Utils

java.lang.Object
- org.omnifaces.util.Utils

```
public final class Utils
extends Object
```
Collection of general utility methods that do not fit in one of the more specific classes.

Author:

Arjan Tijms, Bauke Scholtz

Field Summary

Fields
Modifier and Type Field and Description

static Comparator<Comparable> NULL_COMPARATOR
This comparator also takes account with null values and sorts them first.

Fields
Modifier and Type	Field and Description
`static Comparator<Comparable>`	`NULL_COMPARATOR` This comparator also takes account with null values and sorts them first.

Method Summary

Methods
Modifier and Type	Method and Description
`static IOException`	`close(Closeable resource)` Check if the given resource is not `null` and then close it, whereby any caught `IOException` is been returned instead of thrown, so that the caller can if necessary handle (log) or just ignore it without the need to put another try-catch.
`static <T> T`	`coalesce(T... objects)` Returns the first non-`null` object of the argument list, or `null` if there is no such element.
`static boolean`	`containsByClassName(Collection<?> objects, String className)` Checks if the given collection contains an object with the given class name.
`static List<String>`	`csvToList(String values)` Converts comma separated values in a string into a list with those values.
`static List<String>`	`csvToList(String values, String delimiter)` Converts comma separated values in a string into a list with those values.
`static String`	`decodeURL(String string)` URL-decode the given string using UTF-8.
`static String`	`encodeURL(String string)` URL-encode the given string using UTF-8.
`static String`	`escapeJS(String string, boolean escapeSingleQuote)` Escapes the given string according the JavaScript code rules.
`static String`	`formatRFC1123(Date date)` Formats the given `Date` to a string in RFC1123 format.
`static boolean`	`isAnyEmpty(Object... values)` Returns `true` if at least one value is empty.
`static boolean`	`isBlank(String string)` Returns `true` if the given string is null or is empty or contains whitespace only.
`static boolean`	`isDecimal(String string)` Returns `true` if the given string is parseable as a decimal.
`static boolean`	`isEmpty(Collection<?> collection)` Returns `true` if the given collection is null or is empty.
`static boolean`	`isEmpty(Map<?,?> map)` Returns `true` if the given map is null or is empty.
`static boolean`	`isEmpty(Object value)` Returns `true` if the given value is null or is empty.
`static boolean`	`isEmpty(Object[] array)` Returns `true` if the given array is null or is empty.
`static boolean`	`isEmpty(String string)` Returns `true` if the given string is null or is empty.
`static boolean`	`isNumber(String string)` Returns `true` if the given string is parseable as a number.
`static <T> boolean`	`isOneOf(T object, T... objects)` Returns `true` if the given object equals one of the given objects.
`static <T> List<T>`	`iterableToList(Iterable<T> iterable)` Converts an iterable into a list.
`static <T extends Comparable<T>> TreeSet<T>`	`nullSafeTreeSet(Collection<T> collection)` Create a new `TreeSet` which uses `NULL_COMPARATOR`, add the given collection to it and return the `TreeSet`.
`static Date`	`parseRFC1123(String string)` Parses the given string in RFC1123 format to a `Date` object.
`static <T> Map<T,T>`	`reverse(Map<T,T> source)` Returns a new map that contains the reverse of the given map.
`static String`	`serializeURLSafe(String string)` Serialize the given string to the short possible unique URL-safe representation.
`static boolean`	`startsWithOneOf(String string, String... prefixes)` Returns `true` if the given string starts with one of the given prefixes.
`static long`	`stream(InputStream input, OutputStream output)` Stream the given input to the given output by NIO `ByteBuffer`.
`static <T> Set<T>`	`unmodifiableSet(Object... values)` Creates an unmodifiable set based on the given values.
`static String`	`unserializeURLSafe(String string)` Unserialize the given serialized URL-safe string.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - NULL_COMPARATOR
```
public static final Comparator<Comparable> NULL_COMPARATOR
```
    This comparator also takes account with null values and sorts them first.
    
    Since:
    
    1.7
- Method Detail
  - isEmpty
```
public static boolean isEmpty(String string)
```
    Returns true if the given string is null or is empty.
    
    Parameters:
    string - The string to be checked on emptiness.
    
    Returns:
    true if the given string is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Object[] array)
```
    Returns true if the given array is null or is empty.
    
    Parameters:
    array - The array to be checked on emptiness.
    
    Returns:
    true if the given array is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Collection<?> collection)
```
    Returns true if the given collection is null or is empty.
    
    Parameters:
    collection - The collection to be checked on emptiness.
    
    Returns:
    true if the given collection is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Map<?,?> map)
```
    Returns true if the given map is null or is empty.
    
    Parameters:
    map - The map to be checked on emptiness.
    
    Returns:
    true if the given map is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Object value)
```
    Returns true if the given value is null or is empty. Types of String, Collection, Map and Array are recognized. If none is recognized, then examine the emptiness of the toString() representation instead.
    
    Parameters:
    value - The value to be checked on emptiness.
    
