it.unimi.dsi

Class Util

java.lang.Object

it.unimi.dsi.Util

public final class Util
extends Object

All-purpose static-method container class.

Since:

0.1

Author:

Sebastiano Vigna

Method Summary

Methods

Modifier and Type	Method and Description
static long	availableMemory() Returns the amount of available memory (free memory plus never allocated memory).
static void	compactMemory() Tries to compact memory as much as possible by forcing garbage collection.
static void	ensureLog4JIsConfigured() Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to Level.INFO.
static void	ensureLog4JIsConfigured(Class<?> klass) Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to Level.INFO.
static void	ensureLog4JIsConfigured(Class<?> klass, org.apache.log4j.Level level) Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to level.
static void	ensureLog4JIsConfigured(org.apache.log4j.Level level) Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to a specified logging level.
static String	format(double d) Formats a number.
static String	format(long l) Formats a number.
static String	formatBinarySize(long l) Formats a binary size.
static String	formatSize(long l) Formats a size.
static org.apache.log4j.Logger	getDebugLogger(Class<?> klass) Calls Log4J's Logger.getLogger(java.lang.Class) method and then ensureLog4JIsConfigured() with argument Level.DEBUG.
static org.apache.log4j.Logger	getLogger(Class<?> klass) Calls Log4J's Logger.getLogger(java.lang.Class) method and then ensureLog4JIsConfigured().
static boolean	log4JIsConfigured() Checks whether Log4J is properly configuring by searching for appenders in all loggers.
static boolean	memoryIsLow() Returns true if less then 5% of the available memory is free.
static int	percAvailableMemory() Returns the percentage of available memory (free memory plus never allocated memory).

Methods inherited from class java.lang.Object

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

Method Detail

format

public static String format(double d)

Formats a number.

This method formats a double separating thousands and printing just two fractional digits.

Parameters:

d - a number.

Returns:

a string containing a pretty print of the number.

format

public static String format(long l)

Formats a number.

This method formats a long separating thousands.

Parameters:

l - a number.

Returns:

a string containing a pretty print of the number.

formatSize

public static String formatSize(long l)

Formats a size.

This method formats a long using suitable unit multipliers (e.g., K, M, G, and T) and printing just two fractional digits.

Parameters:

l - a number, representing a size (e.g., memory).

Returns:

a string containing a pretty print of the number using unit multipliers.

formatBinarySize

public static String formatBinarySize(long l)

Formats a binary size.

This method formats a long using suitable unit binary multipliers (e.g., Ki, Mi, Gi, and Ti) and printing no fractional digits. The argument must be a power of 2.

Parameters:

l - a number, representing a binary size (e.g., memory); must be a power of 2.

Returns:

a string containing a pretty print of the number using binary unit multipliers.

log4JIsConfigured

public static boolean log4JIsConfigured()

Checks whether Log4J is properly configuring by searching for appenders in all loggers.

Returns:

whether Log4J is configured (or, at least, an educated guess).

ensureLog4JIsConfigured

public static void ensureLog4JIsConfigured(Class<?> klass)

Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to Level.INFO.

Parameters:

klass - the calling class (to be shown to the user).

ensureLog4JIsConfigured

public static void ensureLog4JIsConfigured(Class<?> klass,
                           org.apache.log4j.Level level)

Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to level.

Parameters:

klass - the calling class (to be shown to the user).

level - the required logging level.

ensureLog4JIsConfigured

public static void ensureLog4JIsConfigured()

Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to Level.INFO.

ensureLog4JIsConfigured

public static void ensureLog4JIsConfigured(org.apache.log4j.Level level)

Ensures that Log4J is configured, by invoking, if necessary, BasicConfigurator.configure(), and setting the root logger level to a specified logging level.

Parameters:

level - the required logging level.

getLogger

public static org.apache.log4j.Logger getLogger(Class<?> klass)

Calls Log4J's Logger.getLogger(java.lang.Class) method and then ensureLog4JIsConfigured().

Parameters:

klass - a class that will be passed to Logger.getLogger(java.lang.Class).

Returns:

the logger returned by Logger.getLogger(java.lang.Class).

getDebugLogger

public static org.apache.log4j.Logger getDebugLogger(Class<?> klass)

Calls Log4J's Logger.getLogger(java.lang.Class) method and then ensureLog4JIsConfigured() with argument Level.DEBUG.

Parameters:

klass - a class that will be passed to Logger.getLogger(java.lang.Class).

Returns:

the logger returned by Logger.getLogger(java.lang.Class).

memoryIsLow

public static boolean memoryIsLow()

Returns true if less then 5% of the available memory is free.

Returns:

true if less then 5% of the available memory is free.

availableMemory

public static long availableMemory()

Returns the amount of available memory (free memory plus never allocated memory).

Returns:

the amount of available memory, in bytes.

percAvailableMemory

public static int percAvailableMemory()

Returns the percentage of available memory (free memory plus never allocated memory).

Returns:

the percentage of available memory.

compactMemory

public static void compactMemory()

Tries to compact memory as much as possible by forcing garbage collection.