[jira] [Created] (IGNITE-15409) Configuration registry: register listener with any placeholder on NamedConfigurationTree

["Alexander Lapin (Jira)" <ji...@apache.org>]

Alexander Lapin created IGNITE-15409:
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             Summary: Configuration registry: register listener with any placeholder on NamedConfigurationTree
                 Key: IGNITE-15409
                 URL: https://issues.apache.org/jira/browse/IGNITE-15409
             Project: Ignite
          Issue Type: Improvement
            Reporter: Alexander Lapin
            Assignee: Ivan Bessonov


Ability to add listeners with "any()" placeholder will ease the logic of registering ones.

Let's say that we want to listen to a changes of a column type within any column of any table. Now the only option is to register type listeners from within column listeners within table listeners:

 
{code:java}
clusterCfgMgr.configurationRegistry().getConfiguration(TablesConfiguration.KEY).tables().listenElements(
    new ConfigurationNamedListListener<TableView>() {
    @Override
    public @NotNull CompletableFuture<?> onCreate(@NotNull ConfigurationNotificationEvent<TableView> tblCtx) {
        clusterCfgMgr.configurationRegistry().getConfiguration(TablesConfiguration.KEY).tables().
            get(tblCtx.newValue().name()).columns().listenElements(
                new ConfigurationNamedListListener<ColumnView>() {
            @Override public @NotNull CompletableFuture<?> onCreate(
                @NotNull ConfigurationNotificationEvent<ColumnView> columnCtx) {
                clusterCfgMgr.configurationRegistry().getConfiguration(TablesConfiguration.KEY).tables().
                    get(tblCtx.newValue().name()).columns().get(columnCtx.newValue().name()).listen((typeCtx) -> null);
                return CompletableFuture.completedFuture(null);
            }
        });
        return CompletableFuture.completedFuture(null);
    }

{code}
With any placeholder it will look like much simpler:
{code:java}
clusterCfgMgr.configurationRegistry().getConfiguration(TablesConfiguration.KEY).tables().any().columns().
    any().type().listen(ctx -> null);
{code}
Besides obvious there are at least two important points here:
 * It should be possible to retrieve full context/"full configuration locator" from the listener's context. In this particular case _type().listen(ctx -> null)_ should provide context of the table and the column that were changed.
 * It should be possible to remove such "any" listeners

 

 



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