org.apache.sshd.common.util

Class GenericUtils

java.lang.Object

org.apache.sshd.common.util.GenericUtils

public final class GenericUtils
extends Object

Author:

Apache MINA SSHD Project

Field Summary

Fields

Modifier and Type	Field and Description
static Comparator<String>	CASE_SENSITIVE_ORDER The complement of String.CASE_INSENSITIVE_ORDER
static boolean[]	EMPTY_BOOLEAN_ARRAY
static byte[]	EMPTY_BYTE_ARRAY
static char[]	EMPTY_CHAR_ARRAY
static Object[]	EMPTY_OBJECT_ARRAY
static String[]	EMPTY_STRING_ARRAY
static Object	NULL A value indicating a null value - to be used as a placeholder where nulls are not allowed
static String	QUOTES

Method Summary

Modifier and Type	Method and Description
static <T> List<T>	asList(T... values)
static <T> Set<T>	asSet(T... values)
static <V extends Comparable<V>> NavigableSet<V>	asSortedSet(Collection<? extends V> values)
static <V> NavigableSet<V>	asSortedSet(Comparator<? super V> comp, Collection<? extends V> values)
static <V> NavigableSet<V>	asSortedSet(Comparator<? super V> comp, V... values)
static <V extends Comparable<V>> NavigableSet<V>	asSortedSet(V... values)
static int	compare(char[] c1, char[] c2) Compares 2 character arrays - Note: null and empty are considered equal
static <T> boolean	containsAny(Collection<? extends T> coll, Iterable<? extends T> values)
static <B,D extends B> Function<D,B>	downcast()
static <T> boolean	equals(Collection<T> c1, Collection<T> c2)
static <T> int	findFirstDifferentValueIndex(Iterable<? extends T> c1, Iterable<? extends T> c2)
static <T> int	findFirstDifferentValueIndex(Iterable<? extends T> c1, Iterable<? extends T> c2, UnaryEquator<? super T> equator)
static <T> int	findFirstDifferentValueIndex(Iterator<? extends T> i1, Iterator<? extends T> i2)
static <T> int	findFirstDifferentValueIndex(Iterator<? extends T> i1, Iterator<? extends T> i2, UnaryEquator<? super T> equator)
static <T> int	findFirstDifferentValueIndex(List<? extends T> c1, List<? extends T> c2)
static <T> int	findFirstDifferentValueIndex(List<? extends T> c1, List<? extends T> c2, UnaryEquator<? super T> equator)
static <T> T	findFirstMatchingMember(Predicate<? super T> acceptor, Collection<? extends T> values)
static <T> T	findFirstMatchingMember(Predicate<? super T> acceptor, T... values)
static <T> void	forEach(Iterable<? extends T> values, Consumer<? super T> consumer)
static int	hashCode(String s)
static int	hashCode(String s, Boolean useUppercase)
static <T> T	head(Iterable<? extends T> it) Returns the first element in iterable - it has some optimization for List-s Deque-s and SortedSets.
static int	indexOf(CharSequence cs, char c)
static boolean	isEmpty(char[] chars)
static boolean	isEmpty(CharSequence cs)
static boolean	isEmpty(Collection<?> c)
static <T> boolean	isEmpty(Iterable<? extends T> iter)
static <T> boolean	isEmpty(Iterator<? extends T> iter)
static <T> boolean	isEmpty(T[] a)
static boolean	isNegativeOrNull(Duration d) Check if a duration is negative or zero
static boolean	isNotEmpty(CharSequence cs)
static boolean	isNotEmpty(Collection<?> c)
static <T> boolean	isNotEmpty(Iterable<? extends T> iter)
static <T> boolean	isNotEmpty(Iterator<? extends T> iter)
static boolean	isPositive(Duration d) Check if a duration is positive
static <T> Iterator<T>	iteratorOf(Iterable<T> iterable) Resolves to an always non-null iterator
static <T> Iterator<T>	iteratorOf(Iterator<T> iter) Resolves to an always non-null iterator
static String	join(Iterable<?> iter, char ch)
static String	join(Iterable<?> iter, CharSequence sep)
static String	join(Iterator<?> iter, char ch)
static String	join(Iterator<?> iter, CharSequence sep)
static <T> String	join(T[] values, char ch)
static <T> String	join(T[] values, CharSequence sep)
static int	lastIndexOf(CharSequence cs, char c)
