTime, that can throws exceptions if needed

static long

getLastModifiedTime(String file)

Returns last modification time for the given file.

(package private) static int

getMatchingArchiveIndex(RrdDb rrd1, int arcIndex, RrdDb rrd2)

(package private) static int

getMatchingDatasourceIndex(RrdDb rrd1, int dsIndex, RrdDb rrd2)

static String

getRrd4jDemoDirectory()

Returns path to directory used for placement of Rrd4j demo graphs and creates it if necessary.

static String

getRrd4jDemoPath(String filename)

Returns full path to the file stored in the demo directory of Rrd4j

static String

getRrd4jHomeDirectory()

Returns the root directory of the Rrd4j distribution.

static long

getTime()

Returns current timestamp in seconds (without milliseconds).

static long

getTimestamp()

Just an alias for getTime() method.

static long

getTimestamp(int year, int month, int day)

Returns timestamp (unix epoch) for the given year, month and day.

static long

getTimestamp(int year, int month, int day, int hour, int min)

Returns timestamp (unix epoch) for the given year, month, day, hour and minute.

static long

getTimestamp(String atStyleTimeSpec)

Parses at-style time specification and returns the corresponding timestamp.

static long

getTimestamp(Calendar gc)

Returns timestamp (unix epoch) for the given Calendar object

static long

getTimestamp(Date date)

Returns timestamp (unix epoch) for the given Date object

static long[]

getTimestamps(String atStyleTimeSpec1, String atStyleTimeSpec2)

Parses two related at-style time specifications and returns corresponding timestamps.

(package private) static String

getTmpFilename()

static String

getUserHomeDirectory()

Returns path to user's home directory.

static boolean

isDouble(String s)

Checks if a string can be parsed as double.

static double

max(double[] values)

Finds max value for an array of doubles (NaNs are ignored).

static double

max(double x, double y)

Returns the greater of two double values, but treats NaN as the smallest possible value.

static double

min(double[] values)

Finds min value for an array of doubles (NaNs are ignored).

static double

min(double x, double y)

Returns the smaller of two double values, but treats NaN as the greatest possible value.

static long

normalize(long timestamp, long step)

Rounds the given timestamp to the nearest whole "step".

static boolean

parseBoolean(String valueStr)

Parses input string as a boolean value.

static Paint

parseColor(String valueStr)

Parses input string as color.

static double

parseDouble(String valueStr)

Parses input string as a double value.

(package private) static boolean

sameFilePath(String pathname1, String pathname2)

static String

sprintf(Locale l, String format, Object... args)

Equivalent of the C-style sprintf function.

static double

sum(double x, double y)

Calculates sum of two doubles, but treats NaNs as zeros.

static double[]

toDoubleArray(long[] array)

Converts an array of long primitives to an array of doubles.

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

Field Details
- MAX_LONG
  
  public static final long MAX_LONG
  
  Constant MAX_LONG=Long.MAX_VALUE
  See Also:
  
  Constant Field Values
- MIN_LONG
  
  public static final long MIN_LONG
  
  Constant MIN_LONG=-Long.MAX_VALUE
  See Also:
  
  Constant Field Values
- MAX_DOUBLE
  
  public static final double MAX_DOUBLE
  
  Constant MAX_DOUBLE=Double.MAX_VALUE
  See Also:
  
  Constant Field Values
- MIN_DOUBLE
  
  public static final double MIN_DOUBLE
  
  Constant MIN_DOUBLE=-Double.MAX_VALUE
  See Also:
  
  Constant Field Values
- PATTERN
  
  static final String PATTERN
  See Also:
  
  Constant Field Values
- RRD4J_DIR
  
  static final String RRD4J_DIR
  See Also:
  
  Constant Field Values
- df
  
  static final ThreadLocal<NumberFormat> df
- ISO_DATE_FORMAT
  
  static final String ISO_DATE_FORMAT
  See Also:
  
  Constant Field Values
Method Details
- toDoubleArray
  
  public static double[] toDoubleArray(long[] array)
  
  Converts an array of long primitives to an array of doubles.
  
  Parameters:
  
  array - input array of long values.
  
