CommonUtils (checkstyle 6.15 API)

java.lang.Object
- com.puppycrawl.tools.checkstyle.utils.CommonUtils

```
public final class CommonUtils
extends Object
```
Contains utility methods.

Author:

Aleksey Nesterenko

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`baseClassName(String type)`
`static void`	`close(Closeable closeable)` Closes a stream re-throwing IOException as IllegalStateException.
`static Pattern`	`createPattern(String pattern)` Helper method to create a regular expression.
`static Pattern`	`createPattern(String pattern, int flags)` Helper method to create a regular expression with a specific flags.
`static boolean`	`endsWithChar(String value, char suffix)` Tests if this string ends with the specified suffix.
`static String`	`fillTemplateWithStringsByRegexp(String template, String lineToPlaceInTemplate, 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 <T> Constructor<T>`	`getConstructor(Class<T> targetClass, Class<?>... parameterTypes)` Gets constructor of targetClass.
`static URI`	`getUriByFilename(String filename)` Resolve the specified filename to a URI.
`static boolean`	`hasWhitespaceBefore(int index, String line)` Returns whether the specified string contains only whitespace up to the specified index.
`static <T> T`	`invokeConstructor(Constructor<T> constructor, Object... parameters)`
`static boolean`	`isPatternValid(String pattern)` Validates whether passed string is a valid pattern or not.
`static int`	`lengthExpandedTabs(String inputString, int toIdx, int tabWidth)` Returns the length of a String prefix with tabs expanded.
`static int`	`lengthMinusTrailingWhitespace(String line)` Returns the length of a string ignoring all trailing whitespace.
`static boolean`	`matchesFileExtension(File file, String... fileExtensions)` Returns whether the file extension matches what we are meant to process.
`static String`	`relativizeAndNormalizePath(String baseDirectory, String path)` Constructs a normalized relative path between base directory and a given path.
`static boolean`	`startsWithChar(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

- Method Detail
  - createPattern
```
public static Pattern createPattern(String pattern)
```
    Helper method to create a regular expression.
    
    Parameters:
    
    pattern - the pattern to match
    
    Returns:
    
    a created regexp object
    
    Throws:
    
    org.apache.commons.beanutils.ConversionException - if unable to create Pattern object.
  - createPattern
```
public static Pattern createPattern(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:
    
    org.apache.commons.beanutils.ConversionException - if unable to create Pattern object.
  - matchesFileExtension
```
public static boolean matchesFileExtension(File file,
                                           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,
                                          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(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(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(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 String baseClassName(String type)
```
    Parameters:
    
    type - the fully qualified name. Cannot be null
    
    Returns:
    
    the base class name from a fully qualified name
  - relativizeAndNormalizePath
```
public static String relativizeAndNormalizePath(String baseDirectory,
                                                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(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(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> Constructor<T> getConstructor(Class<T> targetClass,
                                                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 or IllegalStateException if any exception occurs
    
    See Also:
    
    Class.getConstructor(Class[])
  - invokeConstructor
```
public static <T> T invokeConstructor(Constructor<T> constructor,
                                      Object... parameters)
```
    Type Parameters:
    
    T - type of constructor
    
    Parameters:
    
    constructor - to invoke
    
    parameters - to pass to constructor
    
    Returns:
    
    new instance of class or IllegalStateException if any exception occurs
    
    See Also:
    
    Constructor.newInstance(Object...)
  - close
```
public static void close(Closeable closeable)
```
    Closes a stream re-throwing IOException as IllegalStateException.
    
    Parameters:
    
    closeable - Closeable object
  - getUriByFilename
```
public static URI getUriByFilename(String filename)
                            throws CheckstyleException
```
    Resolve the specified filename to a URI.
    
    Parameters:
    
    filename - name os the file
    
    Returns:
    
    resolved header file URI
    
    Throws:
    
    CheckstyleException - on failure
  - fillTemplateWithStringsByRegexp
```
public static String fillTemplateWithStringsByRegexp(String template,
                                                     String lineToPlaceInTemplate,
                                                     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

Class CommonUtils

Method Summary

Methods inherited from class java.lang.Object

Method Detail

createPattern

createPattern

matchesFileExtension

hasWhitespaceBefore

lengthMinusTrailingWhitespace

lengthExpandedTabs

isPatternValid

baseClassName

relativizeAndNormalizePath

startsWithChar

endsWithChar

getConstructor

invokeConstructor

close

getUriByFilename

fillTemplateWithStringsByRegexp