Maybe (tensorics-core API)

java.lang.Object
- org.tensorics.core.util.Maybe<T>

Type Parameters:

T - the type to carry.
```
public class Maybe<T>
extends java.lang.Object
```
This utility class implements the concept of a "Maybe" or "Try" Optional. A Maybe<T> either carries a T or an exception that occurred when producing it.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Maybe.ThrowingConsumer<T>`
`static interface`	`Maybe.ThrowingFunction<I,R>`
`static interface`	`Maybe.ThrowingRunnable`
`static interface`	`Maybe.ThrowingSupplier<T>`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static Maybe<java.lang.Void>`	`attempt(Maybe.ThrowingRunnable runnable)` Construct a `Maybe`<Void> from the execution of a void function.
`static <T> Maybe<T>`	`attempt(Maybe.ThrowingSupplier<T> runnable)` Construct a `Maybe` from the execution of a function.
`boolean`	`equals(java.lang.Object obj)`
`java.util.Optional<java.lang.Throwable>`	`exception()` Returns the exception, if any.
`boolean`	`hasException()` Returns true if this Maybe is in an "unsuccessful" state, i.e.
`int`	`hashCode()`
`Maybe<java.lang.Void>`	`map(Maybe.ThrowingConsumer<T> function)` Apply a void function if this `Maybe` is in a "successful" state.
`<R> Maybe<R>`	`map(Maybe.ThrowingFunction<T,R> function)` Apply a transformation function if this `Maybe` is in a "successful" state.
`static <T> Maybe<T>`	`ofException(java.lang.Throwable exception)` Construct an "unsuccessful" `Maybe` containing an exception.
`static <T> Maybe<T>`	`ofValue(T value)` Construct a "successful" `Maybe` containing a value.
`static Maybe<java.lang.Void>`	`ofVoid()` Construct a "successful" `Maybe`<Void> containing a null value.
`java.util.Optional<T>`	`optionalValue()` Retrieve the value stored in this `Maybe` as an `Optional`.
`Maybe<java.lang.Void>`	`then(Maybe.ThrowingRunnable runnable)` Apply a void function if this `Maybe` is in a "successful" state.
`<R> Maybe<R>`	`then(Maybe.ThrowingSupplier<R> runnable)` Apply a function if this `Maybe` is in a "successful" state.
`void`	`throwOnException()` Throw the contained exception, wrapped in a `RuntimeException`, if any.
`java.lang.String`	`toString()`
`T`	`value()` Retrieve the value stored in this `Maybe`.

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

- Method Detail
  - ofException
```
public static <T> Maybe<T> ofException(java.lang.Throwable exception)
```
    Construct an "unsuccessful" Maybe containing an exception.
    
    Parameters:
    
    exception - the exception to wrap
    
    Returns:
    
    the unsuccessful Maybe object
    
    Throws:
    
    java.lang.NullPointerException - if the exception is null
  - ofValue
```
public static <T> Maybe<T> ofValue(T value)
```
    Construct a "successful" Maybe containing a value.
    
    Parameters:
    
    value - the value to wrap
    
    Returns:
    
    the successful Maybe object
    
    Throws:
    
    java.lang.NullPointerException - if the value is null
  - ofVoid
```
public static Maybe<java.lang.Void> ofVoid()
```
    Construct a "successful" Maybe<Void> containing a null value. This special Maybe objects represents a successful execution with no result (e.g. a void function). Note that ONLY Maybe<Void> is allowed to carry a null value.
    
    Returns:
    
    the successful Maybe<Void> object
  - exception
```
public java.util.Optional<java.lang.Throwable> exception()
```
    Returns the exception, if any.
    
    Returns:
    
    the contained exception, or Optional.empty() if none occurred.
  - hasException
```
public boolean hasException()
```
    Returns true if this Maybe is in an "unsuccessful" state, i.e. containing an exception.
    