  Returns:
  
  Same array but with all values as double.
- getTime
  
  public static long getTime()
  
  Returns current timestamp in seconds (without milliseconds). Returned timestamp is obtained with the following expression:
  (System.currentTimeMillis() + 500L) / 1000L
  
  Returns:
  
  Current timestamp
- getTimestamp
  
  public static long getTimestamp()
  
  Just an alias for getTime() method.
  
  Returns:
  
  Current timestamp (without milliseconds)
- normalize
  
  public static long normalize(long timestamp, long step)
  
  Rounds the given timestamp to the nearest whole "step". Rounded value is obtained from the following expression:
  timestamp - timestamp % step;
  
  Parameters:
  
  timestamp - Timestamp in seconds
  
  step - Step in seconds
  
  Returns:
  
  "Rounded" timestamp
- max
  
  public static double max(double x, double y)
  
  Returns the greater of two double values, but treats NaN as the smallest possible value. Note that Math.max() behaves differently for NaN arguments.
  
  Parameters:
  
  x - an argument
  
  y - another argument
  
  Returns:
  
  the lager of arguments
- min
  
  public static double min(double x, double y)
  
  Returns the smaller of two double values, but treats NaN as the greatest possible value. Note that Math.min() behaves differently for NaN arguments.
  
  Parameters:
  
  x - an argument
  
  y - another argument
  
  Returns:
  
  the smaller of arguments
- sum
  
  public static double sum(double x, double y)
  
  Calculates sum of two doubles, but treats NaNs as zeros.
  
  Parameters:
  
  x - First double
  
  y - Second double
  
  Returns:
  
  Sum(x,y) calculated as Double.isNaN(x)? y: Double.isNaN(y)? x: x + y;
- formatDouble
  
  static String formatDouble(double x, String nanString, boolean forceExponents)
- formatDouble
  
  static String formatDouble(double x, boolean forceExponents)
- formatDouble
  
  public static String formatDouble(double x)
  
  Formats double as a string using exponential notation (RRDTool like). Used for debugging through the project.
  
  Parameters:
  
  x - value to be formatted
  
  Returns:
  
  string like "+1.234567E+02"
- getDate
  
  public static Date getDate(long timestamp)
  
  Returns Date object for the given timestamp (in seconds, without milliseconds)
  
  Parameters:
  
  timestamp - Timestamp in seconds.
  
  Returns:
  
  Corresponding Date object.
- getCalendar
  
  public static Calendar getCalendar(long timestamp)
  
  Returns Calendar object for the given timestamp (in seconds, without milliseconds)
  
  Parameters:
  
  timestamp - Timestamp in seconds.
  
  Returns:
  
  Corresponding Calendar object.
- getCalendar
  
  public static Calendar getCalendar(Date date)
  
  Returns Calendar object for the given Date object
  
  Parameters:
  
  date - Date object
  
  Returns:
  
  Corresponding Calendar object.
- getTimestamp
  
  public static long getTimestamp(Date date)
  
  Returns timestamp (unix epoch) for the given Date object
  
  Parameters:
  
  date - Date object
  
  Returns:
  
  Corresponding timestamp (without milliseconds)
- getTimestamp
  
  public static long getTimestamp(Calendar gc)
  
  Returns timestamp (unix epoch) for the given Calendar object
  
  Parameters:
  
  gc - Calendar object
  
  Returns:
  
  Corresponding timestamp (without milliseconds)
- getTimestamp
  
  public static long getTimestamp(int year, int month, int day, int hour, int min)
  
  Returns timestamp (unix epoch) for the given year, month, day, hour and minute.
  The date is resolved in the current time zone
  
  Parameters:
  
  year - Year
  
  month - Month (zero-based)
  
  day - Day in month
  
  hour - Hour
  
  min - Minute
  
  Returns:
  
  Corresponding timestamp
- getTimestamp
  
  public static long getTimestamp(int year, int month, int day)
  
  Returns timestamp (unix epoch) for the given year, month and day.
  The date is resolved in the current time zone
  
  Parameters:
  
  year - Year
  
  month - Month (zero-based)
  
  day - Day in month
  
  Returns:
  
  Corresponding timestamp
- getTimestamp
  
  public static long getTimestamp(String atStyleTimeSpec)
  Parses at-style time specification and returns the corresponding timestamp. For example:
  
  long t = Util.getTimestamp("now-1d");
  Parameters:
  
  atStyleTimeSpec - at-style time specification. For the complete explanation of the syntax allowed see RRDTool's rrdfetch man page.
  
