[jira] [Commented] (CONFIGURATION-442) SubsetConfiguration does not properly list attributes when a delimiter is set

["Oliver Heger (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CONFIGURATION-442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016484#comment-13016484 ] 

Oliver Heger commented on CONFIGURATION-442:
--------------------------------------------

Is there a special reason why you instantiate the {{SubsetConfiguration}} directly rather than calling the {{subset()}} method of the configuration?

{{HirachicalConfiguration}} overrides {{subset()}} to construct a specialized hierarchical subset configuration. This configuration should return a correct iterator for its keys.

You are probably right that {{SubsetConfiguration}} does not play well with a hierarchical configuration, but this is the reason why {{HierarchicalConfiguration}} provides an alternative implementation of the {{subset()}} method. So the intended usage scenario is to call {{subset()}} on the target configuration rather than creating the {{SubsetConfiguration}} manually.

Would this solve your problem?

> SubsetConfiguration does not properly list attributes when a delimiter is set
> -----------------------------------------------------------------------------
>
>                 Key: CONFIGURATION-442
>                 URL: https://issues.apache.org/jira/browse/CONFIGURATION-442
>             Project: Commons Configuration
>          Issue Type: Bug
>    Affects Versions: 1.6
>         Environment: all
>            Reporter: Fabien Nisol
>
> imagine a XmlConfiguration like this:
> {code}
> <properties>
>   <prop1>
>     <prop2>
>       <prop
>          attr1="attr1"
>          attr2="attr2"/>
>     </prop2>
>   </prop1>
> </properties>
> {code}
> If subset get instanciated to the end of the hierarchy, with a specific delimiter, getKeys() won't return the correct keys:
> {code}
> ...
> XMLConfiguration config = new XMLConfiguration("test/test.xml");
> Configuration subset = new SubsetConfiguration(config,"prop1.prop2.prop",".");
> ConfigurationUtils.dump(subset, System.err);
> ...
> {code}
> gives the result:
> {code}
> @attr1]=null
> @attr2]=null
> {code}
> it should give the result
> {code}
> [@attr1]=attr1
> [@attr2]=attr2
> {code}
> The wrong dump is a side effect of the wrong implementation of the _getChildKey_ method of SubsetConfiguration
> {code}
>  /**
>      * Return the key in the subset configuration associated to the specified
>      * key in the parent configuration.
>      *
>      * @param key The key in the parent configuration.
>      * @return the key in the context of this subset configuration
>      */
>     protected String getChildKey(String key)
>     {
>         if (!key.startsWith(prefix))
>         {
>             throw new IllegalArgumentException("The parent key '" + key + "' is not in the subset.");
>         }
>         else
>         {
>             String modifiedKey = null;
>             if (key.length() == prefix.length())
>             {
>                 modifiedKey = "";
>             }
>             else
>             {
>                 int i = prefix.length() + (delimiter != null ? delimiter.length() : 0);
>                 modifiedKey = key.substring(i);
>             }
>             return modifiedKey;
>         }
>     }
> {code}
> In this code, the _else_ part is wrong. In a hierarchical configuration, the attribute delimiter is '[' and is removed here.
> I think a more correct code would be :
> {code}
> /**
>      * Return the key in the subset configuration associated to the specified
>      * key in the parent configuration.
>      *
>      * @param key The key in the parent configuration.
>      * @return the key in the context of this subset configuration
>      */
>     protected String getChildKey(String key)
>     {
>         if (!key.startsWith(prefix))
>         {
>             throw new IllegalArgumentException("The parent key '" + key + "' is not in the subset.");
>         }
>         else
>         {
>             String modifiedKey = null;
>             if (key.length() == prefix.length())
>             {
>                 modifiedKey = "";
>             }
>             else
>             {
>                 modifiedKey = key.substring(prefix.length());
>                 if(delimiter!=null && modifiedKey.startsWith(delimiter))
>                 {
>                     modifiedKey=modifiedKey.substring(delimiter.length());
>                 }
>             }
>             return modifiedKey;
>         }
>     }
> {code}

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