<div dir="ltr">I am glad my feedback was helpful and sparkled such a great discussion. I would like to put 2 cents more, looking for these to be helpful.<div><br></div><div>My main concern with "orElse" is that most of the time (at least for my how I would use this API in my job) most of the time I need a reliable way to set the constant and use that particular constant along the life cycle of the class, **not** declaring an alternative local variable in replacement because most of the time there is no good "burned in the code" alternatives that I could use . The use cases I have for this API are usually about deferred initialization of values that often require some time costly operation, some of those may involve calls to external services (IO operations) thus having a "burned" constant in these cases is not useful. Instead I propose a "computeIfAbsent" (I am not against orElse naming) method that allows for alternative downstream conditional initialization of the Lazy constant.</div><div><br></div><div><div style="background-color:rgb(30,30,30);color:rgb(212,212,212)"><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"><br><span style="color:rgb(71,162,237)">private class </span><span style="color:rgb(71,204,177)">Bar</span>{<br> LazyCosntan<Weather> <span style="color:rgb(140,215,255)">weatherUrl </span>= LazyCosntant.of(this<span style="font-size:9.8pt">::</span><span style="font-size:9.8pt;color:rgb(230,230,170)">checkAndGetWeatherUrl</span>);</pre><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"> <br> <span style="color:rgb(71,162,237)">public </span><span style="color:rgb(230,230,170)">Bar</span>(){}<br> <br> <span style="color:rgb(71,162,237)">private </span><span style="color:rgb(71,204,177)">String </span><span style="color:rgb(230,230,170)">checkAndGetWeatherUrl</span>(){<br> <span style="color:rgb(204,133,198)">return </span><span style="color:rgb(71,204,177)">Executors</span>.<span style="color:rgb(255,198,109);font-style:italic">newVirtualThreadPerTaskExecutor</span>()<br> .submit(() -> <span style="color:rgb(105,152,86)">/*Some query to check if the weather server is up*/</span>);<br> }<br> <br> <span style="color:rgb(71,162,237)">private </span><span style="color:rgb(71,204,177)">String </span><span style="color:rgb(230,230,170)">checkAndGetAltWeatherUrl</span>(){<br> <span style="color:rgb(204,133,198)">return </span><span style="color:rgb(71,204,177)">Executors</span>.<span style="color:rgb(255,198,109);font-style:italic">newVirtualThreadPerTaskExecutor</span>()<br> .submit(() -> <span style="color:rgb(105,152,86)">/*Some query to check if the alt weather server is up*/</span>);<br> }<br> <br> <span style="color:rgb(71,162,237)">public </span>Weather <span style="color:rgb(230,230,170)">getWeather</span>(){<br> <br> var url = <span style="color:rgb(140,215,255)">weatherUrl</span>.computeIfAbsent(<span style="color:rgb(71,162,237)">this</span>::<span style="color:rgb(230,230,170)">checkAndGetAltWeatherUrl</span>).get();</pre><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"> <span style="color:rgb(105,152,86)">// logic to get the weather here using the lazy constants//<br></span><span style="color:rgb(105,152,86)"> </span>}</pre><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"> public void <span style="font-size:9.8pt;color:rgb(230,230,170)">sendWeather</span><span style="font-size:9.8pt">(){</span><br></pre><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"><span style="font-size:9.8pt"> </span>var url = <span style="font-size:9.8pt;color:rgb(140,215,255)">weatherUrl</span><span style="font-size:9.8pt">.computeIfAbsent(</span><span style="font-size:9.8pt;color:rgb(71,162,237)">this</span><span style="font-size:9.8pt">::</span><span style="font-size:9.8pt;color:rgb(230,230,170)">checkAndGetAltWeatherUrl</span><span style="font-size:9.8pt">).get();</span></pre><div><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"> <span style="color:rgb(71,204,177)">Executors</span>.<span style="color:rgb(255,198,109);font-style:italic">newVirtualThreadPerTaskExecutor</span>()<br> .submit(() -> <span style="color:rgb(105,152,86)">/*Send the weather url to somewhere else* using weatherUrl*/</span>);<br> }</pre></div><pre style="font-family:"JetBrains Mono",monospace;font-size:9.8pt"><br>}</pre></div></div><div><br></div><div>This pattern is very common, either for a trivial weather or to check or a conf and alternatives in case the regular one is not available (for example a conf file that may be missing and one may set a method that downloads it from a remote server first in case it is absent)</div><div><br></div><div>So for me the issue is not the concept of "orElse" but how the current implementation returns me an alternative value instead of SETTING an alternative value in case the regular attempt fails or hasn't been called still because the program followed an alternative path before the obvious regular initialization path. If the orElse (or any other name that fits) changes the behaviour to set a value instead of returning something it would be the best approach IMHO.