  Returns:
  
  timestamp in seconds since epoch.
- getTimestamps
  
  public static long[] getTimestamps(String atStyleTimeSpec1, String atStyleTimeSpec2)
  Parses two related at-style time specifications and returns corresponding timestamps. For example:
  
  long[] t = Util.getTimestamps("end-1d","now");
  Parameters:
  
  atStyleTimeSpec1 - Starting at-style time specification. For the complete explanation of the syntax allowed see RRDTool's rrdfetch man page.
  
  atStyleTimeSpec2 - Ending at-style time specification. For the complete explanation of the syntax allowed see RRDTool's rrdfetch man page.
  
  Returns:
  
  An array of two longs representing starting and ending timestamp in seconds since epoch.
- parseDouble
  
  public static double parseDouble(String valueStr)
  
  Parses input string as a double value. If the value cannot be parsed, Double.NaN is returned (NumberFormatException is never thrown).
  
  Parameters:
  
  valueStr - String representing double value
  
  Returns:
  
  a double corresponding to the input string
- isDouble
  
  public static boolean isDouble(String s)
  
  Checks if a string can be parsed as double.
  
  Parameters:
  
  s - Input string
  
  Returns:
  
  true if the string can be parsed as double, false otherwise
- parseBoolean
  
  public static boolean parseBoolean(String valueStr)
  
  Parses input string as a boolean value. The parser is case insensitive.
  
  Parameters:
  
  valueStr - String representing boolean value
  
  Returns:
  
  true, if valueStr equals to 'true', 'on', 'yes', 'y' or '1'; false in all other cases.
- parseColor
  
  public static Paint parseColor(String valueStr)
  
  Parses input string as color. The color string should be of the form #RRGGBB (no alpha specified, opaque color) or #RRGGBBAA (alpa specified, transparent colors). Leading character '#' is optional.
  
  Parameters:
  
  valueStr - Input string, for example #FFAA24, #AABBCC33, 010203 or ABC13E4F
  
  Returns:
  
  Paint object
  
  Throws:
  
  IllegalArgumentException - If the input string is not 6 or 8 characters long (without optional '#')
- getFileSeparator
  
  public static String getFileSeparator()
  
  Returns file system separator string.
  
  Returns:
  
  File system separator ("/" on Unix, "\" on Windows)
- getUserHomeDirectory
  
  public static String getUserHomeDirectory()
  
  Returns path to user's home directory.
  
  Returns:
  
  Path to users home directory, with file separator appended.
- getRrd4jDemoDirectory
  
  public static String getRrd4jDemoDirectory()
  
  Returns path to directory used for placement of Rrd4j demo graphs and creates it if necessary.
  
  Returns:
  
  Path to demo directory (defaults to $HOME/rrd4j/) if directory exists or was successfully created. Null if such directory could not be created.
- getRrd4jDemoPath
  
  public static String getRrd4jDemoPath(String filename)
  
  Returns full path to the file stored in the demo directory of Rrd4j
  
  Parameters:
  
  filename - Partial path to the file stored in the demo directory of Rrd4j (just name and extension, without parent directories)
  
  Returns:
  
  Full path to the file
- sameFilePath
  
  static boolean sameFilePath(String pathname1, String pathname2) throws IOException
  
  Throws:
  
  IOException
- getMatchingDatasourceIndex
  
  static int getMatchingDatasourceIndex(RrdDb rrd1, int dsIndex, RrdDb rrd2) throws IOException
  
  Throws:
  
  IOException
- getMatchingArchiveIndex
  
  static int getMatchingArchiveIndex(RrdDb rrd1, int arcIndex, RrdDb rrd2) throws IOException
  
  Throws:
  
  IOException
- getTmpFilename
  
  static String getTmpFilename() throws IOException
  
  Throws:
  
  IOException
- getCalendar
  
  public static Calendar getCalendar(String timeStr)
  
  Creates Calendar object from a string. The string should represent either a long integer (UNIX timestamp in seconds without milliseconds, like "1002354657") or a human readable date string in the format "yyyy-MM-dd HH:mm:ss" (like "2004-02-25 12:23:45").
  