static int	length(char[] chars)
static int	length(CharSequence cs)
static <T> int	length(T... a)
static <T,U> List<U>	map(Collection<? extends T> values, Function<? super T,? extends U> mapper)
static <T,U> NavigableSet<U>	mapSort(Collection<? extends T> values, Function<? super T,? extends U> mapper, Comparator<? super U> comparator)
static <T> Supplier<T>	memoizeLock(Supplier<? extends T> delegate) The delegate Suppliers get() method is called exactly once and the result is cached.
static <T> Iterable<T>	multiIterableSuppliers(Iterable<? extends Supplier<? extends Iterable<? extends T>>> providers) Wraps a group of Suppliers of Iterable instances into a "unified" Iterable of their values, in the same order as the suppliers - i.e., once the values from a specific supplier are exhausted, the next one is consulted, and so on, until all suppliers have been consulted
static <E extends Enum<E>> Set<E>	of(Collection<? extends E> values)
static <E extends Enum<E>> Set<E>	of(E... values)
static String	replace(String text, String repl, String with, int max) Replace a String with another String inside a larger String, for the first max values of the search String.
static String	replaceWhitespaceAndTrim(String s)
static int	safeCompare(String s1, String s2, boolean caseSensitive)
static <T> List<T>	selectMatchingMembers(Predicate<? super T> acceptor, Collection<? extends T> values) Returns a list of all the values that were accepted by a predicate
static <T> List<T>	selectMatchingMembers(Predicate<? super T> acceptor, T... values) Returns a list of all the values that were accepted by a predicate
static <T> T	selectNextMatchingValue(Iterator<?> values, Class<T> type)
static int	size(Collection<?> c)
static String[]	split(String s, char ch)
static <T> Stream<T>	stream(Iterable<T> values)
static CharSequence	stripDelimiters(CharSequence s, char delim)
static CharSequence	stripQuotes(CharSequence s)
static <T> Supplier<T>	supplierOf(T value) Wraps a value into a Supplier
static <T> Collector<T,?,NavigableSet<T>>	toSortedSet(Comparator<? super T> comparator)
static String	trimToEmpty(String s)
static <T> List<T>	unmodifiableList(Collection<? extends T> values)
static <T> List<T>	unmodifiableList(Stream<T> values)
static <T> List<T>	unmodifiableList(T... values)
static <U,V> Iterable<V>	wrapIterable(Iterable<? extends U> iter, Function<? super U,? extends V> mapper)
static <U,V> Iterator<V>	wrapIterator(Iterable<? extends U> iter, Function<? super U,? extends V> mapper)
static <U,V> Iterator<V>	wrapIterator(Iterator<? extends U> iter, Function<? super U,? extends V> mapper)

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_BYTE_ARRAY

public static final byte[] EMPTY_BYTE_ARRAY

EMPTY_CHAR_ARRAY

public static final char[] EMPTY_CHAR_ARRAY

EMPTY_STRING_ARRAY

public static final String[] EMPTY_STRING_ARRAY

EMPTY_OBJECT_ARRAY

public static final Object[] EMPTY_OBJECT_ARRAY

EMPTY_BOOLEAN_ARRAY

public static final boolean[] EMPTY_BOOLEAN_ARRAY

NULL

public static final Object NULL

A value indicating a null value - to be used as a placeholder where nulls are not allowed

CASE_SENSITIVE_ORDER

public static final Comparator<String> CASE_SENSITIVE_ORDER

The complement of String.CASE_INSENSITIVE_ORDER

QUOTES

public static final String QUOTES

See Also:

Constant Field Values

Method Detail

trimToEmpty

public static String trimToEmpty(String s)

replaceWhitespaceAndTrim

public static String replaceWhitespaceAndTrim(String s)

replace

public static String replace(String text,
                             String repl,
                             String with,
                             int max)

Replace a String with another String inside a larger String, for the first max values of the search String.

