Type Parameters:

V - The value type of the Result.

E - The error type of the Result.

All Known Implementing Classes:

Err, Ok
```
public interface Result<V,E>
```
The Result type is an alternative way of chaining together functions in a functional programming style while hiding away error handling structures such as try-catch-blocks and conditionals.
Instead of adding a throws declaration to a function, the return type of the function is instead set to Result
where V is the original return type, i.e. the "happy case" and E is the error type, usually the Exception type or a String if an error explanation is sufficient.

Example:
```
 public Result divide(int a, int b) {
        if (b == 0) {
                return Result.err("Can't divide by zero!");
        } else {
                return Result.ok(a / b);
        }
 }
 
```

Method Summary

All Methods Static Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`accept(ConsumerWithException<? super V> ok, ConsumerWithException<? super E> err)`	Terminal function that processes the result or the error
`<X> Result<X,E>`	`asError()`
`static <V,E> Result<V,E>`	`err(E error)`	Returns an `Err` containing the specified `error`.
`static <V> Result<V,java.lang.String>`	`err(java.lang.String format, java.lang.Object... args)`
`java.util.Optional<E>`	`error()`	Returns the error of this instance as an `Optional`.
`<U> Result<U,E>`	`flatMap(FunctionWithException<? super V,? extends Result<? extends U,? extends E>> mapper)`	FlatMap the contained value if this is an `Ok` value.
`boolean`	`isErr()`	Returns `true` if this instance represents an `Err` value, `false` otherwise.
`boolean`	`isOk()`	Returns `true` if this instance represents an `Ok` value, `false` otherwise.
`<U> Result<U,E>`	`map(FunctionWithException<? super V,? extends U> mapper)`	Map the contained value if this is an `Ok` value.
`<F> Result<V,F>`	`mapErr(FunctionWithException<? super E,? extends F> mapper)`	Map the contained error if this is an `Err` value.
`static <V,E> Result<V,E>`	`of(V value, E error)`	Returns an `Ok` if the `value` parameter is non-`null` or an `Err` otherwise.
`static <V,E> Result<V,E>`	`ok(V value)`	Returns an `Ok` containing the specified `value`.
`V`	`orElse(V orElse)`	Returns the contained value if this is an `Ok` value.
`V`	`orElseGet(java.util.function.Supplier<? extends V> orElseSupplier)`	Returns the contained value if this is an `Ok` value.
`<R extends java.lang.Throwable> V`	`orElseThrow(FunctionWithException<? super E,? extends R> throwableSupplier)`	Returns the contained value if this is an `Ok` value.
`Result<V,E>`	`recover(FunctionWithException<? super E,? extends V> recover)`	Recover the contained error if this is an `Err` value.
`V`	`unwrap()`	Returns the contained value if this is an `Ok` value.
`V`	`unwrap(java.lang.String message)`	Express the expectation that this object is an `Ok` value.
`<X extends java.lang.Throwable> V`	`unwrap(java.util.function.Function<E,X> constructor)`
`java.util.Optional<V>`	`value()`	Returns the value of this instance as an `Optional`.

- Method Detail
  - of
```
static <V,E> Result<V,E> of(V value,
                                        E error)
```
    Returns an Ok if the value parameter is non-null or an Err otherwise. Either one of value or error must not be null.
    
    Type Parameters:
    
    V - The value type of the Result.
    
    E - The error type of the Result.
    
    Parameters:
    
    value - If non-null, an Ok result is returned with the specified value.
    
    error - If value is null, an Err result is returned with the specified error.
    
    Returns:
    
    An Ok if the value parameter is non-null or an Err otherwise.
  - ok
```
static <V,E> Result<V,E> ok(V value)
```
    Returns an Ok containing the specified value.
    
    Type Parameters:
    
    V - The value type of the Result.
    
    E - The error type of the Result.
    
    Parameters:
    
    value - The value to contain in the Ok result. Must not be null.
    
    Returns:
    
    An Ok result.
  - err
```
static <V,E> Result<V,E> err(E error)
```
    Returns an Err containing the specified error.
    
    Type Parameters:
    
    V - The value type of the Result.
    
    E - The error type of the Result.
    
    Parameters:
    
    error - The error to contain in the Err result. Must not be null.
    
    Returns:
    
    An Err result.
  - err
```
static <V> Result<V,java.lang.String> err(java.lang.String format,
                                                java.lang.Object... args)
```
  - isOk
```
boolean isOk()
```
    Returns true if this instance represents an Ok value, false otherwise.
    
    Returns:
    
    true if this instance represents an Ok value, false otherwise.
  - isErr
```
boolean isErr()
```
    Returns true if this instance represents an Err value, false otherwise.
    
    Returns:
    
    true if this instance represents an Err value, false otherwise.
  - value
```
java.util.Optional<V> value()
```
    Returns the value of this instance as an Optional. Returns Optional.empty() if this is an Err instance.
    
