Package org.apache.cayenne.util

## Class Util

- java.lang.Object
- - org.apache.cayenne.util.Util

-     public class Util
      extends Object

  Contains various unorganized static utility methods used across Cayenne.

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `Util()` |

  - ### Method Summary

    All Methods Static Methods Concrete Methods Deprecated Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `static String` | `capitalized​(String name)` | Capitalizes the first letter of the property name.
    `static <T extends Serializable> T` | `cloneViaSerialization​(T object)` | Creates Serializable object copy using serialization/deserialization.
    `static int` | `countMatches​(String str, String sub)` | Returns how many times the sub appears in the str.
    `static XMLReader` | `createXmlReader()` | Creates an XMLReader with default feature set.
    `static String` | `encodeXmlAttribute​(String string)` | Encodes a string so that it can be used as an attribute value in an XML document.
    `static String` | `extractFileExtension​(String fileName)` | Extracts extension from the file name.
    `static Class<?>` | `getJavaClass​(String className)` | Deprecated. since 4.0 this method based on statically defined class loading algorithm is not going to work in environments like OSGi.
    `static String` | `getPackagePath​(String className)` | Returns package name for the Java class as a path separated with forward slash ("/").
    `static int` | `hashCode​(Collection<?> c)` | Builds a hashCode of Collection.
    `static boolean` | `isAccessible​(Member member)` | Returns true if a Member is accessible via reflection under normal Java access controls.
    `static boolean` | `isBlank​(CharSequence cs)` | Returns true, if string not empty and contains non-whitespace characters.
    `static boolean` | `isEmptyString​(CharSequence string)` | Returns true, if the String is null or an empty string.
    `static boolean` | `isNumeric​(CharSequence cs)` |
    `static String` | `join​(Iterable<?> objects, String separator)` |
    `static <T> int` | `nullSafeCompare​(boolean nullsFirst, Comparable<T> o1, T o2)` | Compares two objects similar to "Comparable.compareTo(Object)".
    `static boolean` | `nullSafeEquals​(Object o1, Object o2)` | Compares two objects similar to "Object.equals(Object)".
    `static String` | `prettyTrim​(String str, int maxLength)` | Trims long strings substituting middle part with "...".
    `static Document` | `readDocument​(URL url)` |
    `static <T> Iterator<T>` | `sortedIterator​(Iterator<T> it, Comparator<T> comparator)` | Returns a sorted iterator from an unsorted one.
    `static String` | `specialCharsToJava​(String string)` | Replaces special chars with human-readable and Java-id-compatible symbols.
    `static Pattern` | `sqlPatternToPattern​(String pattern, boolean ignoreCase)` |
    `static String` | `stringFromFile​(File file)` | Reads file contents, returning it as a String, using System default line separator.
    `static String` | `stringFromFile​(File file, String joinWith)` | Reads file contents, returning it as a String, joining lines with provided separator.
    `static String` | `stripFileExtension​(String fileName)` | Strips extension from the file name.
    `static String` | `stripLineBreaks​(String string, char replaceWith)` | Strips "\n", "\r\n", "\r" from the argument string, replacing them with a provided character.
    `static String` | `stripPackageName​(String className)` | Returns an unqualified class name for the fully qualified name.
    `static String` | `substBackslashes​(String string)` | Replaces all backslashes "\" with forward slashes "/".
    `static File` | `toFile​(URL url)` | Converts URL to file.
    `static <K,​V> Map<K,​V>` | `toMap​(K[] keys, V[] values)` | Creates a mutable map out of two arrays with keys and values.
    `static String` | `uncapitalized​(String aString)` | Returns string with lowercased first letter
    `static String` | `underscoredToJava​(String name, boolean capitalize)` | Converts names like "ABCD_EFG_123" to Java-style names like "abcdEfg123".
    `static Throwable` | `unwindException​(Throwable th)` | Looks up and returns the root cause of an exception.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### Util

          public Util()

  - ### Method Detail

    - #### toFile

          public static File toFile​(URL url)
                             throws IllegalArgumentException

      Converts URL to file. Throws `IllegalArgumentException` if the URL is not a "file://" URL.
      Throws:
        `IllegalArgumentException`

    - #### stringFromFile

          public static String stringFromFile​(File file)
                                       throws IOException

      Reads file contents, returning it as a String, using System default line separator.
      Throws:
        `IOException`

    - #### stringFromFile

          public static String stringFromFile​(File file,
                                              String joinWith)
                                       throws IOException

      Reads file contents, returning it as a String, joining lines with provided separator.
      Throws:
        `IOException`

    - #### join

          public static String join​(Iterable<?> objects,
                                    String separator)

      Parameters:
        `objects` - An Iterable of objects that will be converted to Strings and joined together.
        `separator` - The separator between the strings.
      Returns:
        A single string of all the input strings separated by the separator.

    - #### substBackslashes

          public static String substBackslashes​(String string)

      Replaces all backslashes "\" with forward slashes "/". Convenience method to convert path Strings to URI format.

    - #### unwindException

          public static Throwable unwindException​(Throwable th)

      Looks up and returns the root cause of an exception. If none is found, returns supplied Throwable object unchanged. If root is found, recursively "unwraps" it, and returns the result to the user.

