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Date: Mon, 22 May 2017 13:27:04 +0000 (UTC)
From: "John Mark (JIRA)" <jira@apache.org>
To: issues@commons.apache.org
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Subject: [jira] [Commented] (COLLECTIONS-602) Improve efficiency of
 DefaultedMap.get
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archived-at: Mon, 22 May 2017 13:27:13 -0000


    [ https://issues.apache.org/jira/browse/COLLECTIONS-602?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16019576#comment-16019576 ] 

John Mark commented on COLLECTIONS-602:
---------------------------------------

Yes, that is what I was looking for, thanks.

I am attaching a patch to this ticket.


> Improve efficiency of DefaultedMap.get
> --------------------------------------
>
>                 Key: COLLECTIONS-602
>                 URL: https://issues.apache.org/jira/browse/COLLECTIONS-602
>             Project: Commons Collections
>          Issue Type: Bug
>            Reporter: John Mark
>              Labels: help-wanted
>         Attachments: COLLECTIONS-602.patch
>
>
> The current implementation of {{org.apache.commons.collections4.map.DefaultedMap.get()}} is inefficient since it always require two map lookups. There is no need to check map.containsKey() every time. I would suggest implementing this method similar to the way that Java 8 does with {{Map.getOrDefault()}}. My proposed implementation would be something like this:
> {code}
> public V get(final Object key) {
>     V v;
>     return ((v = map.get(key) != null) || map.containsKey(key)) ? v : value.transform((K) key);
> }
> {code}
> It can be further optimized to not even call map.containsKey() if map is known to not contain null values.


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