    Returns:
    
    The value of this instance as an Optional. Returns Optional.empty() if this is an Err instance.
  - error
```
java.util.Optional<E> error()
```
    Returns the error of this instance as an Optional. Returns Optional.empty() if this is an Ok instance.
    
    Returns:
    
    The error of this instance as an Optional. Returns Optional.empty() if this is an Ok instance.
  - unwrap
```
V unwrap()
```
    Returns the contained value if this is an Ok value. Otherwise throws a ResultException.
    
    Returns:
    
    The contained value
    
    Throws:
    
    ResultException - If this is an Err instance.
  - unwrap
```
V unwrap(java.lang.String message)
```
    Express the expectation that this object is an Ok value. Otherwise throws a ResultException with the specified message.
    
    Parameters:
    
    message - The message to pass to a potential ResultException.
    
    Throws:
    
    ResultException - If this is an Err instance.
  - orElse
```
V orElse(V orElse)
```
    Returns the contained value if this is an Ok value. Otherwise returns the specified alternate value.
    
    Parameters:
    
    orElse - The value to return if this is an Err instance.
    
    Returns:
    
    The contained value or the alternate value
  - orElseGet
```
V orElseGet(java.util.function.Supplier<? extends V> orElseSupplier)
```
    Returns the contained value if this is an Ok value. Otherwise returns the alternate value supplied by the specified supplier.
    
    Parameters:
    
    orElseSupplier - The supplier to supply an alternate value if this is an Err instance. Must not be null.
    
    Returns:
    
    The contained value or the alternate value
  - orElseThrow
```
<R extends java.lang.Throwable> V orElseThrow(FunctionWithException<? super E,? extends R> throwableSupplier)
                                       throws R extends java.lang.Throwable
```
    Returns the contained value if this is an Ok value. Otherwise throws the exception supplied by the specified function.
    
    Type Parameters:
    
    R - The exception type.
    
    Parameters:
    
    throwableSupplier - The supplier to supply an exception if this is an Err instance. Must not be null. The supplier must return a non-null result.
    
    Returns:
    
    The contained value.
    
    Throws:
    
    R - If this is an Err instance.
    
    R extends java.lang.Throwable
  - map
```
<U> Result<U,E> map(FunctionWithException<? super V,? extends U> mapper)
```
    Map the contained value if this is an Ok value. Otherwise return this.
    
    Type Parameters:
    
    U - The new value type.
    
    Parameters:
    
    mapper - The function to map the contained value into a new value. Must not be null. The function must return a non-null value.
    
    Returns:
    
    A result containing the mapped value if this is an Ok value. Otherwise this.
  - mapErr
```
<F> Result<V,F> mapErr(FunctionWithException<? super E,? extends F> mapper)
```
    Map the contained error if this is an Err value. Otherwise return this.
    
    Type Parameters:
    
    F - The new error type.
    
    Parameters:
    
    mapper - The function to map the contained error into a new error. Must not be null. The function must return a non-null error.
    
    Returns:
    
    A result containing the mapped error if this is an Err value. Otherwise this.
  - flatMap
```
<U> Result<U,E> flatMap(FunctionWithException<? super V,? extends Result<? extends U,? extends E>> mapper)
```
    FlatMap the contained value if this is an Ok value. Otherwise return this.
    
    Type Parameters:
    
    U - The new value type.
    
    Parameters:
    
    mapper - The function to flatmap the contained value into a new result. Must not be null. The function must return a non-null result.
    
    Returns:
    
    The flatmapped result if this is an Ok value. Otherwise this.
  - recover
```
Result<V,E> recover(FunctionWithException<? super E,? extends V> recover)
```
    Recover the contained error if this is an Err value. Otherwise return this.
    
    Parameters:
    
    recover - The function to recover the contained error into a new value. Must not be null. The function must return a non-null value.
    
    Returns:
    
    A result containing the new value if this is an Err value. Otherwise this.
  - accept
```
void accept(ConsumerWithException<? super V> ok,
            ConsumerWithException<? super E> err)
```
    Terminal function that processes the result or the error
    
    Parameters:
    
    ok - the consumer called when ok
    
    err - the consumer called when not ok
  - asError
```
<X> Result<X,E> asError()
```
  - unwrap
```
<X extends java.lang.Throwable> V unwrap(java.util.function.Function<E,X> constructor)
                                  throws X extends java.lang.Throwable
```
    Throws:
    
    X extends java.lang.Throwable

Interface Result<V,​E>

Method Summary

Method Detail

of

ok

err

err

isOk

isErr

value

error

unwrap

unwrap

orElse

orElseGet

orElseThrow

map

mapErr

flatMap

recover

accept

asError

unwrap

Interface Result<V,E>