    Returns:
    true if the given value is null or is empty.
  - isAnyEmpty
```
public static boolean isAnyEmpty(Object... values)
```
    Returns true if at least one value is empty.
    
    Parameters:
    values - the values to be checked on emptiness
    
    Returns:
    true if any value is empty and false if no values are empty
    Since:
    
    1.8
  - isBlank
```
public static boolean isBlank(String string)
```
    Returns true if the given string is null or is empty or contains whitespace only. In addition to isEmpty(String), this thus also returns true when string.trim().isEmpty() returns true.
    
    Parameters:
    string - The string to be checked on blankness.
    
    Returns:
    True if the given string is null or is empty or contains whitespace only.
    Since:
    
    1.5
  - isNumber
```
public static boolean isNumber(String string)
```
    Returns true if the given string is parseable as a number. I.e. it is not null, nor blank and contains solely digits. I.e., it won't throw a NumberFormatException when parsing as Long.
    
    Parameters:
    string - The string to be checked as number.
    
    Returns:
    true if the given string is parseable as a number.
    Since:
    
    1.5.
  - isDecimal
```
public static boolean isDecimal(String string)
```
    Returns true if the given string is parseable as a decimal. I.e. it is not null, nor blank and contains solely digits. I.e., it won't throw a NumberFormatException when parsing as Double.
    
    Parameters:
    string - The string to be checked as decimal.
    
    Returns:
    true if the given string is parseable as a decimal.
    Since:
    
    1.5.
  - coalesce
```
public static <T> T coalesce(T... objects)
```
    Returns the first non-null object of the argument list, or null if there is no such element.
    
    Type Parameters:
    T - The generic object type.
    Parameters:
    objects - The argument list of objects to be tested for non-null.
    
    Returns:
    The first non-null object of the argument list, or null if there is no such element.
  - isOneOf
```
public static <T> boolean isOneOf(T object,
                  T... objects)
```
    Returns true if the given object equals one of the given objects.
    
    Type Parameters:
    T - The generic object type.
    Parameters:
    object - The object to be checked if it equals one of the given objects.
    objects - The argument list of objects to be tested for equality.
    
    Returns:
    true if the given object equals one of the given objects.
  - startsWithOneOf
```
public static boolean startsWithOneOf(String string,
                      String... prefixes)
```
    Returns true if the given string starts with one of the given prefixes.
    
    Parameters:
    string - The object to be checked if it starts with one of the given prefixes.
    prefixes - The argument list of prefixes to be checked
    
    Returns:
    true if the given string starts with one of the given prefixes.
    Since:
    
    1.4
  - stream
```
public static long stream(InputStream input,
          OutputStream output)
                   throws IOException
```
    Stream the given input to the given output by NIO ByteBuffer. Both the input and output streams will implicitly be closed after streaming, regardless of whether an exception is been thrown or not.
    
    Parameters:
    input - The input stream.
    output - The output stream.
    
    Returns:
    The length of the written bytes.
    
    Throws:
    
    IOException - When an I/O error occurs.
  - close
```
public static IOException close(Closeable resource)
```
    Check if the given resource is not null and then close it, whereby any caught IOException is been returned instead of thrown, so that the caller can if necessary handle (log) or just ignore it without the need to put another try-catch.
    
    Parameters:
    resource - The closeable resource to be closed.
    
    Returns:
    The caught IOException, or null if none is been thrown.
  - unmodifiableSet
```
public static <T> Set<T> unmodifiableSet(Object... values)
```
    Creates an unmodifiable set based on the given values. If one of the values is an instance of an array or a collection, then each of its values will also be merged into the set. Nested arrays or collections will result in a ClassCastException.
    
    Parameters:
    values - The values to create an unmodifiable set for.
    
    Returns:
    An unmodifiable set based on the given values.
    
    Throws:
    
    ClassCastException - When one of the values or one of the arrays or collections is of wrong type.
    Since:
    
    1.1
  - iterableToList
```
public static <T> List<T> iterableToList(Iterable<T> iterable)
```
    Converts an iterable into a list.
    This method makes NO guarantee to whether changes to the source iterable are reflected in the returned list or not. For instance if the given iterable already is a list, it's returned directly.
    
    Parameters:
    iterable - The iterable to be converted.
    
    Returns:
    The list representation of the given iterable, possibly the same instance as that iterable.
    Since:
    
    1.5
  - csvToList
```
public static List<String> csvToList(String values)
```
    Converts comma separated values in a string into a list with those values.
    E.g. a string with "foo, bar, kaz" will be converted into a List with values:
    - "foo"
    - "bar"
    - "kaz"
    Note that whitespace will be stripped. Empty entries are not supported. This method defaults to using a comma (",") as delimiter. See csvToList(String, String) for when a different delimiter is needed.
    Parameters:
    values - string with comma separated values
    
    Returns:
    a list with all values encountered in the values argument, can be the empty list.
    Since:
    
    1.4
  - csvToList
```
public static List<String> csvToList(String values,
                     String delimiter)
```
    Converts comma separated values in a string into a list with those values.
    E.g. a string with "foo, bar, kaz" will be converted into a List with values:
    - "foo"
    - "bar"
    - "kaz"
    Note that whitespace will be stripped. Empty entries are not supported.
    Parameters:
    values - string with comma separated values
    delimiter - the delimiter used to separate the actual values in the values parameter.
    