A null reference passed to this method is a no-op.

Parameters:

text - text to search and replace in

repl - String to search for

with - String to replace with

max - maximum number of values to replace, or -1 if no maximum

Returns:

the text with any replacements processed

hashCode

public static int hashCode(String s)

Parameters:

s - The String value to calculate the hash code on - may be null/empty in which case a value of zero is returned

Returns:

The calculated hash code

See Also:

hashCode(String, Boolean)

hashCode

public static int hashCode(String s,
                           Boolean useUppercase)

Parameters:

s - The String value to calculate the hash code on - may be null/empty in which case a value of zero is returned

useUppercase - Whether to convert the string to uppercase, lowercase or not at all:

• null - no conversion
• Boolean.TRUE - get hash code of uppercase
• Boolean.FALSE - get hash code of lowercase

Returns:

The calculated hash code

safeCompare

public static int safeCompare(String s1,
                              String s2,
                              boolean caseSensitive)

length

public static int length(CharSequence cs)

isEmpty

public static boolean isEmpty(CharSequence cs)

isNotEmpty

public static boolean isNotEmpty(CharSequence cs)

indexOf

public static int indexOf(CharSequence cs,
                          char c)

lastIndexOf

public static int lastIndexOf(CharSequence cs,
                              char c)

split

public static String[] split(String s,
                             char ch)

join

public static <T> String join(T[] values,
                              char ch)

join

public static String join(Iterable<?> iter,
                          char ch)

join

public static String join(Iterator<?> iter,
                          char ch)

join

public static <T> String join(T[] values,
                              CharSequence sep)

join

public static String join(Iterable<?> iter,
                          CharSequence sep)

join

public static String join(Iterator<?> iter,
                          CharSequence sep)

size

public static int size(Collection<?> c)

isEmpty

public static boolean isEmpty(Collection<?> c)

isNotEmpty

public static boolean isNotEmpty(Collection<?> c)

equals

public static <T> boolean equals(Collection<T> c1,
                                 Collection<T> c2)

Type Parameters:

T - Generic element type

Parameters:

c1 - First collection

c2 - Second collection

Returns:

true if the following holds:

• Same size - Note: null collections are consider equal to empty ones
• First collection contains all elements of second one and vice versa

length

@SafeVarargs
public static <T> int length(T... a)

isEmpty

public static <T> boolean isEmpty(Iterable<? extends T> iter)

isNotEmpty

public static <T> boolean isNotEmpty(Iterable<? extends T> iter)

isEmpty

public static <T> boolean isEmpty(Iterator<? extends T> iter)

isNotEmpty

public static <T> boolean isNotEmpty(Iterator<? extends T> iter)

isEmpty

public static <T> boolean isEmpty(T[] a)

length

public static int length(char[] chars)

isEmpty

public static boolean isEmpty(char[] chars)

compare

public static int compare(char[] c1,
                          char[] c2)

Compares 2 character arrays - Note: null and empty are considered equal

Parameters:

c1 - 1st array

c2 - 2nd array

Returns:

