Package org.apache.sshd.common.util

Class GenericUtils

  • public final class GenericUtils
extends java.lang.Object

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private GenericUtils()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <T extends java.lang.Throwable>
      T      		 accumulateException​(T current, T extra)
      Used to "accumulate" exceptions of the same type.
      static <T> java.util.List<T> asList​(T... values)  
      static <T> java.util.Set<T> asSet​(T... values)  
      static <V extends java.lang.Comparable<V>>
      java.util.NavigableSet<V>      		 asSortedSet​(java.util.Collection<? extends V> values)  
      static <V> java.util.NavigableSet<V> asSortedSet​(java.util.Comparator<? super V> comp, java.util.Collection<? extends V> values)  
      static <V> java.util.NavigableSet<V> asSortedSet​(java.util.Comparator<? super V> comp, V... values)  
      static <V extends java.lang.Comparable<V>>
      java.util.NavigableSet<V>      		 asSortedSet​(V... values)  
      static <V> java.util.function.Supplier<java.util.NavigableMap<java.lang.String,​V>> caseInsensitiveMap()  
      static int compare​(char[] c1, char[] c2)
      Compares 2 character arrays - Note: null and empty are considered equal
      static <T> boolean containsAny​(java.util.Collection<? extends T> coll, java.lang.Iterable<? extends T> values)  
      static <B,​D extends B>
      java.util.function.Function<D,​B>      		 downcast()  
      static <T> int findFirstDifferentValueIndex​(java.lang.Iterable<? extends T> c1, java.lang.Iterable<? extends T> c2)  
      static <T> int findFirstDifferentValueIndex​(java.lang.Iterable<? extends T> c1, java.lang.Iterable<? extends T> c2, UnaryEquator<? super T> equator)  
      static <T> int findFirstDifferentValueIndex​(java.util.Iterator<? extends T> i1, java.util.Iterator<? extends T> i2)  
      static <T> int findFirstDifferentValueIndex​(java.util.Iterator<? extends T> i1, java.util.Iterator<? extends T> i2, UnaryEquator<? super T> equator)  
      static <T> int findFirstDifferentValueIndex​(java.util.List<? extends T> c1, java.util.List<? extends T> c2)  
      static <T> int findFirstDifferentValueIndex​(java.util.List<? extends T> c1, java.util.List<? extends T> c2, UnaryEquator<? super T> equator)  
      static <T> T findFirstMatchingMember​(java.util.function.Predicate<? super T> acceptor, java.util.Collection<? extends T> values)  
      static <T> T findFirstMatchingMember​(java.util.function.Predicate<? super T> acceptor, T... values)  
      static <K,​V,​M extends java.util.Map<V,​K>>
      M      		 flipMap​(java.util.Map<? extends K,​? extends V> map, java.util.function.Supplier<? extends M> mapCreator, boolean allowDuplicates)
      Flips between keys and values of an input map
      static <T> void forEach​(java.lang.Iterable<? extends T> values, java.util.function.Consumer<? super T> consumer)  
      static int hashCode​(java.lang.String s)  
      static int hashCode​(java.lang.String s, java.lang.Boolean useUppercase)  
      static <T> T head​(java.lang.Iterable<? extends T> it)
      Returns the first element in iterable - it has some optimization for List-s Deque-s and SortedSets.
      static int indexOf​(java.lang.CharSequence cs, char c)  
      static boolean isEmpty​(char[] chars)  
      static boolean isEmpty​(java.lang.CharSequence cs)  
      static <T> boolean isEmpty​(java.lang.Iterable<? extends T> iter)  
      static boolean isEmpty​(java.util.Collection<?> c)  
      static <T> boolean isEmpty​(java.util.Iterator<? extends T> iter)  
      static boolean isEmpty​(java.util.Map<?,​?> m)  
      static <T> boolean isEmpty​(T... a)  
      static boolean isNotEmpty​(java.lang.CharSequence cs)  
      static <T> boolean isNotEmpty​(java.lang.Iterable<? extends T> iter)  
      static boolean isNotEmpty​(java.util.Collection<?> c)  
      static <T> boolean isNotEmpty​(java.util.Iterator<? extends T> iter)  
      static boolean isNotEmpty​(java.util.Map<?,​?> m)  
      static <T> boolean isSameReference​(T o1, T o2)  
      static <T> java.util.Iterator<T> iteratorOf​(java.lang.Iterable<T> iterable)
      Resolves to an always non-null iterator
      static <T> java.util.Iterator<T> iteratorOf​(java.util.Iterator<T> iter)
      Resolves to an always non-null iterator
      static java.lang.String join​(java.lang.Iterable<?> iter, char ch)  
      static java.lang.String join​(java.lang.Iterable<?> iter, java.lang.CharSequence sep)  
      static java.lang.String join​(java.util.Iterator<?> iter, char ch)  
      static java.lang.String join​(java.util.Iterator<?> iter, java.lang.CharSequence sep)  
      static <T> java.lang.String join​(T[] values, char ch)  
      static <T> java.lang.String join​(T[] values, java.lang.CharSequence sep)  
      static int lastIndexOf​(java.lang.CharSequence cs, char c)  
