com.puppycrawl.tools.checkstyle.utils

Class CommonUtil

java.lang.Object

com.puppycrawl.tools.checkstyle.utils.CommonUtil

public final class CommonUtil
extends java.lang.Object

Contains utility methods.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CLASSPATH_URL_PROTOCOL Pseudo URL protocol for loading from the class path.
static int	DEFAULT_TAB_WIDTH Default tab width for column reporting.
static byte[]	EMPTY_BYTE_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
static double[]	EMPTY_DOUBLE_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
static int[]	EMPTY_INT_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
static java.lang.Integer[]	EMPTY_INTEGER_OBJECT_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
static java.lang.Object[]	EMPTY_OBJECT_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
static java.lang.String[]	EMPTY_STRING_ARRAY Copied from org.apache.commons.lang3.ArrayUtils.
private static java.lang.String	UNABLE_TO_FIND_EXCEPTION_PREFIX Prefix for the exception when unable to find resource.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	CommonUtil() Stop instances being created.

Method Summary

Modifier and Type	Method and Description
static java.lang.String	baseClassName(java.lang.String type) Returns base class name from qualified name.
static void	close(java.io.Closeable closeable) Closes a stream re-throwing IOException as IllegalStateException.
static java.util.regex.Pattern	createPattern(java.lang.String pattern) Helper method to create a regular expression.
static java.util.regex.Pattern	createPattern(java.lang.String pattern, int flags) Helper method to create a regular expression with a specific flags.
static boolean	endsWithChar(java.lang.String value, char suffix) Tests if this string ends with the specified suffix.
static java.lang.String	fillTemplateWithStringsByRegexp(java.lang.String template, java.lang.String lineToPlaceInTemplate, java.util.regex.Pattern regexp) Puts part of line, which matches regexp into given template on positions $n where 'n' is number of matched part in line.
static java.net.URL	getCheckstyleResource(java.lang.String name) Finds a resource with a given name in the Checkstyle resource bundle.
static <T> java.lang.reflect.Constructor<T>	getConstructor(java.lang.Class<T> targetClass, java.lang.Class<?>... parameterTypes) Gets constructor of targetClass.
static java.lang.String	getFileExtension(java.lang.String fileNameWithExtension) Returns file extension for the given file name or empty string if file does not have an extension.
static java.lang.String	getFileNameWithoutExtension(java.lang.String fullFilename) Returns file name without extension.
private static java.net.URI	getFilepathOrClasspathUri(java.lang.String filename) Resolves the specified local filename, possibly with 'classpath:' protocol, to a URI.
static java.net.URI	getResourceFromClassPath(java.lang.String filename) Gets a resource from the classpath.
static java.net.URI	getUriByFilename(java.lang.String filename) Resolve the specified filename to a URI.
static java.net.URI	getWebOrFileProtocolUri(java.lang.String filename) Resolves the specified filename containing 'http', 'https', 'ftp', and 'file' protocols (or any RFC 2396 compliant URL) to a URI.
static boolean	hasWhitespaceBefore(int index, java.lang.String line) Returns whether the specified string contains only whitespace up to the specified index.
static int	indexOfNonWhitespace(java.lang.String value) Method to find the index of the first non-whitespace character in a string.
static <T> T	invokeConstructor(java.lang.reflect.Constructor<T> constructor, java.lang.Object... parameters) Returns new instance of a class.
static boolean	isBlank(java.lang.String value) Checks if the value arg is blank by either being null, empty, or contains only whitespace characters.
static boolean	isCodePointWhitespace(int[] codePoints, int index) Converts the Unicode code point at index index to it's UTF-16 representation, then checks if the character is whitespace.
static boolean	isIdentifier(java.lang.String str) Checks whether the given string is a valid identifier.
static boolean	isInt(java.lang.String str) Checks whether the string contains an integer value.
static boolean	isName(java.lang.String str) Checks whether the given string is a valid name.
static boolean	isPatternValid(java.lang.String pattern) Validates whether passed string is a valid pattern or not.
static int	lengthExpandedTabs(java.lang.String inputString, int toIdx, int tabWidth) Returns the length of a String prefix with tabs expanded.
static int	lengthMinusTrailingWhitespace(java.lang.String line) Returns the length of a string ignoring all trailing whitespace.
static boolean	matchesFileExtension(java.io.File file, java.lang.String... fileExtensions) Returns whether the file extension matches what we are meant to process.
static java.lang.String	relativizeAndNormalizePath(java.lang.String baseDirectory, java.lang.String path) Constructs a normalized relative path between base directory and a given path.
static boolean	startsWithChar(java.lang.String value, char prefix) Tests if this string starts with the specified prefix.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_TAB_WIDTH

public static final int DEFAULT_TAB_WIDTH

Default tab width for column reporting.

