ValueObserver

Type Parameters:

T - the type of the value

All Superinterfaces:

EventObserver<T>, Supplier<T>

All Known Subinterfaces:

ComponentValue<T,C>, PropertyValue<T>, State, State.Combination, StateObserver, StringValue<T>, Value<T>, ValueSet<T>

All Known Implementing Classes:

AbstractComponentValue, AbstractTextComponentValue, AbstractValue
```
public interface ValueObserver<T>
extends EventObserver<T>, Supplier<T>
```
A read only value observer

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default boolean`	`equalTo(T value)`	Returns true if the underlying value is equal to the given one.
`default boolean`	`isNotNull()`
`default boolean`	`isNull()`
`boolean`	`isNullable()`	If false then get() is guaranteed to never return null.
`default Optional<T>`	`toOptional()`

Methods inherited from interface is.codion.common.event.EventObserver
addDataListener, addListener, removeDataListener, removeListener

Methods inherited from interface java.util.function.Supplier
get

- Method Detail
  - toOptional
```
default Optional<T> toOptional()
```
    Returns:
    
    an Optional wrapping this value.
  - isNull
```
default boolean isNull()
```
    Returns:
    
    true if the underlying value is null.
  - isNotNull
```
default boolean isNotNull()
```
    Returns:
    
    true if the underlying value is not null.
  - isNullable
```
boolean isNullable()
```
    If false then get() is guaranteed to never return null.
    
    Returns:
    
    true if this value can be null
  - equalTo
```
default boolean equalTo(T value)
```
    Returns true if the underlying value is equal to the given one. Note that null == null.
    
    Parameters:
    
    value - the value
    
    Returns:
    
    true if the underlying value is equal to the given one