[jira] [Commented] (CARBONDATA-299) 4. Add dictionary generator interfaces and give implementation for pre created dictionary.

[Akash R Nilugal (Jira)]

    [ https://issues.apache.org/jira/browse/CARBONDATA-299?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15574306#comment-15574306 ]

ASF GitHub Bot commented on CARBONDATA-299:
-------------------------------------------

Github user jackylk commented on a diff in the pull request:

    https://github.com/apache/incubator-carbondata/pull/236#discussion_r83360819
 
    --- Diff: processing/src/main/java/org/apache/carbondata/processing/newflow/dictionary/InMemBiDictionary.java ---
    @@ -0,0 +1,85 @@
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    +
    +package org.apache.carbondata.processing.newflow.dictionary;
    +
    +import java.util.Map;
    +
    +import org.apache.carbondata.core.devapi.DictionaryGenerator;
    +import org.apache.carbondata.core.devapi.GeneratingBiDictionary;
    +
    +import com.google.common.collect.BiMap;
    +import com.google.common.collect.HashBiMap;
    +
    +public class InMemBiDictionary<K, V> extends GeneratingBiDictionary<K, V> {
    --- End diff --
   
    This `InMemBiDictionary` is for one column, when it comes to cache, I think the cached object is 'BiDictionary`. Since the cache provides KV API, so we need a TableDictionary to make use of the cache. I am thinking to add another class for table dictionary, like
    ```
    CachedTableDictionary tableDict = new CachedTableDictionary(tableName)
    key = tableDict.getOrGenerateKey(columnName, value)
    ```
    Inside `CachedTableDictionary`, it will maintain a cache of `HashMap<columnName, BiDictionary>`
    I am thinking to use [Cache](https://github.com/google/guava/wiki/CachesExplained) from Guava also

> 4. Add dictionary generator interfaces and give implementation for pre created dictionary.
> ------------------------------------------------------------------------------------------
>
>                 Key: CARBONDATA-299
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-299
>             Project: CarbonData
>          Issue Type: Sub-task
>            Reporter: Ravindra Pesala
>            Assignee: Jacky Li
>             Fix For: 0.2.0-incubating
>
>
> Add dictionary generator interfaces and give implementation for pre-created dictionary(which is generated separetly).

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