See Also:

Constant Field Values

EMPTY_STRING_ARRAY

public static final java.lang.String[] EMPTY_STRING_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

EMPTY_INTEGER_OBJECT_ARRAY

public static final java.lang.Integer[] EMPTY_INTEGER_OBJECT_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

EMPTY_OBJECT_ARRAY

public static final java.lang.Object[] EMPTY_OBJECT_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

EMPTY_INT_ARRAY

public static final int[] EMPTY_INT_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

EMPTY_BYTE_ARRAY

public static final byte[] EMPTY_BYTE_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

EMPTY_DOUBLE_ARRAY

public static final double[] EMPTY_DOUBLE_ARRAY

Copied from org.apache.commons.lang3.ArrayUtils.

CLASSPATH_URL_PROTOCOL

public static final java.lang.String CLASSPATH_URL_PROTOCOL

Pseudo URL protocol for loading from the class path.

See Also:

Constant Field Values

UNABLE_TO_FIND_EXCEPTION_PREFIX

private static final java.lang.String UNABLE_TO_FIND_EXCEPTION_PREFIX

Prefix for the exception when unable to find resource.

See Also:

Constant Field Values

Constructor Detail

CommonUtil

private CommonUtil()

Stop instances being created.

Method Detail

createPattern

public static java.util.regex.Pattern createPattern(java.lang.String pattern)

Helper method to create a regular expression.

Parameters:

pattern - the pattern to match

Returns:

a created regexp object

Throws:

java.lang.IllegalArgumentException - if unable to create Pattern object.

createPattern

public static java.util.regex.Pattern createPattern(java.lang.String pattern,
                                                    int flags)

Helper method to create a regular expression with a specific flags.

Parameters:

pattern - the pattern to match

flags - the flags to set

Returns:

a created regexp object

Throws:

java.lang.IllegalArgumentException - if unable to create Pattern object.

matchesFileExtension

public static boolean matchesFileExtension(java.io.File file,
                                           java.lang.String... fileExtensions)

Returns whether the file extension matches what we are meant to process.

Parameters:

file - the file to be checked.

fileExtensions - files extensions, empty property in config makes it matches to all.

Returns:

whether there is a match.

hasWhitespaceBefore

public static boolean hasWhitespaceBefore(int index,
                                          java.lang.String line)

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

Parameters:

index - index to check up to

line - the line to check

Returns:

whether there is only whitespace

lengthMinusTrailingWhitespace

public static int lengthMinusTrailingWhitespace(java.lang.String line)

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:

line - the string to process

Returns:

the length of the string ignoring all trailing whitespace

lengthExpandedTabs

public static int lengthExpandedTabs(java.lang.String inputString,
                                     int toIdx,
                                     int tabWidth)

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:

inputString - the input String

toIdx - index in string (exclusive) where the calculation stops

tabWidth - the distance between tab stop position.

Returns:

the length of string.substring(0, toIdx) with tabs expanded.

isPatternValid

public static boolean isPatternValid(java.lang.String pattern)

Validates whether passed string is a valid pattern or not.

Parameters:

pattern - string to validate

Returns:

true if the pattern is valid false otherwise

baseClassName

public static java.lang.String baseClassName(java.lang.String type)

Returns base class name from qualified name.

Parameters:

type - the fully qualified name. Cannot be null

Returns:

the base class name from a fully qualified name

relativizeAndNormalizePath

public static java.lang.String relativizeAndNormalizePath(java.lang.String baseDirectory,
                                                          java.lang.String path)

Constructs a normalized relative path between base directory and a given path.

Parameters:

baseDirectory - the base path to which given path is relativized

path - the path to relativize against base directory

Returns:

the relative normalized path between base directory and path or path if base directory is null.

startsWithChar

public static boolean startsWithChar(java.lang.String value,
                                     char prefix)

Tests if this string starts with the specified prefix.

It is faster version of String.startsWith(String) optimized for one-character prefixes at the expense of some readability. Suggested by SimplifyStartsWith PMD rule: http://pmd.sourceforge.net/pmd-5.3.1/pmd-java/rules/java/optimizations.html#SimplifyStartsWith

Parameters:

value - the String to check

prefix - the prefix to find

Returns:

true if the char is a prefix of the given String; false otherwise.

endsWithChar

public static boolean endsWithChar(java.lang.String value,
                                   char suffix)

Tests if this string ends with the specified suffix.

It is faster version of String.endsWith(String) optimized for one-character suffixes at the expense of some readability. Suggested by SimplifyStartsWith PMD rule: http://pmd.sourceforge.net/pmd-5.3.1/pmd-java/rules/java/optimizations.html#SimplifyStartsWith

Parameters:

value - the String to check

suffix - the suffix to find

Returns:

true if the char is a suffix of the given String; false otherwise.

getConstructor

public static <T> java.lang.reflect.Constructor<T> getConstructor(java.lang.Class<T> targetClass,
                                                                  java.lang.Class<?>... parameterTypes)

Gets constructor of targetClass.

Type Parameters:

T - type of the target class object.