Negative is 1st array comes first in lexicographical order, positive if 2nd array comes first and zero if equal

of

@SafeVarargs
public static <E extends Enum<E>> Set<E> of(E... values)

of

public static <E extends Enum<E>> Set<E> of(Collection<? extends E> values)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(List<? extends T> c1,
                                                   List<? extends T> c2)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(List<? extends T> c1,
                                                   List<? extends T> c2,
                                                   UnaryEquator<? super T> equator)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(Iterable<? extends T> c1,
                                                   Iterable<? extends T> c2)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(Iterable<? extends T> c1,
                                                   Iterable<? extends T> c2,
                                                   UnaryEquator<? super T> equator)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(Iterator<? extends T> i1,
                                                   Iterator<? extends T> i2)

findFirstDifferentValueIndex

public static <T> int findFirstDifferentValueIndex(Iterator<? extends T> i1,
                                                   Iterator<? extends T> i2,
                                                   UnaryEquator<? super T> equator)

containsAny

public static <T> boolean containsAny(Collection<? extends T> coll,
                                      Iterable<? extends T> values)

forEach

public static <T> void forEach(Iterable<? extends T> values,
                               Consumer<? super T> consumer)

map

public static <T,U> List<U> map(Collection<? extends T> values,
                                Function<? super T,? extends U> mapper)

mapSort

public static <T,U> NavigableSet<U> mapSort(Collection<? extends T> values,
                                            Function<? super T,? extends U> mapper,
                                            Comparator<? super U> comparator)

toSortedSet

public static <T> Collector<T,?,NavigableSet<T>> toSortedSet(Comparator<? super T> comparator)

stream

public static <T> Stream<T> stream(Iterable<T> values)

unmodifiableList

@SafeVarargs
public static <T> List<T> unmodifiableList(T... values)

unmodifiableList

public static <T> List<T> unmodifiableList(Collection<? extends T> values)

unmodifiableList

public static <T> List<T> unmodifiableList(Stream<T> values)

asList

@SafeVarargs
public static <T> List<T> asList(T... values)

asSet

@SafeVarargs
public static <T> Set<T> asSet(T... values)

asSortedSet

@SafeVarargs
public static <V extends Comparable<V>> NavigableSet<V> asSortedSet(V... values)

asSortedSet

public static <V extends Comparable<V>> NavigableSet<V> asSortedSet(Collection<? extends V> values)

asSortedSet

@SafeVarargs
public static <V> NavigableSet<V> asSortedSet(Comparator<? super V> comp,
                                                           V... values)

Type Parameters:

V - The element type

Parameters:

comp - The (non-null) Comparator to use

values - The values to be added (ignored if null)

Returns:

A NavigableSet containing the values (if any) sorted using the provided comparator

asSortedSet

public static <V> NavigableSet<V> asSortedSet(Comparator<? super V> comp,
                                              Collection<? extends V> values)

Type Parameters:

V - The element type

Parameters:

comp - The (non-null) Comparator to use

values - The values to be added (ignored if null/empty)

Returns:

A NavigableSet containing the values (if any) sorted using the provided comparator

findFirstMatchingMember

@SafeVarargs
public static <T> T findFirstMatchingMember(Predicate<? super T> acceptor,
                                                         T... values)

findFirstMatchingMember

public static <T> T findFirstMatchingMember(Predicate<? super T> acceptor,
                                            Collection<? extends T> values)

selectMatchingMembers

@SafeVarargs
public static <T> List<T> selectMatchingMembers(Predicate<? super T> acceptor,
                                                             T... values)

Returns a list of all the values that were accepted by a predicate

Type Parameters:

T - The type of value being evaluated

Parameters:

acceptor - The Predicate to consult whether a member is selected

values - The values to be scanned

Returns:

A List of all the values that were accepted by the predicate

selectMatchingMembers

public static <T> List<T> selectMatchingMembers(Predicate<? super T> acceptor,
                                                Collection<? extends T> values)

Returns a list of all the values that were accepted by a predicate

Type Parameters:

T - The type of value being evaluated

Parameters:

acceptor - The Predicate to consult whether a member is selected

values - The values to be scanned

Returns:

A List of all the values that were accepted by the predicate

stripQuotes

public static CharSequence stripQuotes(CharSequence s)