  Parameters:
  
  timeStr - Input string
  
  Returns:
  
  Calendar object
- getLapTime
  
  public static String getLapTime()
  
  Function used for debugging purposes and performance bottlenecks detection. Probably of no use for end users of Rrd4j.
  
  Returns:
  
  String representing time in seconds since last getLapTime() method call.
- getRrd4jHomeDirectory
  
  public static String getRrd4jHomeDirectory()
  
  Returns the root directory of the Rrd4j distribution. Useful in some demo applications, probably of no use anywhere else.
  
  The function assumes that all Rrd4j .class files are placed under the <root>/classes subdirectory and that all jars (libraries) are placed in the <root>/lib subdirectory (the original Rrd4j directory structure).
  
  Returns:
  
  absolute path to Rrd4j's home directory
- equal
  
  public static boolean equal(double x, double y)
  
  Compares two doubles but treats all NaNs as equal. In Java (by default) Double.NaN == Double.NaN always returns false
  
  Parameters:
  
  x - the first value
  
  y - the second value
  
  Returns:
  
  true if x and y are both equal to Double.NaN, or if x == y. false otherwise
- getCanonicalPath
  
  public static String getCanonicalPath(String path) throws IOException
  
  Returns canonical file path for the given file path
  
  Parameters:
  
  path - Absolute or relative file path
  
  Returns:
  
  Canonical file path
  
  Throws:
  
  IOException - Thrown if canonical file path could not be resolved
- getLastModified
  
  @Deprecated public static long getLastModified(String file)
  
  Deprecated.
  use #getLastModifiedTime, that can throws exceptions if needed
  
  Returns last modification time for the given file.
  
  Parameters:
  
  file - File object representing file on the disk
  
  Returns:
  
  Last modification time in seconds (without milliseconds)
- getLastModifiedTime
  
  public static long getLastModifiedTime(String file) throws IOException
  
  Returns last modification time for the given file.
  
  Parameters:
  
  file - File object representing file on the disk
  
  Returns:
  
  Last modification time in seconds (without milliseconds)
  
  Throws:
  
  IOException
- fileExists
  
  public static boolean fileExists(String filename)
  
  Checks if the file with the given file name exists
  
  Parameters:
  
  filename - File name
  
  Returns:
  
  true if file exists, false otherwise
- max
  
  public static double max(double[] values)
  
  Finds max value for an array of doubles (NaNs are ignored). If all values in the array are NaNs, NaN is returned.
  
  Parameters:
  
  values - Array of double values
  
  Returns:
  
  max value in the array (NaNs are ignored)
- min
  
  public static double min(double[] values)
  
  Finds min value for an array of doubles (NaNs are ignored). If all values in the array are NaNs, NaN is returned.
  
  Parameters:
  
  values - Array of double values
  
  Returns:
  
  min value in the array (NaNs are ignored)
- sprintf
  
  public static String sprintf(Locale l, String format, Object... args)
  
  Equivalent of the C-style sprintf function.
  
  Parameters:
  
  l - a Locale object.
  
  format - Format string
  
  args - Arbitrary list of arguments
  
  Returns:
  
  Formatted string

Class Util

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Details

MAX_LONG

MIN_LONG

MAX_DOUBLE

MIN_DOUBLE

PATTERN

RRD4J_DIR

df

ISO_DATE_FORMAT

Method Details

toDoubleArray

getTime

getTimestamp

normalize

max

min

sum

formatDouble

formatDouble

formatDouble

getDate

getCalendar

getCalendar

getTimestamp

getTimestamp

getTimestamp

getTimestamp

getTimestamp

getTimestamps

parseDouble

isDouble

parseBoolean

parseColor

getFileSeparator

getUserHomeDirectory

getRrd4jDemoDirectory

getRrd4jDemoPath

sameFilePath

getMatchingDatasourceIndex

getMatchingArchiveIndex

getTmpFilename

getCalendar

getLapTime

getRrd4jHomeDirectory

equal

getCanonicalPath

getLastModified

getLastModifiedTime

fileExists

max

min

sprintf