ExecutionStep

All Implemented Interfaces:
```
public interface ExecutionStep<T extends Object>

                    
```
A single execution step in a chain, represented as a pre-computed value or a callback provided by user.
Result of the ExecutionStep will be then asynchronously processed by Joiner as follows:
- return as is, if the result is a java.util.concurrent.CompletableFuture, for cases like: map, filter etc
- run the DB query, if the result is a cz.encircled.joiner.query.JoinerQuery
- otherwise, do persist an entity (or list of entities) and return its reference

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description

Field Summary

Fields
Modifier and Type	Field	Description

Constructor Summary

Constructors
Constructor	Description

Enum Constant Summary

Enum Constants
Enum Constant	Description

Method Summary

Modifier and Type	Method	Description
`abstract T`	`perform(Object arg)`	Execute a user callback or return pre-computed value
`Object`	`convertResult(List<Object> arg)`	Convert step result if needed (e.g.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
- Method Detail
  - perform
```
 abstract T perform(Object arg)
```
    Execute a user callback or return pre-computed value
  - convertResult
```
 Object convertResult(List<Object> arg)
```
    Convert step result if needed (e.g. wrap as Optional in case of nullable steps, or extract a singular value in case of findOne)
    
    Parameters:
    
    arg - initial step result, always passed as a List, even in case of functions like findOne