    Returns:
    a list with all values encountered in the values argument, can be the empty list.
    Since:
    
    1.4
  - reverse
```
public static <T> Map<T,T> reverse(Map<T,T> source)
```
    Returns a new map that contains the reverse of the given map.
    The reverse of a map means that every value X becomes a key X' with as corresponding value Y' the key Y that was originally associated with the value X.
    
    Parameters:
    source - the map that is to be reversed
    
    Returns:
    the reverse of the given map
  - containsByClassName
```
public static boolean containsByClassName(Collection<?> objects,
                          String className)
```
    Checks if the given collection contains an object with the given class name.
    
    Parameters:
    objects - collection of objects to check
    className - name of the class to be checked for
    
    Returns:
    true if the collection contains at least one object with the given class name, false otherwise
    Since:
    
    1.6
  - nullSafeTreeSet
```
public static <T extends Comparable<T>> TreeSet<T> nullSafeTreeSet(Collection<T> collection)
```
    Create a new TreeSet which uses NULL_COMPARATOR, add the given collection to it and return the TreeSet.
    
    Since:
    
    1.7
  - formatRFC1123
```
public static String formatRFC1123(Date date)
```
    Formats the given Date to a string in RFC1123 format. This format is used in HTTP headers and in JavaScript Date constructor.
    
    Parameters:
    date - The Date to be formatted to a string in RFC1123 format.
    
    Returns:
    The formatted string.
    Since:
    
    1.2
  - parseRFC1123
```
public static Date parseRFC1123(String string)
                         throws ParseException
```
    Parses the given string in RFC1123 format to a Date object.
    
    Parameters:
    string - The string in RFC1123 format to be parsed to a Date object.
    
    Returns:
    The parsed Date.
    
    Throws:
    
    ParseException - When the given string is not in RFC1123 format.
    Since:
    
    1.2
  - serializeURLSafe
```
public static String serializeURLSafe(String string)
```
    Serialize the given string to the short possible unique URL-safe representation. The current implementation will decode the given string with UTF-8 and then compress it with ZLIB using "best compression" algorithm and then Base64-encode the resulting bytes whereafter the Base64 characters /, + and = are been replaced by respectively ~, - and _ to make it URL-safe (so that no platform-sensitive URL-encoding needs to be done when used in URLs).
    
    Parameters:
    string - The string to be serialized.
    
    Returns:
    The serialized URL-safe string, or null when the given string is itself null.
    Since:
    
    1.2
  - unserializeURLSafe
```
public static String unserializeURLSafe(String string)
```
    Unserialize the given serialized URL-safe string. This does the reverse of serializeURLSafe(String).
    
    Parameters:
    string - The serialized URL-safe string to be unserialized.
    
    Returns:
    The unserialized string, or null when the given string is by itself null.
    
    Throws:
    
    IllegalArgumentException - When the given serialized URL-safe string is not in valid format as returned by serializeURLSafe(String).
    Since:
    
    1.2
  - encodeURL
```
public static String encodeURL(String string)
```
    URL-encode the given string using UTF-8.
    
    Parameters:
    string - The string to be URL-encoded using UTF-8.
    
    Returns:
    The given string, URL-encoded using UTF-8, or null if null was given.
    
    Throws:
    
    UnsupportedOperationException - When UTF-8 is not supported.
    Since:
    
    1.4
  - decodeURL
```
public static String decodeURL(String string)
```
    URL-decode the given string using UTF-8.
    
    Parameters:
    string - The string to be URL-decode using UTF-8.
    
    Returns:
    The given string, URL-decode using UTF-8, or null if null was given.
    
    Throws:
    
    UnsupportedOperationException - When UTF-8 is not supported.
    Since:
    
    1.4
  - escapeJS
```
public static String escapeJS(String string,
              boolean escapeSingleQuote)
```
    Escapes the given string according the JavaScript code rules. This escapes among others the special characters, the whitespace, the quotes and the unicode characters. Useful whenever you want to use a Java string variable as a JavaScript string variable.
    
    Parameters:
    string - The string to be escaped according the JavaScript code rules.
    escapeSingleQuote - Whether to escape single quotes as well or not. Set to false if you want to escape it for usage in JSON.
    
    Returns:
    The escaped string according the JavaScript code rules.

Class Utils

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NULL_COMPARATOR

Method Detail

isEmpty

isEmpty

isEmpty

isEmpty

isEmpty

isAnyEmpty

isBlank

isNumber

isDecimal

coalesce

isOneOf

startsWithOneOf

stream

close

unmodifiableSet

iterableToList

csvToList

csvToList

reverse

containsByClassName

nullSafeTreeSet

formatRFC1123

parseRFC1123

serializeURLSafe

unserializeURLSafe

encodeURL

decodeURL

escapeJS