    Returns:
    
    true if an exception is present, false otherwise
  - value
```
public T value()
```
    Retrieve the value stored in this Maybe. If an exception is stored, this method will re-throw it wrapped in a RuntimeException.
    
    Returns:
    
    the value
    
    Throws:
    
    java.lang.RuntimeException - if this Maybe objects contains an exception
  - optionalValue
```
public java.util.Optional<T> optionalValue()
```
    Retrieve the value stored in this Maybe as an Optional. If an exception is stored in this Maybe, the returned optional will be empty. For a "successful" Maybe<Void>, it will contain null.
    
    Returns:
    
    the value
    
    Throws:
    
    java.lang.RuntimeException - if this Maybe objects contains an exception
  - throwOnException
```
public void throwOnException()
```
    Throw the contained exception, wrapped in a RuntimeException, if any. If called on a "successful" Maybe, this method does nothing.
  - attempt
```
public static <T> Maybe<T> attempt(Maybe.ThrowingSupplier<T> runnable)
```
    Construct a Maybe from the execution of a function.
    
    Parameters:
    
    runnable - the function to run.
    
    Returns:
    
    A Maybe object containing either the return value of the function, or an exception of one occurred.
  - attempt
```
public static Maybe<java.lang.Void> attempt(Maybe.ThrowingRunnable runnable)
```
    Construct a Maybe<Void> from the execution of a void function.
    
    Parameters:
    
    runnable - the function to run.
    
    Returns:
    
    A successful Maybe<Void> if the function run successfully, or an exception of one occurred.
  - map
```
public <R> Maybe<R> map(Maybe.ThrowingFunction<T,R> function)
```
    Apply a transformation function if this Maybe is in a "successful" state. Pass through the exception in case it is in an "unsuccessful" state. If the transformation function throws, the exception is returned wrapped in an "unsuccessful" Maybe.
    
    Parameters:
    
    function - the function to apply
    
    Returns:
    
    A successful Maybe the new value if the transformation succeeds. An unsuccessful Maybe otherwise.
  - map
```
public Maybe<java.lang.Void> map(Maybe.ThrowingConsumer<T> function)
```
    Apply a void function if this Maybe is in a "successful" state. Pass through the exception in case it is in an "unsuccessful" state. If the transformation function throws, the exception is returned wrapped in an "unsuccessful" Maybe. If it succeeds, return an empty Maybe<Void>.
    
    Parameters:
    
    function - the function to apply
    
    Returns:
    
    A successful Maybe<Void> if the function is executed and succeeds. An unsuccessful Maybe otherwise.
  - then
```
public <R> Maybe<R> then(Maybe.ThrowingSupplier<R> runnable)
```
    Apply a function if this Maybe is in a "successful" state. Pass through the exception in case it is in an "unsuccessful" state. The function does not get the value of the Maybe passed as parameter, which is useful e.g. for chaining Maybe<Void>. If the function succeeds, its result is returned as a successful Maybe.
    
    Parameters:
    
    runnable - the function to apply
    
    Returns:
    
    A successful Maybe wrapping the return value if the function is executed and succeeds. An unsuccessful Maybe otherwise.
  - then
```
public Maybe<java.lang.Void> then(Maybe.ThrowingRunnable runnable)
```
    Apply a void function if this Maybe is in a "successful" state. Pass through the exception in case it is in an "unsuccessful" state. The function does not get the value of the Maybe passed as parameter, which is useful e.g. for chaining Maybe<Void>. If the function succeeds, a successful empty Maybe<Void> is returned.
    
    Parameters:
    
    runnable - the function to apply
    
    Returns:
    
    A successful Maybe<Void> it the function is executed and succeeds. An unsuccessful Maybe otherwise.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Overrides:
    
    equals in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class Maybe<T>

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

ofException

ofValue

ofVoid

exception

hasException

value

optionalValue

throwOnException

attempt

attempt

map

map

then

then

hashCode

equals

toString