RFR: 8307652: sealed class hierarchy graph doesn't distinguish non-sealed classes

[Chen Liang]

On Mon, 15 May 2023 06:46:28 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> `@sealedGraph` had a mechanism to render non-sealed classes differently, but it's useless because the graph nodes are not bordered. This patch converts the non-sealed classes to be rendered in italics instead.
>> 
>> An example of `ConstantDesc`, which has a sealed hierarchy except `DynamicConstantDesc`:
>> JDK 20:
>> ![image](https://user-images.githubusercontent.com/7806504/236991678-e30c181a-cb1f-407a-b3e0-f648fe2df788.png)
>> 
>> This patch:
>> ![image](https://github.com/openjdk/jdk/assets/7806504/4fb8ec10-4f10-4902-8b9d-107b3644b2cf)
>
> Thanks for this improvement suggestion. Indicating "openness" is certainly important. I was playing around with various ways of expressing it and came up with this:
> 
> ![image](https://github.com/openjdk/jdk/assets/7457876/3f5204b5-7dd7-47ee-9df4-397c5b69f0d4)
> 
> What is your opinion on it? It might be slightly more intuitive? We could even do this:
> 
> ![image](https://github.com/openjdk/jdk/assets/7457876/32e2542f-ef81-4523-a658-d0a39da13ea8)
> 
> 
> 
> Here is the code:
> 
> 
> 
> digraph G {
> 
>  shape="none"
>  rankdir = "BT"
>  
>  ClassDesc -> ConstantDesc
>  MethodHandleDesc -> ConstantDesc
>  DirectMethodHandleDesc -> MethodHandleDesc
>  DynamicConstantDesc -> ConstantDesc
>  Float -> ConstantDesc
>  Hidden1 -> DynamicConstantDesc [style="dashed"]
>  
>  Hidden1 [label="<any>"]
>  
>   ClassDesc [shape=none];
>   ConstantDesc [shape=none];
>   MethodHandleDesc [shape=none];
>   DynamicConstantDesc [shape=none];
>   DirectMethodHandleDesc [shape=none];
>   Float [shape=none];
>   Hidden1 [shape=none];
> }

@minborg Done. I've made the `<any>` in italics and its hover label is "Non-sealed Hierarchy". Example images of ConstantDesc and CallSite:
![image](https://github.com/openjdk/jdk/assets/7806504/f8e83eee-68b4-4a1e-9353-9c5ba5f453ee)
![image](https://github.com/openjdk/jdk/assets/7806504/f98dca5d-0fa9-4fa6-a680-df6c7b690524)

In addition, the copyright year is updated to reflect the correct creation date of this taglet (2022 instead of 2017)

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PR Comment: https://git.openjdk.org/jdk/pull/13877#issuecomment-1550071543