| java.lang.Object
 com.tc.util.concurrent.SetOnceRef
| SetOnceRef | | final public class SetOnceRef (Code) | | An object reference holder class in which the reference can only be set once. This might be useful for a member
variable that you'd like to make final, but that you aren't able to set within a constructor. I suppose this class is
a lot like TCFuture, but this class doesn't offer methods to wait for a value to set. The use case for this class has
nothing to do with communication/synchronization between threads. This class is meant to make sure you can't change a
reference once it's been set (ie. it provides a reference member variable that behaves like it was marked "final" and
won't let anyone read it until it has been set)
author:
teck |
| SetOnceRef | | public SetOnceRef()(Code) | | Create a new set() 'able instance This instance will not permitted to contain a null
reference
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| SetOnceRef | | public SetOnceRef(Object ref)(Code) | | Create and immediately set() to the given reference. This instance will not permitted to
contain a null reference
Parameters:
ref - The reference to hold
throws:
IllegalArgumentException - If the reference to hold is null |
| SetOnceRef | | public SetOnceRef(Object ref, boolean allowNull)(Code) | | Create and immediately set() to the given refernce
Parameters:
ref - the reference to hold
Parameters:
allowNull - true to allow nulls to be stored in this instance
throws:
IllegalArgumentException - if allowNull is true and the given reference is null |
| SetOnceRef | | public SetOnceRef(boolean allowNull)(Code) | | Create a new set() 'able instance
Parameters:
allowNull - true to allow this instance to hold the value null |
| allowsNull | | public boolean allowsNull()(Code) | | Can null ever be the value of this reference
true if null is allowed, false otherwise |
| get | | public Object get()(Code) | | Get the reference value contained in this instance
the reference, may be null if this instance allow nulls (see allowNull
throws:
IllegalStateException - if a valid reference value has not yet been set |
| isSet | | public boolean isSet()(Code) | | Has someone set the reference yet
true iff the reference has been set |
| set | | public void set(Object ref)(Code) | | Attmept to set the reference to the given value
Parameters:
ref - the reference to set in this instance
throws:
IllegalStateException - if the reference has already been set by another thread
throws:
IllegalArgumentException - if the given reference is null and this instance does not allow the null value |
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