Utils (OmniFaces 2.2 API)

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.
This class is not listed in showcase! Should I use it?

This class is indeed intented for internal usage only. We won't add methods here on user request. We only add methods here once we encounter non-DRY code in OmniFaces codebase. The methods may be renamed/changed without notice.
We don't stop you from using it if you think you find it useful, but you'd really better pick e.g. Google Guava or perhaps the good 'ol Apache Commons. This Utils class exists because OmniFaces intends to be free of 3rd party dependencies.

Author:

Arjan Tijms, Bauke Scholtz

Method Summary

All Methods Static Methods Concrete 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 boolean`	`isOneAnnotationPresent(Class<?> cls, Class<? extends Annotation>... annotations)` Returns `true` if the given class has at least one of the given annotations.
`static boolean`	`isOneInstanceOf(Class<?> cls, Class<?>... classes)` Returns `true` if an instance of the given class could also be an instance of one of the given classes.
`static <T> boolean`	`isOneOf(T object, T... objects)` Returns `true` if the given object equals one of the given objects.
`static <E> List<E>`	`iterableToList(Iterable<E> iterable)` Converts an iterable into a list.
`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(File file, OutputStream output, long start, long length)` Stream a specified range of the given file to the given output via NIO `Channels` and a directly allocated NIO `ByteBuffer`.
`static long`	`stream(InputStream input, OutputStream output)` Stream the given input to the given output via NIO `Channels` and a directly allocated NIO `ByteBuffer`.
`static byte[]`	`toByteArray(InputStream input)` Read the given input stream into a byte array.
`static <E> Set<E>`	`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

- 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
```
@SafeVarargs
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
```
@SafeVarargs
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
  - isOneInstanceOf
```
public static boolean isOneInstanceOf(Class<?> cls,
                                      Class<?>... classes)
```
    Returns true if an instance of the given class could also be an instance of one of the given classes.
    
    Parameters:
    
    cls - The class to be checked if it could also be an instance of one of the given classes.
    
    classes - The argument list of classes to be tested.
    
    Returns:
    
    true if the given class could also be an instance of one of the given classes.
    
    Since:
    
    2.0
  - isOneAnnotationPresent
```
@SafeVarargs
public static boolean isOneAnnotationPresent(Class<?> cls,
                                                          Class<? extends Annotation>... annotations)
```
    Returns true if the given class has at least one of the given annotations.
    
    Parameters:
    
    cls - The class to be checked if it has at least one of the given annotations.
    
    annotations - The argument list of annotations to be tested on the given class.
    
    Returns:
    
    true if the given clazz would be an instance of one of the given clazzes.
    
    Since:
    
    2.0
  - stream
```
public static long stream(InputStream input,
                          OutputStream output)
                   throws IOException
```
    Stream the given input to the given output via NIO Channels and a directly allocated 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.
  - stream
```
public static long stream(File file,
                          OutputStream output,
                          long start,
                          long length)
                   throws IOException
```
    Stream a specified range of the given file to the given output via NIO Channels and a directly allocated NIO ByteBuffer. The output stream will only implicitly be closed after streaming when the specified range represents the whole file, regardless of whether an exception is been thrown or not.
    
    Parameters:
    
    file - The file.
    
    output - The output stream.
    
    start - The start position (offset).
    
    length - The (intented) length of written bytes.
    
    Returns:
    
    The (actual) length of the written bytes. This may be smaller when the given length is too large.
    
    Throws:
    
    IOException - When an I/O error occurs.
    
    Since:
    
    2.2
  - toByteArray
```
public static byte[] toByteArray(InputStream input)
                          throws IOException
```
    Read the given input stream into a byte array. The given input stream will implicitly be closed after streaming, regardless of whether an exception is been thrown or not.
    
    Parameters:
    
    input - The input stream.
    
    Returns:
    
    The input stream as a byte array.
    
    Throws:
    
    IOException - When an I/O error occurs.
    
    Since:
    
    2.0
  - 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 <E> Set<E> 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.
    
    Type Parameters:
    
    E - The expected set element type.
    
    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 <E> List<E> iterableToList(Iterable<E> 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.
    
    Type Parameters:
    
    E - The generic iterable element type.
    
    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.
    
    Type Parameters:
    
    T - The generic map key/value type.
    
    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
  - 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 without the = padding, 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 inverse 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 this platform does not support UTF-8.
    
    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 this platform does not support UTF-8.
    
    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

This class is not listed in showcase! Should I use it?

Method Summary

Methods inherited from class java.lang.Object

Method Detail

isEmpty

isEmpty

isEmpty

isEmpty

isEmpty

isAnyEmpty

isBlank

isNumber

isDecimal

coalesce

isOneOf

startsWithOneOf

isOneInstanceOf

isOneAnnotationPresent

stream

stream

toByteArray

close

unmodifiableSet

iterableToList

csvToList

csvToList

reverse

containsByClassName

formatRFC1123

parseRFC1123

serializeURLSafe

unserializeURLSafe

encodeURL

decodeURL

escapeJS