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13.22. Object Translator

13.22.1. Object Translator

The Object translator is a bridge for reading Java objects from external sources, such as JBoss Data Grid (infinispan-cache) or Map Cache, and delivering them to the engine for processing. To assist in providing that bridge, the OBJECTTABLE function ( Section 3.6.11, “Nested Tables: OBJECTTABLE”) must be used to transform the Java object into rows and columns.
These are the types of object translators:
  • map-cache - supports a local cache that is of type Map and using Key searching. This translator is implemented by the org.teiid.translator.object.ObjectExecutionFactory class.

  • Important

    The ability to use Lucene to search a JDG cache from within the infinispan-cache translator has been deprecated. This is because the JDG DSL query language provides most of the features that match SQL querying. Therefore, there is no need to support two underlying querying options.
    infinispan-cache - supports JBoss Data Grid using either Key searching (for objects that are not annotated) or Hibernate/Lucene searching. This translator is implemented by the org.teiid.translator.object.infinispan.InfinispanExecutionFactory class which extends the org.teiid.translator.object.ObjectExecutionFactory class.

Note

See the JBoss Data Grid resource adapter for this translator. It can be configured to lookup the cache container via JNDI or created (i.e., ConfigurationFileName or RemoteServerList). Also see the Red Hat JBoss Data Virtualization Administration and Configuration Guide for more configuration information.

13.22.2. Object Translator: Execution Properties

The following execution properties are relevant to translating from JBoss Data Grid.

Table 13.15. Execution Properties

Name
Description
Required
Default
SupportsLuceneSearching
Setting to true assumes your objects are annotated and Hibernate/Lucene will be used to search the cache
N
false

13.22.3. Object Translator: Supported Capabilities

The following are the connector capabilities when Key Searching is used:
  • SELECT command
  • CompareCriteria - only EQ
  • InCriteria
The following are the connector capabilities when Hibernate/Lucene Searching is enabled:
  • SELECT command
  • CompareCriteria - EQ, NE, LT, GT, etc.
  • InCriteria
  • OrCriteria
  • And/Or Criteria
  • Like Criteria
  • INSERT, UPDATE, DELETE

13.22.4. Object Translator: Usage

Retrieve objects from a cache and transform into rows and columns.
  • The primary object returned by the cache should have a name in source of 'this'. All other columns will have their name in source (which defaults to the column name) interpreted as the path to the column value from the primary object.
  • All columns that are not the primary key nor covered by a lucene index should be marked as SEARCHABLE 'Unsearchable'.

13.22.5. Object Translator Example

The following is an example of a key search. It uses a dynamic vdb to define the physical source and views using DDL. It uses a TeamObject class, shown below, with a teamName field that is used as its cache key and a String list of players. 
public class TeamObject {

   private String teamName;
   private List<String> players = new ArrayList<String>();

   public String getTeamName() {
      return teamName;
   }

   public void setTeamName(String teamName) {
           this.teamName = teamName;
   }

   public List<String> getPlayers() {
           return players;
   }

}
Notice the use of the [OBJECTABLE|TEIID:OBJECTABLE] function to parse the object from Team and transform into rows and column. This metadata could also be defined by using Teiid Designer. 
<vdb name="team" version="1">
    <property name="UseConnectorMetadata" value="cached" />
    <model name="Team" visible="false">
        <source name="objsource" translator-name="infinispan1" connection-jndi-name="java:infinispan-jndi"/>
        <metadata type="DDL"><![CDATA[

            CREATE FOREIGN TABLE Team (
                TeamObject Object OPTIONS (NAMEINSOURCE 'this', SEARCHABLE 'Unsearchable'),
                teamName varchar(255) PRIMARY KEY)
              OPTIONS (NAMEINSOURCE 'teams');

         ]]> </metadata>
    </model>
    <model name="TeamView" type="VIRTUAL">
         <metadata type="DDL"><![CDATA[
             CREATE VIEW Players (
                  TeamName varchar(255) PRIMARY KEY,
                  PlayerName varchar(255)
             )
             AS
             SELECT t.TeamName, y.Name FROM Team as T,
                   OBJECTTABLE('m.players' PASSING T.TeamObject as m COLUMNS Name string 'teiid_row') as y;

        ]]> </metadata>
    </model>

    <translator name="infinispan1" type="infinispan-cache">
        <property name="SupportsLuceneSearching" value="true"/>
    </translator>
</vdb>