uk.gov.gchq.koryphe.util

Class IterableUtil

java.lang.Object

uk.gov.gchq.koryphe.util.IterableUtil

public final class IterableUtil
extends Object

An IterableUtil is a utility class providing capabilities for:

• Lazily applying a Function, or a List of Functions, to each element of an Iterable
• Flatmapping of nested Iterables via concatenation, to allow correct closing of the iterables

Method Summary

Modifier and Type	Method and Description
static <T> CloseableIterable<T>	concat(Iterable<? extends Iterable<? extends T>> iterables)
static <T> CloseableIterable<T>	filter(Iterable<T> iterable, List<Predicate> predicates) Filters items out of an iterable.
static <T> CloseableIterable<T>	filter(Iterable<T> iterable, Predicate predicate) Filters items out of an iterable.
static <T> CloseableIterable<T>	limit(Iterable<T> iterable, int start, Integer end, boolean truncate)
static <I_ITEM,O_ITEM> CloseableIterable<O_ITEM>	map(Iterable<I_ITEM> iterable, Function function)
static <I_ITEM,O_ITEM> CloseableIterable<O_ITEM>	map(Iterable<I_ITEM> iterable, List<Function> functions)

Methods inherited from class java.lang.Object

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

Method Detail

filter

public static <T> CloseableIterable<T> filter(Iterable<T> iterable,
                                              Predicate predicate)

Filters items out of an iterable. If the predicate returns false then an item is not valid and is removed.

Type Parameters:

T - the type of the items in the iterable

Parameters:

iterable - the items to filter

predicate - the predicate to apply

Returns:

the lazily filtered iterable

filter

public static <T> CloseableIterable<T> filter(Iterable<T> iterable,
                                              List<Predicate> predicates)

Filters items out of an iterable. If any predicate returns false then an item is not valid and is removed.

Type Parameters:

T - the type of the items in the iterable

Parameters:

iterable - the items to filter

predicates - the predicates to apply

Returns:

the lazily filtered iterable

map

public static <I_ITEM,O_ITEM> CloseableIterable<O_ITEM> map(Iterable<I_ITEM> iterable,
                                                            Function function)

map

public static <I_ITEM,O_ITEM> CloseableIterable<O_ITEM> map(Iterable<I_ITEM> iterable,
                                                            List<Function> functions)

concat

public static <T> CloseableIterable<T> concat(Iterable<? extends Iterable<? extends T>> iterables)

limit

public static <T> CloseableIterable<T> limit(Iterable<T> iterable,
                                             int start,
                                             Integer end,
                                             boolean truncate)