      static int length​(char[] chars)  
      static int length​(java.lang.CharSequence cs)  
      static <T> int length​(T... a)  
      static <T,​U>
      java.util.List<U>      		 map​(java.util.Collection<? extends T> values, java.util.function.Function<? super T,​? extends U> mapper)  
      static <T,​U>
      java.util.NavigableSet<U>      		 mapSort​(java.util.Collection<? extends T> values, java.util.function.Function<? super T,​? extends U> mapper, java.util.Comparator<? super U> comparator)  
      static <K,​V,​M extends java.util.Map<K,​V>>
      M      		 mapValues​(java.util.function.Function<? super V,​? extends K> keyMapper, java.util.function.Supplier<? extends M> mapCreator, java.util.Collection<? extends V> values)
      Creates a map out of a group of values
      static <K,​V,​M extends java.util.Map<K,​V>>
      M      		 mapValues​(java.util.function.Function<? super V,​? extends K> keyMapper, java.util.function.Supplier<? extends M> mapCreator, V... values)  
      static <T> java.lang.Iterable<T> multiIterableSuppliers​(java.lang.Iterable<? extends java.util.function.Supplier<? extends java.lang.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 java.lang.Enum<E>>
      java.util.Set<E>      		 of​(E... values)  
      static <E extends java.lang.Enum<E>>
      java.util.Set<E>      		 of​(java.util.Collection<? extends E> values)  
      static java.lang.Throwable peelException​(java.lang.Throwable t)
      Attempts to get to the "effective" exception being thrown, by taking care of some known exceptions that wrap the original thrown one.
      static java.lang.String replaceWhitespaceAndTrim​(java.lang.String s)  
      static java.lang.Throwable resolveExceptionCause​(java.lang.Throwable t)  
      static int safeCompare​(java.lang.String s1, java.lang.String s2, boolean caseSensitive)  
      static <T> java.util.List<T> selectMatchingMembers​(java.util.function.Predicate<? super T> acceptor, java.util.Collection<? extends T> values)
      Returns a list of all the values that were accepted by a predicate
      static <T> java.util.List<T> selectMatchingMembers​(java.util.function.Predicate<? super T> acceptor, T... values)
      Returns a list of all the values that were accepted by a predicate
      static <T> T selectNextMatchingValue​(java.util.Iterator<?> values, java.lang.Class<T> type)  
      static int size​(java.util.Collection<?> c)  
      static int size​(java.util.Map<?,​?> m)  
      static java.lang.String[] split​(java.lang.String s, char ch)  
      static <T> java.util.stream.Stream<T> stream​(java.lang.Iterable<T> values)  
      static java.lang.CharSequence stripDelimiters​(java.lang.CharSequence s, char delim)  
      static java.lang.CharSequence stripQuotes​(java.lang.CharSequence s)  
      static <T> java.util.function.Supplier<T> supplierOf​(T value)
      Wraps a value into a Supplier
      static <T> java.util.function.BinaryOperator<T> throwingMerger()  
      static java.io.IOException toIOException​(java.lang.Throwable e)  
      static java.lang.RuntimeException toRuntimeException​(java.lang.Throwable t)  
      static java.lang.RuntimeException toRuntimeException​(java.lang.Throwable t, boolean peelThrowable)
      Converts a thrown generic exception to a RuntimeException
      static <T,​K,​U>
      java.util.NavigableMap<K,​U>      		 toSortedMap​(java.lang.Iterable<? extends T> values, java.util.function.Function<? super T,​? extends K> keyMapper, java.util.function.Function<? super T,​? extends U> valueMapper, java.util.Comparator<? super K> comparator)  
      static <T,​K,​U>
      java.util.stream.Collector<T,​?,​java.util.NavigableMap<K,​U>>      		 toSortedMap​(java.util.function.Function<? super T,​? extends K> keyMapper, java.util.function.Function<? super T,​? extends U> valueMapper, java.util.Comparator<? super K> comparator)  
      static <T> java.util.stream.Collector<T,​?,​java.util.NavigableSet<T>> toSortedSet​(java.util.Comparator<? super T> comparator)  
      static java.lang.String trimToEmpty​(java.lang.String s)  
      static <T> java.util.List<T> unmodifiableList​(java.util.Collection<? extends T> values)  
      static <T> java.util.List<T> unmodifiableList​(java.util.stream.Stream<T> values)  
      static <T> java.util.List<T> unmodifiableList​(T... values)  
      static <U,​V>
      java.lang.Iterable<V>      		 wrapIterable​(java.lang.Iterable<? extends U> iter, java.util.function.Function<? super U,​? extends V> mapper)  
      static <U,​V>
      java.util.Iterator<V>      		 wrapIterator​(java.lang.Iterable<? extends U> iter, java.util.function.Function<? super U,​? extends V> mapper)  
      static <U,​V>
      java.util.Iterator<V>      		 wrapIterator​(java.util.Iterator<? extends U> iter, java.util.function.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 java.lang.String[] EMPTY_STRING_ARRAY