Parameters:

targetClass - from which constructor is returned

parameterTypes - of constructor

Returns:

constructor of targetClass

Throws:

java.lang.IllegalStateException - if any exception occurs

See Also:

Class.getConstructor(Class[])

invokeConstructor

public static <T> T invokeConstructor(java.lang.reflect.Constructor<T> constructor,
                                      java.lang.Object... parameters)

Returns new instance of a class.

Type Parameters:

T - type of constructor

Parameters:

constructor - to invoke

parameters - to pass to constructor

Returns:

new instance of class

Throws:

java.lang.IllegalStateException - if any exception occurs

See Also:

Constructor.newInstance(Object...)

close

public static void close(java.io.Closeable closeable)

Closes a stream re-throwing IOException as IllegalStateException.

Parameters:

closeable - Closeable object

Throws:

java.lang.IllegalStateException - when any IOException occurs

getUriByFilename

public static java.net.URI getUriByFilename(java.lang.String filename)
                                     throws CheckstyleException

Resolve the specified filename to a URI.

Parameters:

filename - name of the file

Returns:

resolved file URI

Throws:

CheckstyleException - on failure

getWebOrFileProtocolUri

public static java.net.URI getWebOrFileProtocolUri(java.lang.String filename)

Resolves the specified filename containing 'http', 'https', 'ftp', and 'file' protocols (or any RFC 2396 compliant URL) to a URI.

Parameters:

filename - name of the file

Returns:

resolved file URI or null if URL is malformed or non-existent

getFilepathOrClasspathUri

private static java.net.URI getFilepathOrClasspathUri(java.lang.String filename)
                                               throws CheckstyleException

Resolves the specified local filename, possibly with 'classpath:' protocol, to a URI. First we attempt to create a new file with given filename, then attempt to load file from class path.

Parameters:

filename - name of the file

Returns:

resolved file URI

Throws:

CheckstyleException - on failure

getResourceFromClassPath

public static java.net.URI getResourceFromClassPath(java.lang.String filename)
                                             throws CheckstyleException

Gets a resource from the classpath.

Parameters:

filename - name of file

Returns:

URI of file in classpath

Throws:

CheckstyleException - on failure

getCheckstyleResource

public static java.net.URL getCheckstyleResource(java.lang.String name)

Finds a resource with a given name in the Checkstyle resource bundle. This method is intended only for internal use in Checkstyle tests for easy mocking to gain 100% coverage.

Parameters:

name - name of the desired resource

Returns:

URI of the resource

fillTemplateWithStringsByRegexp

public static java.lang.String fillTemplateWithStringsByRegexp(java.lang.String template,
                                                               java.lang.String lineToPlaceInTemplate,
                                                               java.util.regex.Pattern regexp)

Puts part of line, which matches regexp into given template on positions $n where 'n' is number of matched part in line.

Parameters:

template - the string to expand.

lineToPlaceInTemplate - contains expression which should be placed into string.

regexp - expression to find in comment.

Returns:

the string, based on template filled with given lines

getFileNameWithoutExtension

public static java.lang.String getFileNameWithoutExtension(java.lang.String fullFilename)

Returns file name without extension. We do not use the method from Guava library to reduce Checkstyle's dependencies on external libraries.

Parameters:

fullFilename - file name with extension.

Returns:

file name without extension.

getFileExtension

public static java.lang.String getFileExtension(java.lang.String fileNameWithExtension)

Returns file extension for the given file name or empty string if file does not have an extension. We do not use the method from Guava library to reduce Checkstyle's dependencies on external libraries.

Parameters:

fileNameWithExtension - file name with extension.

Returns:

file extension for the given file name or empty string if file does not have an extension.

isIdentifier

public static boolean isIdentifier(java.lang.String str)

Checks whether the given string is a valid identifier.

Parameters:

str - A string to check.

Returns:

true when the given string contains valid identifier.

isName

public static boolean isName(java.lang.String str)

Checks whether the given string is a valid name.

Parameters:

str - A string to check.

Returns:

true when the given string contains valid name.

isBlank

public static boolean isBlank(java.lang.String value)

Checks if the value arg is blank by either being null, empty, or contains only whitespace characters.

Parameters:

value - A string to check.

Returns:

true if the arg is blank.

indexOfNonWhitespace

public static int indexOfNonWhitespace(java.lang.String value)

Method to find the index of the first non-whitespace character in a string.

Parameters:

value - the string to find the first index of a non-whitespace character for.

Returns:

the index of the first non-whitespace character.

isInt

public static boolean isInt(java.lang.String str)

Checks whether the string contains an integer value.

Parameters:

str - a string to check

Returns:

true if the given string is an integer, false otherwise.

isCodePointWhitespace

public static boolean isCodePointWhitespace(int[] codePoints,
                                            int index)

Converts the Unicode code point at index index to it's UTF-16 representation, then checks if the character is whitespace. Note that the given index index should correspond to the location of the character to check in the string, not in code points.

Parameters:

codePoints - the array of Unicode code points

index - the index of the character to check

Returns:

true if character at index is whitespace