com.puppycrawl.tools.checkstyle.api

Class Utils

public final class Utils extends Object

Contains utility methods.

Version: 1.0

Author: Oliver Burn

Method Summary
static String	baseClassname(String aType)
static Pattern	createPattern(String aPattern) Helper method to create a regular expression.
static File[]	filterFilesByExtension(File[] aFiles, String[] aFileExtensions) Filter a set of files by their extension.
static Log	getExceptionLogger() Accessor for shared instance of logger which should be used to log all exceptions occured during `FileSetCheck` work (`debug()` should be used).
static String[]	getLines(String aFileName) Loads the contents of a file in a String array.
static String[]	getLines(String aFileName, String aCharsetName) Loads the contents of a file in a String array using the named charset.
static Pattern	getPattern(String aPattern) This is a factory method to return an Pattern object for the specified regular expression.
static Pattern	getPattern(String aPattern, int aCompileFlags) This is a factory method to return an Pattern object for the specified regular expression and compile flags.
static String	getStrippedFileName(String aBasedir, String aFileName) Create a stripped down version of a filename.
static int	lengthExpandedTabs(String aString, int aToIdx, int aTabWidth) Returns the length of a String prefix with tabs expanded.
static int	lengthMinusTrailingWhitespace(String aLine) Returns the length of a string ignoring all trailing whitespace.
static boolean	whitespaceBefore(int aIndex, String aLine) Returns whether the specified string contains only whitespace up to the specified index.

Method Detail

baseClassname

public static String baseClassname(String aType)

Parameters: aType the fully qualified name. Cannot be null

Returns: the base class name from a fully qualified name

createPattern

public static Pattern createPattern(String aPattern)

Helper method to create a regular expression.

Parameters: aPattern the pattern to match

Returns: a created regexp object

Throws: ConversionException if unable to create Pattern object.

filterFilesByExtension

public static File[] filterFilesByExtension(File[] aFiles, String[] aFileExtensions)

Filter a set of files by their extension.

Parameters: aFiles a set of files aFileExtensions a set of file extension, like ".txt" or ".java"

Returns: aFiles if aFileExtensions is null or empty, the subset of aFiles that have extensions in aFileExtensions otherwise

getExceptionLogger

public static Log getExceptionLogger()

Accessor for shared instance of logger which should be used to log all exceptions occured during FileSetCheck work (debug() should be used).

Returns: shared exception logger.

getLines

public static String[] getLines(String aFileName)

Loads the contents of a file in a String array.

Parameters: aFileName the name of the file to load

Returns: the lines in the file

Throws: IOException error occurred

getLines

public static String[] getLines(String aFileName, String aCharsetName)

Loads the contents of a file in a String array using the named charset.

Parameters: aFileName the name of the file to load aCharsetName the name of a supported charset

Returns: the lines in the file

Throws: IOException error occurred

getPattern

public static Pattern getPattern(String aPattern)

This is a factory method to return an Pattern object for the specified regular expression. It calls Utils with the compile flags defaults to 0.

Parameters: aPattern the regular expression pattern

Returns: an Pattern object for the supplied pattern

Throws: PatternSyntaxException an invalid pattern was supplied

getPattern

public static Pattern getPattern(String aPattern, int aCompileFlags)

This is a factory method to return an Pattern object for the specified regular expression and compile flags.

This method is not MT safe, but neither are the returned Pattern objects.

Parameters: aPattern the regular expression pattern aCompileFlags the compilation flags

Returns: an Pattern object for the supplied pattern

Throws: PatternSyntaxException an invalid pattern was supplied

getStrippedFileName

public static String getStrippedFileName(String aBasedir, String aFileName)

Create a stripped down version of a filename.

Parameters: aBasedir the prefix to strip off the original filename aFileName the original filename

Returns: the filename where an initial prefix of basedir is stripped

lengthExpandedTabs

public static int lengthExpandedTabs(String aString, int aToIdx, int aTabWidth)

Returns the length of a String prefix with tabs expanded. Each tab is counted as the number of characters is takes to jump to the next tab stop.

Parameters: aString the input String aToIdx index in aString (exclusive) where the calculation stops aTabWidth the distance betweeen tab stop position.

Returns: the length of aString.substring(0, aToIdx) with tabs expanded.

lengthMinusTrailingWhitespace

public static int lengthMinusTrailingWhitespace(String aLine)

Returns the length of a string ignoring all trailing whitespace. It is a pity that there is not a trim() like method that only removed the trailing whitespace.

Parameters: aLine the string to process

Returns: the length of the string ignoring all trailing whitespace

whitespaceBefore

public static boolean whitespaceBefore(int aIndex, String aLine)

Returns whether the specified string contains only whitespace up to the specified index.

Parameters: aIndex index to check up to aLine the line to check

Returns: whether there is only whitespace