Package net.sf.freecol.common.util

Class Utils

java.lang.Object

net.sf.freecol.common.util.Utils

public class Utils
extends java.lang.Object

Collection of small static helper methods.

Field Summary

Fields

Modifier and Type	Field	Description
private static java.lang.String	HEX_DIGITS	Hex constant digits for get/restoreRandomState.
private static java.util.logging.Logger	logger

Constructor Summary

Constructors

Constructor	Description
Utils()

Method Summary

Modifier and Type	Method	Description
static void	delay(long ms, java.lang.String warning)	Delay by a number of milliseconds.
static void	deleteFile(java.io.File file)	Delete a file.
static void	deleteFiles(java.util.List<java.io.File> files)	Delete a list of files.
static int	determineDpi(java.awt.GraphicsDevice gd)	Tries to determine the DPI of the given GraphicsDevice.
static boolean	directoryAllPresent(java.io.File dir, java.lang.String... names)	Does a directory contain the given file/s?
static <T> boolean	equals(T one, T two)	Check if two objects are equal but also checks for null.
static boolean	fileAnySuffix(java.io.File file, java.lang.String... suffixes)	Does a readable file have a matching suffix?
static void	garbageCollect()	Run the garbage collector.
private static java.io.Writer	getF8W(java.io.File file, boolean append)	Create a new file writer that uses UTF-8.
static java.io.Writer	getFileUTF8AppendWriter(java.io.File file)	Create a new appending file writer that uses UTF-8.
static java.io.Reader	getFileUTF8Reader(java.io.File file)	Create a new file reader that uses UTF-8.
static java.io.Writer	getFileUTF8Writer(java.io.File file)	Create a new file writer that uses UTF-8.
static java.awt.GraphicsDevice	getGoodGraphicsDevice()	Get a good screen device for starting FreeCol.
static java.lang.String	getRandomState(java.util.Random random)	Get the internal state of a random number generator as a string.
static java.lang.String	getUTF8Contents(java.io.File file)	Get the UTF-8 encoded contents of a file.
static java.io.Writer	getUTF8Writer(java.io.OutputStream os)	Create a new file writer that uses UTF-8.
static int	hashCode(java.lang.Object object)	Get a hash code for an object, even null.
static boolean	isHeadless()	Are we in headless mode?
static javax.xml.transform.Transformer	makeTransformer(boolean declaration, boolean indent)	Helper to make an XML Transformer.
static long	now()	Current time since epoch in milliseconds.
static java.util.Random	restoreRandomState(java.lang.String state)	Restore a previously saved state.

Methods inherited from class java.lang.Object

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

Field Detail

logger

private static final java.util.logging.Logger logger

HEX_DIGITS

private static final java.lang.String HEX_DIGITS

Hex constant digits for get/restoreRandomState.

See Also:

Constant Field Values

Constructor Detail

Utils

public Utils()

Method Detail

equals

public static <T> boolean equals(T one,
                                 T two)

Check if two objects are equal but also checks for null.

Type Parameters:

T - The object type.

Parameters:

one - First object to compare

two - Second object to compare

Returns:

True if the arguments are either both null or equal in the sense of their equals() method.

hashCode

public static int hashCode(java.lang.Object object)

Get a hash code for an object, even null.

Parameters:

object - The Object to use.

Returns:

A hash code.

getRandomState

public static java.lang.String getRandomState(java.util.Random random)
                                       throws java.io.IOException

Get the internal state of a random number generator as a string. It would have been more convenient to simply return the current seed, but unfortunately it is private.

Parameters:

random - A pseudo-random number source.

Returns:

A String encapsulating the object state.

Throws:

java.io.IOException - is the byte stream output breaks.

restoreRandomState

public static java.util.Random restoreRandomState(java.lang.String state)

Restore a previously saved state.

Parameters:

state - The saved state (@see #getRandomState()).

Returns:

The restored Random.

getFileUTF8Reader

public static java.io.Reader getFileUTF8Reader(java.io.File file)

Create a new file reader that uses UTF-8.

Parameters:

file - A File to read from.

Returns:

A Reader for this file.

getUTF8Contents

public static java.lang.String getUTF8Contents(java.io.File file)

Get the UTF-8 encoded contents of a file.

Parameters:

file - The File to query.

Returns:

The contents string, or null on error.

getUTF8Writer

public static java.io.Writer getUTF8Writer(java.io.OutputStream os)

Create a new file writer that uses UTF-8.

Parameters:

os - An OutputStream to write to.

Returns:

A Writer for this file.

getF8W

private static java.io.Writer getF8W(java.io.File file,
                                     boolean append)

Create a new file writer that uses UTF-8.

Parameters:

file - A File to write to.

append - If true, append to the file.

Returns:

A Writer for this file.

getFileUTF8Writer

public static java.io.Writer getFileUTF8Writer(java.io.File file)

Create a new file writer that uses UTF-8.

Parameters:

file - A File to write to.

Returns:

A Writer for this file.

getFileUTF8AppendWriter

public static java.io.Writer getFileUTF8AppendWriter(java.io.File file)

Create a new appending file writer that uses UTF-8.

Parameters:

file - A File to append to.

Returns:

A Writer for this file.

makeTransformer

public static javax.xml.transform.Transformer makeTransformer(boolean declaration,
                                                              boolean indent)

Helper to make an XML Transformer.

Parameters:

declaration - If true, include the XML declaration.

indent - If true, set up the transformer to indent.

Returns:

A suitable Transformer.

deleteFile

public static void deleteFile(java.io.File file)

Delete a file.

Parameters:

file - The File to delete.

deleteFiles

public static void deleteFiles(java.util.List<java.io.File> files)

Delete a list of files.

Parameters:

files - The list of Files to delete.

fileAnySuffix

public static boolean fileAnySuffix(java.io.File file,
                                    java.lang.String... suffixes)

Does a readable file have a matching suffix?

Parameters:

file - The File to check.

suffixes - Suffixes to test.

Returns:

True if any suffix matches.

directoryAllPresent

public static boolean directoryAllPresent(java.io.File dir,
                                          java.lang.String... names)

Does a directory contain the given file/s?

Parameters:

dir - The directory File to check.

names - The name of the files to find therein.

Returns:

True if the file is present and readable.

delay

public static void delay(long ms,
                         java.lang.String warning)

Delay by a number of milliseconds.

Parameters:

ms - The number of milliseconds to delay.

warning - If non-null, log this warning message on interrupt, otherwise propagate the interrupt.

now

public static long now()

Current time since epoch in milliseconds.

Returns:

Time since epoch.

garbageCollect

public static void garbageCollect()

Run the garbage collector. Route all gc calls here, so we can disable the findbugs warning.

isHeadless

public static boolean isHeadless()

Are we in headless mode?

Returns:

True if in headless mode.

getGoodGraphicsDevice

public static java.awt.GraphicsDevice getGoodGraphicsDevice()

Get a good screen device for starting FreeCol.

Returns:

A screen device, or null if none available (as in headless mode).

determineDpi

public static int determineDpi(java.awt.GraphicsDevice gd)

Tries to determine the DPI of the given GraphicsDevice.

Parameters:

gd - The GraphicsDevice to determine the DPI for.

Returns:

The calculated DPI.