#include <Results.h>

Public Member Functions
	EBusReduceResult (T &rhs, const Aggregator &aggregator=Aggregator())

void	operator= (T &&rhs)

void	operator= (const T &rhs)

EBusReduceResult &	operator= (const EBusReduceResult &)=delete

Public Attributes
T &	value

Aggregator	unary

Detailed Description

template<class T, class Aggregator>
struct AZ::EBusReduceResult< T &, Aggregator >

Aggregates results returned by all handlers of an EBus event. Also puts the aggregated value into the input value that is passed by reference. You can use this structure to add results, apply a logical AND to results, and so on.

Template Parameters

T	The output type of the aggregator.
Aggregator	A function object that aggregates results. The return type must match T. For examples of function objects that you can use as aggregators, see functional_basic.h.

The following example replaces the value returned by a handler with the sum of the value and previous handler return values.

int myExistingInt = 5;
EBusReduceResult<int&, AZStd::plus<int>> result(myExistingInt);
MyBus::BroadcastResult(result, &MyBus::Events::GetANumber);
AZ_Printf("%d", result.value); // or AZ_Printf("%d", myExistingInt);

The following example determines whether all handlers, including the latest handler, return true. Also replaces the latest handler result with the aggregated result.

bool myExistingBool = true;
EBusReduceResult<bool&, AZStd::logical_and<bool>> result(myExistingBool);
MyBus::BroadcastResult(result, &MyBus::Events::IsDoneDoingThing);
// myExistingBool is now only true if all handlers returned true.
AZ_Printf("%d", myExistingBool);

Constructor & Destructor Documentation

◆ EBusReduceResult()

template<class T , class Aggregator >

AZ::EBusReduceResult< T &, Aggregator >::EBusReduceResult	(	T &	rhs,
		const Aggregator &	aggregator = `Aggregator()`
	)

inlineexplicit

Creates an instance of the class, sets the reference to the initial value, and sets the function object to use as the aggregator.

Parameters

rhs	A reference to the initial value, which new values will be aggregated with.
aggregator	A function object to aggregate the values. For examples of function objects that you can use as aggregators, see functional_basic.h.