    - #### nullSafeEquals

          public static boolean nullSafeEquals​(Object o1,
                                               Object o2)

      Compares two objects similar to "Object.equals(Object)". Unlike Object.equals(..), this method doesn't throw an exception if any of the two objects is null.

    - #### nullSafeCompare

          public static <T> int nullSafeCompare​(boolean nullsFirst,
                                                Comparable<T> o1,
                                                T o2)

      Compares two objects similar to "Comparable.compareTo(Object)". Unlike Comparable.compareTo(..), this method doesn't throw an exception if any of the two objects is null.
      Since:
        1.1

    - #### isEmptyString

          public static boolean isEmptyString​(CharSequence string)

      Returns true, if the String is null or an empty string.

    - #### isBlank

          public static boolean isBlank​(CharSequence cs)

      Returns true, if string not empty and contains non-whitespace characters.
      Since:
        4.1

    - #### isNumeric

          public static boolean isNumeric​(CharSequence cs)

      Since:
        4.1

    - #### countMatches

          public static int countMatches​(String str,
                                         String sub)

      Returns how many times the sub appears in the str.
      Since:
        4.1

    - #### capitalized

          public static String capitalized​(String name)

      Capitalizes the first letter of the property name.
      Since:
        4.1

    - #### uncapitalized

          public static String uncapitalized​(String aString)

      Returns string with lowercased first letter
      Since:
        4.2

    - #### cloneViaSerialization

          public static <T extends Serializable> T cloneViaSerialization​(T object)
                                                                  throws Exception

      Creates Serializable object copy using serialization/deserialization.
      Throws:
        `Exception`

    - #### createXmlReader

          public static XMLReader createXmlReader()
                                           throws SAXException,
                                                  ParserConfigurationException

      Creates an XMLReader with default feature set. Note that all Cayenne internal XML parsers should probably use XMLReader obtained via this method for consistency sake, and can customize feature sets as needed.
      Throws:
        `SAXException`
        `ParserConfigurationException`

    - #### readDocument

          public static Document readDocument​(URL url)

      Parameters:
        `url` - to read
      Returns:
        org.w3c.dom.Document from the given URL
      Since:
        4.1

    - #### getPackagePath

          public static String getPackagePath​(String className)

      Returns package name for the Java class as a path separated with forward slash ("/"). Method is used to lookup resources that are located in package subdirectories. For example, a String "a/b/c" will be returned for class name "a.b.c.ClassName".

    - #### stripPackageName

          public static String stripPackageName​(String className)

      Returns an unqualified class name for the fully qualified name.
      Since:
        3.0

    - #### toMap

          public static <K,​V> Map<K,​V> toMap​(K[] keys,
                                                         V[] values)

      Creates a mutable map out of two arrays with keys and values.
      Since:
        1.2

    - #### extractFileExtension

          public static String extractFileExtension​(String fileName)

      Extracts extension from the file name. Dot is not included in the returned string.

    - #### stripFileExtension

          public static String stripFileExtension​(String fileName)

      Strips extension from the file name.

    - #### stripLineBreaks

          public static String stripLineBreaks​(String string,
                                               char replaceWith)

      Strips "\n", "\r\n", "\r" from the argument string, replacing them with a provided character.
      Since:
        3.1

    - #### encodeXmlAttribute

          public static String encodeXmlAttribute​(String string)

      Encodes a string so that it can be used as an attribute value in an XML document. Will do conversion of the greater/less signs, quotes and ampersands.

    - #### prettyTrim

          public static String prettyTrim​(String str,
                                          int maxLength)

      Trims long strings substituting middle part with "...".
      Parameters:
        `str` - String to trim.
        `maxLength` - maximum allowable length. Must be at least 5, or an IllegalArgumentException is thrown.
      Returns:
        String

    - #### sortedIterator

          public static <T> Iterator<T> sortedIterator​(Iterator<T> it,
                                                       Comparator<T> comparator)

      Returns a sorted iterator from an unsorted one. Use this method as a last resort, since it is much less efficient then just sorting a collection that backs the original iterator.

    - #### hashCode

          public static int hashCode​(Collection<?> c)

      Builds a hashCode of Collection.

    - #### sqlPatternToPattern

          public static Pattern sqlPatternToPattern​(String pattern,
                                                    boolean ignoreCase)

      Since:
        1.2

    - #### isAccessible

          public static boolean isAccessible​(Member member)

      Returns true if a Member is accessible via reflection under normal Java access controls.
      Since:
        1.2

    - #### getJavaClass

          @Deprecated
          public static Class<?> getJavaClass​(String className)
                                       throws ClassNotFoundException

      Deprecated.
      since 4.0 this method based on statically defined class loading algorithm is not going to work in environments like OSGi. `AdhocObjectFactory` should be used as it can provide the environment-specific class loading policy.
      Creates a Java class, handling regular class names as well as single-dimensional arrays and primitive types.
      Throws:
        `ClassNotFoundException`
      Since:
        1.2

    - #### underscoredToJava

          public static String underscoredToJava​(String name,
                                                 boolean capitalize)

      Converts names like "ABCD_EFG_123" to Java-style names like "abcdEfg123". If `capitalize` is true, returned name is capitalized (for instance if this is a class name).
      Since:
        4.0

    - #### specialCharsToJava

          public static String specialCharsToJava​(String string)

      Replaces special chars with human-readable and Java-id-compatible symbols.
      Since:
        4.0