      • EMPTY_OBJECT_ARRAY

        public static final java.lang.Object[] EMPTY_OBJECT_ARRAY

      • EMPTY_BOOLEAN_ARRAY

        public static final boolean[] EMPTY_BOOLEAN_ARRAY

      • NULL

        public static final java.lang.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 java.util.Comparator<java.lang.String> CASE_SENSITIVE_ORDER
        The complement of String.CASE_INSENSITIVE_ORDER

      • CASE_INSENSITIVE_MAP_FACTORY

        private static final java.util.function.Supplier CASE_INSENSITIVE_MAP_FACTORY

    • Constructor Detail

      • GenericUtils

        private GenericUtils()

    • Method Detail

      • trimToEmpty

        public static java.lang.String trimToEmpty​(java.lang.String s)

      • replaceWhitespaceAndTrim

        public static java.lang.String replaceWhitespaceAndTrim​(java.lang.String s)

      • hashCode

        public static int hashCode​(java.lang.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​(java.lang.String s,
                           java.lang.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​(java.lang.String s1,
                              java.lang.String s2,
                              boolean caseSensitive)

      • isSameReference

        public static <T> boolean isSameReference​(T o1,
                                          T o2)

      • length

        public static int length​(java.lang.CharSequence cs)

      • isEmpty

        public static boolean isEmpty​(java.lang.CharSequence cs)

      • isNotEmpty

        public static boolean isNotEmpty​(java.lang.CharSequence cs)

      • indexOf

        public static int indexOf​(java.lang.CharSequence cs,
                          char c)

      • lastIndexOf

        public static int lastIndexOf​(java.lang.CharSequence cs,
                              char c)

      • split

        public static java.lang.String[] split​(java.lang.String s,
                                       char ch)

      • join

        public static <T> java.lang.String join​(T[] values,
                                        char ch)

      • join

        public static java.lang.String join​(java.lang.Iterable<?> iter,
                                    char ch)

      • join

        public static java.lang.String join​(java.util.Iterator<?> iter,
                                    char ch)

      • join

        public static <T> java.lang.String join​(T[] values,
                                        java.lang.CharSequence sep)

      • join

        public static java.lang.String join​(java.lang.Iterable<?> iter,
                                    java.lang.CharSequence sep)

      • join

        public static java.lang.String join​(java.util.Iterator<?> iter,
                                    java.lang.CharSequence sep)

      • size

        public static int size​(java.util.Collection<?> c)

      • isEmpty

        public static boolean isEmpty​(java.util.Collection<?> c)

      • isNotEmpty

        public static boolean isNotEmpty​(java.util.Collection<?> c)

      • size

        public static int size​(java.util.Map<?,​?> m)

      • isEmpty

        public static boolean isEmpty​(java.util.Map<?,​?> m)

      • isNotEmpty

        public static boolean isNotEmpty​(java.util.Map<?,​?> m)

      • length

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

      • isEmpty

        public static <T> boolean isEmpty​(java.lang.Iterable<? extends T> iter)

      • isNotEmpty

        public static <T> boolean isNotEmpty​(java.lang.Iterable<? extends T> iter)

      • isEmpty

        public static <T> boolean isEmpty​(java.util.Iterator<? extends T> iter)

      • isNotEmpty

        public static <T> boolean isNotEmpty​(java.util.Iterator<? extends T> iter)