Parameters:

s - The CharSequence to be checked

Returns:

If the sequence contains any of the QUOTES on both ends, then they are stripped, otherwise nothing is done

See Also:

stripDelimiters(CharSequence, char)

stripDelimiters

public static CharSequence stripDelimiters(CharSequence s,
                                           char delim)

Parameters:

s - The CharSequence to be checked

delim - The expected delimiter

Returns:

If the sequence contains the delimiter on both ends, then it is are stripped, otherwise nothing is done

supplierOf

public static <T> Supplier<T> supplierOf(T value)

Wraps a value into a Supplier

Type Parameters:

T - Type of value being supplied

Parameters:

value - The value to be supplied

Returns:

The supplier wrapper

iteratorOf

public static <T> Iterator<T> iteratorOf(Iterable<T> iterable)

Resolves to an always non-null iterator

Type Parameters:

T - Type of value being iterated

Parameters:

iterable - The Iterable instance

Returns:

A non-null iterator which may be empty if no iterable instance or no iterator returned from it

See Also:

iteratorOf(Iterator)

downcast

public static <B,D extends B> Function<D,B> downcast()

Type Parameters:

B - Generic base class

D - Generic child class

Returns:

An identity Function that returns its input child class as a base class

head

public static <T> T head(Iterable<? extends T> it)

Returns the first element in iterable - it has some optimization for List-s Deque-s and SortedSets.

Type Parameters:

T - Type of element

Parameters:

it - The Iterable instance - ignored if null/empty

Returns:

first element by iteration or null if none available

iteratorOf

public static <T> Iterator<T> iteratorOf(Iterator<T> iter)

Resolves to an always non-null iterator

Type Parameters:

T - Type of value being iterated

Parameters:

iter - The Iterator instance

Returns:

A non-null iterator which may be empty if no iterator instance

See Also:

Collections.emptyIterator()

wrapIterable

public static <U,V> Iterable<V> wrapIterable(Iterable<? extends U> iter,
                                             Function<? super U,? extends V> mapper)

wrapIterator

public static <U,V> Iterator<V> wrapIterator(Iterable<? extends U> iter,
                                             Function<? super U,? extends V> mapper)

wrapIterator

public static <U,V> Iterator<V> wrapIterator(Iterator<? extends U> iter,
                                             Function<? super U,? extends V> mapper)

selectNextMatchingValue

public static <T> T selectNextMatchingValue(Iterator<?> values,
                                            Class<T> type)

Type Parameters:

T - Generic return type

Parameters:

values - The source values - ignored if null

type - The (never @code null) type of values to select - any value whose type is assignable to this type will be selected by the iterator.

Returns:

The first value that matches the specified type - null if none found

multiIterableSuppliers

public static <T> Iterable<T> multiIterableSuppliers(Iterable<? extends Supplier<? extends Iterable<? extends T>>> providers)

Wraps a group of Suppliers of Iterable instances into a "unified" Iterable of their values, in the same order as the suppliers - i.e., once the values from a specific supplier are exhausted, the next one is consulted, and so on, until all suppliers have been consulted

Type Parameters:

T - Type of value being iterated

Parameters:

providers - The providers - ignored if null (i.e., return an empty iterable instance)

Returns:

The wrapping instance

memoizeLock

public static <T> Supplier<T> memoizeLock(Supplier<? extends T> delegate)

The delegate Suppliers get() method is called exactly once and the result is cached.

Type Parameters:

T - Generic type of supplied value

Parameters:

delegate - The actual Supplier

Returns:

The memoized Supplier

isPositive

public static boolean isPositive(Duration d)

Check if a duration is positive

Parameters:

d - the duration

Returns:

true if the duration is greater than zero

isNegativeOrNull

public static boolean isNegativeOrNull(Duration d)

Check if a duration is negative or zero

Parameters:

d - the duration

Returns:

true if the duration is negative or zero