SetOnce (milky-common 1.0.13 API)

java.lang.Object
- cn.sliew.milky.common.collect.SetOnce<T>

All Implemented Interfaces:

Cloneable
```
public final class SetOnce<T>
extends Object
implements Cloneable
```
A convenient class which offers a semi-immutable object wrapper implementation which allows one to set the value of an object exactly once, and retrieve it many times. If set(Object) is called more than once, SetOnce.AlreadySetException is thrown and the operation will fail.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class SetOnce.AlreadySetException
Thrown when set(Object) is called more than once.

Constructor Summary

Constructors
Constructor	Description
`SetOnce()`	A default constructor which does not set the internal object, and allows setting it by calling `set(Object)`.
`SetOnce(T obj)`	Creates a new instance with the internal object set to the given object.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`T`	`get()`	Returns the object set by `set(Object)`.
`void`	`set(T obj)`	Sets the given object.
`boolean`	`trySet(T obj)`	Sets the given object if none was set before.

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

- Constructor Detail
  - SetOnce
```
public SetOnce()
```
    A default constructor which does not set the internal object, and allows setting it by calling set(Object).
  - SetOnce
```
public SetOnce(T obj)
```
    Creates a new instance with the internal object set to the given object. Note that any calls to set(Object) afterwards will result in SetOnce.AlreadySetException
    
    Throws:
    
    SetOnce.AlreadySetException - if called more than once
    
    See Also:
    
    set(Object)
- Method Detail
  - set
```
public void set(T obj)
```
    Sets the given object. If the object has already been set, an exception is thrown.
  - trySet
```
public boolean trySet(T obj)
```
    Sets the given object if none was set before.
    
    Returns:
    
    true if object was set successfully, false otherwise
  - get
```
public T get()
```
    Returns the object set by set(Object).