      • isEmpty

        @SafeVarargs
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 java.lang.Enum<E>> java.util.Set<E> of​(E... values)

      • of

        public static <E extends java.lang.Enum<E>> java.util.Set<E> of​(java.util.Collection<? extends E> values)

      • findFirstDifferentValueIndex

        public static <T> int findFirstDifferentValueIndex​(java.util.List<? extends T> c1,
                                                   java.util.List<? extends T> c2)

      • findFirstDifferentValueIndex

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

      • findFirstDifferentValueIndex

        public static <T> int findFirstDifferentValueIndex​(java.lang.Iterable<? extends T> c1,
                                                   java.lang.Iterable<? extends T> c2)

      • findFirstDifferentValueIndex

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

      • findFirstDifferentValueIndex

        public static <T> int findFirstDifferentValueIndex​(java.util.Iterator<? extends T> i1,
                                                   java.util.Iterator<? extends T> i2)

      • findFirstDifferentValueIndex

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

      • containsAny

        public static <T> boolean containsAny​(java.util.Collection<? extends T> coll,
                                      java.lang.Iterable<? extends T> values)

      • forEach

        public static <T> void forEach​(java.lang.Iterable<? extends T> values,
                               java.util.function.Consumer<? super T> consumer)

      • map

        public static <T,​U> java.util.List<U> map​(java.util.Collection<? extends T> values,
                                                java.util.function.Function<? super T,​? extends U> mapper)

      • mapSort

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

      • toSortedMap

        public static <T,​K,​U> java.util.NavigableMap<K,​U> toSortedMap​(java.lang.Iterable<? extends T> values,
                                                                                java.util.function.Function<? super T,​? extends K> keyMapper,
                                                                                java.util.function.Function<? super T,​? extends U> valueMapper,
                                                                                java.util.Comparator<? super K> comparator)

      • toSortedMap

        public static <T,​K,​U> java.util.stream.Collector<T,​?,​java.util.NavigableMap<K,​U>> toSortedMap​(java.util.function.Function<? super T,​? extends K> keyMapper,
                                                                                                                            java.util.function.Function<? super T,​? extends U> valueMapper,
                                                                                                                            java.util.Comparator<? super K> comparator)

      • throwingMerger

        public static <T> java.util.function.BinaryOperator<T> throwingMerger()

      • toSortedSet

        public static <T> java.util.stream.Collector<T,​?,​java.util.NavigableSet<T>> toSortedSet​(java.util.Comparator<? super T> comparator)

      • stream

        public static <T> java.util.stream.Stream<T> stream​(java.lang.Iterable<T> values)

      • unmodifiableList

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

      • unmodifiableList

        public static <T> java.util.List<T> unmodifiableList​(java.util.Collection<? extends T> values)

      • unmodifiableList

        public static <T> java.util.List<T> unmodifiableList​(java.util.stream.Stream<T> values)

      • asList

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

      • asSet

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

      • asSortedSet

        @SafeVarargs
public static <V extends java.lang.Comparable<V>> java.util.NavigableSet<V> asSortedSet​(V... values)

      • asSortedSet

        public static <V extends java.lang.Comparable<V>> java.util.NavigableSet<V> asSortedSet​(java.util.Collection<? extends V> values)

      • asSortedSet

        @SafeVarargs
public static <V> java.util.NavigableSet<V> asSortedSet​(java.util.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> java.util.NavigableSet<V> asSortedSet​(java.util.Comparator<? super V> comp,
                                                        java.util.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

      • caseInsensitiveMap

        public static <V> java.util.function.Supplier<java.util.NavigableMap<java.lang.String,​V>> caseInsensitiveMap()
        Type Parameters:
        V - Type of mapped value
        Returns:
        A Supplier that returns a new NavigableMap whenever its get() method is invoked

      • flipMap

        public static <K,​V,​M extends java.util.Map<V,​K>> M flipMap​(java.util.Map<? extends K,​? extends V> map,
                                                                             java.util.function.Supplier<? extends M> mapCreator,
                                                                             boolean allowDuplicates)
        Flips between keys and values of an input map
        Type Parameters:
        K - Original map key type
        V - Original map value type
        M - Flipped map type
        Parameters:
        map - The original map to flip
        mapCreator - The creator of the target map
        allowDuplicates - Whether to ignore duplicates on flip
        Returns:
        The flipped map result
        Throws:
        java.lang.IllegalArgumentException - if allowDuplicates is false and a duplicate value found in the original map.

