JBoss Community Archive (Read Only)

Teiid 8.12

Delegating Translators

You may create a delegating translator by extending the  org.teiid.translator.BaseDelegatingExecutionFactory . Once your classes are then packaged as a custom translator, you will be able to wire another translator instance into your delegating translator at runtime in order to intercept all of the calls to the delegate. This base class does not provide any functionality on its own, other than delegation.

Execution Properties  





Translator instance name to delegate to


Lets say you are currently using "oracle" translator in your VDB, you want to intercept the calls going through this translator, then you first write a custom delegating translator like

@Translator(name="interceptor", description="interceptor")
public class InterceptorExecutionFactory extends org.teiid.translator.BaseDelegatingExecutionFactory{
    public void getMetadata(MetadataFactory metadataFactory, C conn) throws TranslatorException {
        // do intercepting code here..

        // If you want call the original delegate, do not call if do not need to.
        // but if you did not call the delegate fullfill the method contract
        super.getMetadata(metadataFactory, conn);

        // do more intercepting code here..

Now deploy this translator in Teiid engine. Then in your -vdb.xml or .vdb file define like below.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vdb name="myvdb" version="1">

    <model name="mymodel">
        <source name="source" translator-name="oracle-interceptor" connection-jndi-name="java:oracle-ds"/>

    <!-- the below it is called translator overriding, where you can set different properties -->
    <translator name="orcle-interceptor" type="interceptor" />
        <property name="delegateName" value="oracle" />

We have defined a "translator" override called "oracle-interceptor", which is based on the custom translator "interceptor" from above, and supplied the translator it needs to delegate to "oracle" as its delegateName. Then, we used this override translator "oracle-interceptor" in your VDB. Now any calls going into this VDB model's translator will be intercepted by YOUR code to do whatever you want to do.

JBoss.org Content Archive (Read Only), exported from JBoss Community Documentation Editor at 2020-03-13 12:26:57 UTC, last content change 2012-11-14 19:35:01 UTC.