Package com.ssgllc.fish.f.list

Class ListBuilder<U,V>

java.lang.Object

com.ssgllc.fish.f.list.ListBuilder<U,V>

public class ListBuilder<U,V>
extends Object

Folds a list to a single value, reached as f().list.

Constructor Summary

Constructors

Constructor	Description
ListBuilder()

Method Summary

Modifier and Type	Method	Description
ValueReducer<U,V>	reduce(List<U> items)	Starts a fold over a list.

Methods inherited from class java.lang.Object

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

Constructor Details

ListBuilder

public ListBuilder()

Method Details

reduce

public ValueReducer<U,V> reduce(List<U> items)

Starts a fold over a list. Continue with startingWith to supply the initial value.

This exists because neither dialect has a natural fold: a SpEL expression cannot hold a running variable, so summing or accumulating over a collection needs this shape.

Parameters:

items - the list to fold; null is treated as empty

Returns:

a reducer awaiting an initial value

Groovy example:
f().list.reduce(items).startingWith(0)

Returns:
a reducer ready to accumulate

SpEL example:
#f().list.reduce(#lineItems).startingWith(0)