      • mapValues

        @SafeVarargs
public static <K,​V,​M extends java.util.Map<K,​V>> M mapValues​(java.util.function.Function<? super V,​? extends K> keyMapper,
                                                                               java.util.function.Supplier<? extends M> mapCreator,
                                                                               V... values)

      • mapValues

        public static <K,​V,​M extends java.util.Map<K,​V>> M mapValues​(java.util.function.Function<? super V,​? extends K> keyMapper,
                                                                               java.util.function.Supplier<? extends M> mapCreator,
                                                                               java.util.Collection<? extends V> values)
        Creates a map out of a group of values
        Type Parameters:
        K - The key type
        V - The value type
        M - The result Map type
        Parameters:
        keyMapper - The Function that generates a key for a given value. If the returned key is null then the value is not mapped
        mapCreator - The Supplier used to create/retrieve the result map - provided non-empty group of values
        values - The values to be mapped
        Returns:
        The resulting Map - Note: no validation is made to ensure that 2 (or more) values are not mapped to the same key

      • findFirstMatchingMember

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

      • findFirstMatchingMember

        public static <T> T findFirstMatchingMember​(java.util.function.Predicate<? super T> acceptor,
                                            java.util.Collection<? extends T> values)

      • selectMatchingMembers

        @SafeVarargs
public static <T> java.util.List<T> selectMatchingMembers​(java.util.function.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> java.util.List<T> selectMatchingMembers​(java.util.function.Predicate<? super T> acceptor,
                                                          java.util.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 java.lang.CharSequence stripQuotes​(java.lang.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 java.lang.CharSequence stripDelimiters​(java.lang.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

      • toRuntimeException

        public static java.lang.RuntimeException toRuntimeException​(java.lang.Throwable t)

      • toRuntimeException

        public static java.lang.RuntimeException toRuntimeException​(java.lang.Throwable t,
                                                            boolean peelThrowable)
        Converts a thrown generic exception to a RuntimeException
        Parameters:
        t - The original thrown exception
        peelThrowable - Whether to determine the root cause by "peeling" any enclosing exceptions
        Returns:
        The thrown cause if already a runtime exception, otherwise a runtime exception of the resolved exception as its cause
        See Also:
        peelException(Throwable)

      • peelException

        public static java.lang.Throwable peelException​(java.lang.Throwable t)
        Attempts to get to the "effective" exception being thrown, by taking care of some known exceptions that wrap the original thrown one.
        Parameters:
        t - The original Throwable - ignored if null
        Returns:
        The effective exception - same as input if not a wrapper

      • resolveExceptionCause

        public static java.lang.Throwable resolveExceptionCause​(java.lang.Throwable t)
        Parameters:
        t - The original Throwable - ignored if null
        Returns:
        If Throwable.getCause() is non-null then the cause, otherwise the original exception - null if the original exception was null

      • accumulateException

        public static <T extends java.lang.Throwable> T accumulateException​(T current,
                                                                    T extra)
        Used to "accumulate" exceptions of the same type. If the current exception is null then the new one becomes the current, otherwise the new one is added as a suppressed exception to the current one
        Type Parameters:
        T - The exception type
        Parameters:
        current - The current exception
        extra - The extra/new exception
        Returns:
        The resolved exception
        See Also:
        Throwable.addSuppressed(Throwable)

      • toIOException

        public static java.io.IOException toIOException​(java.lang.Throwable e)

      • supplierOf

        public static <T> java.util.function.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> java.util.Iterator<T> iteratorOf​(java.lang.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> java.util.function.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​(java.lang.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> java.util.Iterator<T> iteratorOf​(java.util.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> java.lang.Iterable<V> wrapIterable​(java.lang.Iterable<? extends U> iter,
                                                             java.util.function.Function<? super U,​? extends V> mapper)

      • wrapIterator

        public static <U,​V> java.util.Iterator<V> wrapIterator​(java.lang.Iterable<? extends U> iter,
                                                             java.util.function.Function<? super U,​? extends V> mapper)

      • wrapIterator

        public static <U,​V> java.util.Iterator<V> wrapIterator​(java.util.Iterator<? extends U> iter,
                                                             java.util.function.Function<? super U,​? extends V> mapper)

      • selectNextMatchingValue

        public static <T> T selectNextMatchingValue​(java.util.Iterator<?> values,
                                            java.lang.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> java.lang.Iterable<T> multiIterableSuppliers​(java.lang.Iterable<? extends java.util.function.Supplier<? extends java.lang.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