[GORA-665] - Add support for the Ignite datastore in GoraExplorer

[mgov88]

To add support for Apache Ignite in Gora Explorer the mapping XML must be read from gora.mapping in the same way as is implemented in the Kudu datastore.

[carlosrmng]

LGTM

[alfonsonishikawa]

@mgov88 I find we will need the metadata analyzer for Ignite too to have fully support of the features related to GoraExplorer.
Thank you!

[mgov88]

@alfonsonishikawa Hi, I took a look of HBase metadata analyzer https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/store/HBaseStoreMetadataAnalyzer.java I there are two methods to be implemented:
getTablesNames and getTableInfo.

getTablesNames is just a list of the tables
and getTableInfo is a list of the columns of a table

is it correct?

[alfonsonishikawa]

@alfonsonishikawa Hi, I took a look of HBase metadata analyzer https://github.com/apache/gora/blob/master/gora-hbase/src/main/java/org/apache/gora/hbase/store/HBaseStoreMetadataAnalyzer.java I there are two methods to be implemented:
getTablesNames and getTableInfo.

getTablesNames is just a list of the tables
and getTableInfo is a list of the columns of a table

is it correct?

It is correct but that is specific for HBase.

The first method, getTablesNames is needed for the type of mapping HBase has in the tag <table>. The signature for this method returns List<String> because I expected all datastores to have some "table" defined in their mappings.

The second method, getTableInfo returns specific data of the table and for HBase is an instance of HBaseTableMetadata, so in Ignite should be something like IgniteTableMetadata. The class IgniteTableMetadata that you have to create should have the needed information you can recover from the native store to help creating the mapping for that table.

The rule of thumb is that IgniteTableMetadata should return metadata about a table in Ignite. In the case of HBase are things called "Column Families", but that is absolutely related to HBase, not Ignite.

It could be, columns and types of each column, for example. Or columns, type, sizes, etc...
As I see from https://github.com/apache/gora/blob/master/gora-ignite/src/test/resources/gora-ignite-mapping.xml it looks Ignite needs the column name and it's type. So, that should be the minimum metadata returned in a (still not implemented) IgniteTableMetadata.java

[alfonsonishikawa]

Oh! And the primary key!

[mgov88]

@alfonsonishikawa I developed the Metadata Analyzer feature and a test, I had to update the ignite version, I can not find the schema information of the tables in the older version.

[alfonsonishikawa]

Merged to master. Thank you, @mgov88 !

[alfonsonishikawa]

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