[jira] [Comment Edited] (LANG-1611) Add an initializer which can compare and re-initialize value

["Andrey Fadeev (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LANG-1611?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17264566#comment-17264566 ] 

Andrey Fadeev edited comment on LANG-1611 at 1/14/21, 3:15 AM:
---------------------------------------------------------------

If there's only one token for an Initializer instance, why not trigger initialization simply by calling the get() method, like in the {{AtomicInitializer but using check for expiration instead of a }}null?

 
{quote}{color:#bbb529}@Override
{color}{color:#cc7832}public {color}{color:#507874}T {color}{color:#ffc66d}get{color}() {color:#cc7832}throws {color}ConcurrentException {
 {color:#507874}T {color}result = {color:#9876aa}reference{color}.get(){color:#cc7832};
{color}{color:#cc7832}
{color}{color:#cc7832} if {color}(result == {color:#cc7832}null{color}) {
 result = initialize(){color:#cc7832};
{color}{color:#cc7832} if {color}(!{color:#9876aa}reference{color}.compareAndSet({color:#cc7832}null, {color}result)) {
 {color:#808080}// another thread has initialized the reference
{color} result = {color:#9876aa}reference{color}.get(){color:#cc7832};
{color} }
 }

 {color:#cc7832}return {color}result{color:#cc7832};
{color}}
{quote}


was (Author: andrey fadeev):
If there's only one token for an {{Initializer}} instance, why not use the {{AtomicInitializer}} and trigger initialization when the token expires simply by calling the {{initialize()}} method?

> Add an initializer which can compare and re-initialize value
> ------------------------------------------------------------
>
>                 Key: LANG-1611
>                 URL: https://issues.apache.org/jira/browse/LANG-1611
>             Project: Commons Lang
>          Issue Type: New Feature
>          Components: lang.concurrent.*
>            Reporter: Franz Wong
>            Priority: Minor
>
> I would like to have a new class which is similar to {{AtomicSafeInitializer}}. But we can compare and re-initialize the value.
> The use case is to refresh access token (e.g. OAuth) when it expires. Multiple threads tries to refresh the same token at the same time, but there should be only one thread to do it, in addition, only the thread which passes the expired token can trigger the initialization.



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