org.glassfish.pfl.basic.algorithm

Class Algorithms

java.lang.Object

org.glassfish.pfl.basic.algorithm.Algorithms

public final class Algorithms
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Algorithms.Action<T>

Method Summary

Methods

Modifier and Type	Method and Description
static <A> UnaryPredicate<A>	and(UnaryPredicate<A> arg1, UnaryPredicate<A> arg2)
static List	convertToList(Object arg) Converts obj from an Array to a List, if obj is an array.
static String	convertToString(Object arg) Convert argument to String, either by toString, ot Arrays.toString.
static <T> T	doPrivileged(Algorithms.Action<T> func)
static <T> UnaryPredicate<T>	FALSE(Class<T> cls)
static <A> void	filter(List<A> arg, List<A> result, UnaryPredicate<A> predicate)
static <A> List<A>	filter(List<A> arg, UnaryPredicate<A> predicate)
static <A> A	find(List<A> arg, UnaryPredicate<A> predicate)
static <S,T> List<T>	flatten(List<S> list, UnaryFunction<S,List<T>> map) Flatten the results of applying map to list into a list of T.
static <A,R> R	fold(List<A> list, R initial, BinaryFunction<R,A,R> func)
static Map<String,Object>	getAnnotationValues(Annotation ann, boolean convertArraysToLists) Given an annotation, return a Map that maps each field (given by a method name) to its value in the annotation.
static <T> T	getFirst(Collection<T> list, Runnable handleEmptyList) Return the first element of the list, or invoke handleEmptyList if list is empty.
static <T> List<T>	list(T... arg)
static <A,R> void	map(Collection<A> arg, Collection<R> result, UnaryFunction<A,R> func)
static <A,R> List<R>	map(List<A> arg, UnaryFunction<A,R> func)
static <K,A,R> Map<K,R>	map(Map<K,A> arg, UnaryFunction<A,R> func)
static <K,V> Map<K,V>	map(Pair<K,V>... pairs)
static <A,R> UnaryFunction<A,R>	mapToFunction(Map<A,R> map)
static <A> UnaryPredicate<A>	not(UnaryPredicate<A> arg1)
static <A> UnaryPredicate<A>	or(UnaryPredicate<A> arg1, UnaryPredicate<A> arg2)
static <S,T> Pair<S,T>	pair(S first, T second)
static <T> UnaryPredicate<T>	TRUE(Class<T> cls)

Methods inherited from class java.lang.Object

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

Method Detail

list

public static <T> List<T> list(T... arg)

pair

public static <S,T> Pair<S,T> pair(S first,
                   T second)

map

public static <K,V> Map<K,V> map(Pair<K,V>... pairs)

mapToFunction

public static <A,R> UnaryFunction<A,R> mapToFunction(Map<A,R> map)

map

public static <A,R> void map(Collection<A> arg,
             Collection<R> result,
             UnaryFunction<A,R> func)

map

public static <K,A,R> Map<K,R> map(Map<K,A> arg,
                   UnaryFunction<A,R> func)

map

public static <A,R> List<R> map(List<A> arg,
                UnaryFunction<A,R> func)

and

public static <A> UnaryPredicate<A> and(UnaryPredicate<A> arg1,
                        UnaryPredicate<A> arg2)

or

public static <A> UnaryPredicate<A> or(UnaryPredicate<A> arg1,
                       UnaryPredicate<A> arg2)

FALSE

public static <T> UnaryPredicate<T> FALSE(Class<T> cls)

TRUE

public static <T> UnaryPredicate<T> TRUE(Class<T> cls)

not

public static <A> UnaryPredicate<A> not(UnaryPredicate<A> arg1)

filter

public static <A> void filter(List<A> arg,
              List<A> result,
              UnaryPredicate<A> predicate)

filter

public static <A> List<A> filter(List<A> arg,
                 UnaryPredicate<A> predicate)

find

public static <A> A find(List<A> arg,
         UnaryPredicate<A> predicate)

fold

public static <A,R> R fold(List<A> list,
           R initial,
           BinaryFunction<R,A,R> func)

flatten

public static <S,T> List<T> flatten(List<S> list,
                    UnaryFunction<S,List<T>> map)

Flatten the results of applying map to list into a list of T.

Type Parameters:

S - Type of elements of list.

T - Type of elements of result.

Parameters:

list - List of elements of type S.

map - function mapping S to List.

Returns:

List containg results of applying map to each element of list.

getFirst

public static <T> T getFirst(Collection<T> list,
             Runnable handleEmptyList)

Return the first element of the list, or invoke handleEmptyList if list is empty.

Type Parameters:

T - The type of the list element.

Parameters:

list - The list

handleEmptyList - A runnable to call when the list is empty. Typically throws an exception.

Returns:

The first element of the list, if any.

convertToList

public static List convertToList(Object arg)

Converts obj from an Array to a List, if obj is an array. Otherwise just returns a List containing obj.

convertToString

public static String convertToString(Object arg)

Convert argument to String, either by toString, ot Arrays.toString.

Parameters:

arg - Object to convert.

getAnnotationValues

public static Map<String,Object> getAnnotationValues(Annotation ann,
                                     boolean convertArraysToLists)

Given an annotation, return a Map that maps each field (given by a method name) to its value in the annotation. If the value is an annotation, that value is recursively converted into a Map in the same way.

Parameters:

ann - The annotation to examine.

convertArraysToLists - true if annotation values of array type should be converted to an appropriate list. This is often MUCH more useful, but some contexts require arrays.

Returns:

A map of annotation fields to their values.

doPrivileged

public static <T> T doPrivileged(Algorithms.Action<T> func)