SingletonCollector (core 1.2.6 API)

java.lang.Object
- nva.commons.core.SingletonCollector

public final class SingletonCollector
extends java.lang.Object

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`ONLY_ELEMENT`
`static int`	`SINGLETON`
`static java.lang.String`	`SINGLETON_EXPECTED_ERROR_TEMPLATE`
`static java.lang.String`	`SINGLETON_OR_NULL_EXPECTED_ERROR_TEMPLATE`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static <T> java.util.stream.Collector<T,?,T>`	`collect()`	A utility to collect and return singletons from lists.
`static <T> java.util.stream.Collector<T,?,T>`	`collectOrElse(T alternative)`
`static <T,E extends java.lang.Exception> java.util.stream.Collector<T,?,Try<T>>`	`tryCollect()`	A utility to return a singleton from a list that is expected to contain one and only one item, throwing supplied exception if the list is empty or does not contain one element.

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

- Field Detail
  - SINGLETON
```
public static final int SINGLETON
```
    See Also:
    
    Constant Field Values
  - ONLY_ELEMENT
```
public static final int ONLY_ELEMENT
```
    See Also:
    
    Constant Field Values
  - SINGLETON_EXPECTED_ERROR_TEMPLATE
```
public static final java.lang.String SINGLETON_EXPECTED_ERROR_TEMPLATE
```
    See Also:
    
    Constant Field Values
  - SINGLETON_OR_NULL_EXPECTED_ERROR_TEMPLATE
```
public static final java.lang.String SINGLETON_OR_NULL_EXPECTED_ERROR_TEMPLATE
```
    See Also:
    
    Constant Field Values
- Method Detail
  - collect
```
public static <T> java.util.stream.Collector<T,?,T> collect()
```
    A utility to collect and return singletons from lists.
    
    Type Parameters:
    
    T - the type of input elements to the reduction operation.
    
    Returns:
    
    a singleton of type T.
  - collectOrElse
```
public static <T> java.util.stream.Collector<T,?,T> collectOrElse(T alternative)
```
  - tryCollect
```
public static <T,E extends java.lang.Exception> java.util.stream.Collector<T,?,Try<T>> tryCollect()
```
    A utility to return a singleton from a list that is expected to contain one and only one item, throwing supplied exception if the list is empty or does not contain one element.
    
    Type Parameters:
    
    T - The type of input elements to the reduction operation.
    
    E - The type of the exception to be thrown.
    
    Returns:
    
    A type of the singleton.