</div><div><br></div><div><br></div><div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">El mar, 9 dic 2025 a la(s) 9:13 a.m., Anatoly Kupriyanov (<a href="mailto:kan.izh@gmail.com">kan.izh@gmail.com</a>) escribió:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>My idea is not an optional <i>interface</i>, but an interface for something which is convertible to the Optional <i>type</i>. In other words, neither the LazyConstant nor to ScopedVariable <b>is not</b> an optional itself, but could be converted to it uniformly.</div><div>Something like this:</div><div><span style="font-family:monospace"><br></span></div><div><span style="font-family:monospace">interface Optionable<T> {// need to think about the better naming!</span></div><div><span style="font-family:monospace"> T orElse(T other);</span></div><div><span style="font-family:monospace"><br></span></div><div><span style="font-family:monospace"> // and maybe even:</span></div><div><span style="font-family:monospace"> default Optional<T> asOptional() {</span></div><div><span style="font-family:monospace"> return Optional.ofNullable(this.orElse(null));</span></div><div><span style="font-family:monospace"> };</span></div><div><span style="font-family:monospace">}</span></div><div><br></div><div>and then LazyConstant, ScopedVariable, etc could just implement the interface to unify on the notion of "return a user-provided value <br>
if some condition isn't met". Sounds like a decent path to abolish nulls.</div><div><br></div><div>But I feel I am overthinking this...</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 9 Dec 2025 at 13:35, Red IO <<a href="mailto:redio.development@gmail.com" target="_blank">redio.development@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">I initially thought I agree with your statement that orElse is a common pattern in the jdk. But then I failed to come up with a second example. I then searched the jdk github repo for the method. And I only found Optional and it's specializations and ClassHierarchyResolver.<div dir="auto">So I would suggest yes, it's an often used method ... of the Optional class. Not many apis seem to expose it. The case of exposing an accessor that returns an Optional on the other hand is incredibly common across the jdk. This is exactly the case Optional was designed for. In this sense Optional is the "Interface" you are suggesting. </div><div dir="auto"><br></div><div dir="auto">My main argument against reusing orElse here is that the context is a completely different one. </div><div dir="auto">An Optional orElse method is a pure function that always returns the same value. It signals that the value is not there.</div><div dir="auto">LazyConstant is different in this regard. The LazyConstant orElse is not pure at all. It depends on rather someone else already initialized the value or not. It signals that the value is not there YET.</div><div dir="auto"><br></div><div dir="auto">Great regards </div><div dir="auto">RedIODev </div><div dir="auto"><br></div><div dir="auto"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Dec 9, 2025, 13:51 Anatoly Kupriyanov <<a href="mailto:kan.izh@gmail.com" target="_blank">kan.izh@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Right, the ScopedValue is another good example I've forgotten. In that case I am even more inclined to keep the `orElse` as it looks like a repeating pattern across JDK libraries. Consistency is the way to go!</div><div>And maybe even consider having a new interface for the method to make this pattern explicit?..</div><div><br></div><div>I am glad that `orElseSet` is removed, the side-effecting is bad; also in other parts of JDK we already have `computeIfAbsent` for the same idea. I did not hear about it, and yeah, sounds like the source of this confusion.</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 9 Dec 2025 at 12:05, Maurizio Cimadamore <<a href="mailto:maurizio.cimadamore@oracle.com" rel="noreferrer" target="_blank">maurizio.cimadamore@oracle.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
On 09/12/2025 11:59, Anatoly Kupriyanov wrote:<br>
> To be honest, I don't really see why this method causes such confusion.<br>
<br>
In part I agree. E.g. when we added this, what we had in mind was just<br>
<br>
<a href="https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/ScopedValue.html#orElse(T)" rel="noreferrer noreferrer" target="_blank">https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/ScopedValue.html#orElse(T)</a><br>
<br>
E.g. other APIs have `orElse` method that return a user-provided value <br>
if some condition isn't met.<br>
<br>
I believe the problem we're discussing here is likely also related to <br>
the fact that the API used to have a side-effecting `orElseSet`, which <br>
is now removed, and I wonder if, because of that, folks are reading too <br>
much into what orElse does?<br>
<br>
Maurizio<br>
<br>
</blockquote></div><div><br clear="all"></div><br><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature">WBR, Anatoly.</div>
</blockquote></div>
</blockquote></div><div><br clear="all"></div><br><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature">WBR, Anatoly.</div>
</blockquote></div>