3.2. Implementing the Framework

// Get object tree 
LanguageObject objectTree = ...

// Create your visitor initialize as necessary
MyVisitor visitor = new MyVisitor();

// Call the visitor using pre-order visitation
DelegatingHierarchyVisitor.preOrderVisit(visitor, objectTree);

// Retrieve state collected while visiting
int count = visitor.getCount();

package org.teiid.translator.custom;

@Translator(name="custom", description="Connect to My EIS")
public class CustomExecutionFactory extends ExecutionFactory<MyConnectionFactory, MyConnection> {

    public CustomExecutionFactory() {
    }
}

private String foo = "blah";
@TranslatorProperty(display="Foo property", description="description about Foo") 
public String getFoo() 
{
   return foo;
}

public void setFoo(String value) 
{
   this.foo = value;
}

public class MyMetadataProcessor implements MetadataProcessor<Connection> {
 
     public void process(MetadataFactory mf, Connection conn) {
            Object somedata = connection.getSomeMetadata();
 
            Table table = mf.addTable(tableName);
            Column col1 = mf.addColumn("col1", TypeFacility.RUNTIME_NAMES.STRING, table);
            Column col2 = mf.addColumn("col2", TypeFacility.RUNTIME_NAMES.STRING, table);
 
            //add a pushdown function that can also be evaluated in the engine
            Method method = ...           
            FunctionMethod f = mf.addFunction("func", method); 
 
            //add a pushdown aggregate function that can also be evaluated in the engine
            Method aggMethod = ...           
            FunctionMethod af = mf.addFunction("agg", aggMethod);
            af.setAggregateAttributes(new AggregateAttributes());
            ...
     }
}		
	

@TranslatorProperty(display="Column Name Pattern", category=PropertyType.IMPORT, description="Pattern to derive column names")
public String getColumnNamePattern() {
    return columnNamePattern;
}
 
public void setColumnNamePattern(String columnNamePattern) {
    this.columnNamePattern = columnNamePattern;
}

<vdb name="myvdb" version="1">
   <model name="legacydata" type="PHYSICAL">
      <property name="importer.ColumnNamePattern" value="col*"/>
      ....
      <source name = .../>
   </model>
</vdb>

public class MyMetadataProcessor implements MetadataProcessor<Connection> {
     public static final String NAMESPACE = "{http://my.company.corp}";
 
      @ExtensionMetadataProperty(applicable={Table.class}, datatype=String.class, display="File name", description="File Name", required=true)
     public static final String FILE_PROP = NAMESPACE+"FILE";
 
     public void process(MetadataFactory mf, Connection conn) {
            Object somedata = connection.getSomeMetadata();
 
            Table table = mf.addTable(tableName);
            table.setProperty(FILE_PROP, somedata.getFileName());
 
            Column col1 = mf.addColumn("col1", TypeFacility.RUNTIME_NAMES.STRING, table);
            Column col2 = mf.addColumn("col2", TypeFacility.RUNTIME_NAMES.STRING, table);
         
     }
}

for (TableReference tr:query.getFrom()) {
    NamedTable t = (NamedTable) tr;
    Table table = t.getMetadataObject();
    String file = table.getProperty(FILE_PROP);
    ..
}

executionContext.keepExecutionAlive(true);

@TranslatorProperty(display="Copy LOBs",description="If true, returned LOBs will be copied, rather than streamed from the source",advanced=true)
public boolean isCopyLobs() {
    return copyLobs;
}
     
public void setCopyLobs(boolean copyLobs) {
    this.copyLobs = copyLobs;
}

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vdb name="vdb" version="1">
    <model name="PM1">
        <source name="connector" translator-name="my-translator-override" />
    </model>
    <translator name="my-translator-override" type="my-translator">
        <property name="CopyLobs" value="true" />
    </translator>
</vdb>

@Translator(name = "my-translator", description = "My Translator")
public class MyExecutionFactory extends ExecutionFactory<ConnectionFactory, MyConnection> {
...
    public MetadataProcessor<C> getMetadataProcessor() {
        return MyMetadataProcessor();
    }
}
 
public MyMetadataProcessor implements MetadataProcessor<MyConnection> {
 
    public void process(MetadataFactory metadataFactory, MyConnection connection) throws TranslatorException{
        // schema generation code here
    }
 
    @TranslatorProperty(display="Header Row Number", category=PropertyType.IMPORT, description="Row number that contains the header information")
    public int getHeaderRowNumber() {
        return headerRowNumber;
    }
 
    public void setHeaderRowNumber(int headerRowNumber) {
        this.headerRowNumber = headerRowNumber;
    }
}

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vdb name="vdb" version="1">
    <model name="PM1">
        <property name="importer.HeaderRowNumber" value="12"/>
        <source name="connector" translator-name="my-translator" />
    </model>
</vdb>

public class MyMetadataProcessor implements MetadataProcessor<MyConnection> {
    public static final String URI = "{http://www.teiid.org/translator/mytranslator/2014}";
     
    @ExtensionMetadataProperty(applicable=Table.class, datatype=String.class, display="Encoding", description="Encoding", required=true)
    public static final String ENCODING = URI+"encode";
 
    public void process(MetadataFactory mf, FileConnection conn) throws TranslatorException {
        ..
        Table t = mf.addTable(tableName);
        t.setProperty(ENCODING, "UTF-16");
         
        // add columns etc.
        ..
    }
}

Select select = (Select)command;
NamedTable tableReferece = select.getFrom().get(0);
Table t = tableReference.getMetadataObject();
String encoding = t.getProperty(MyMetadataProcessor.ENCODING, false);
 
// use the encoding value as needed to marshal or unmarshal data 

FunctionMethod addPushDownFunction(String qualifier, String name, String returnType, String...paramTypes)

public void start() throws TranslatorException {
  super.start();
  FunctionMethod func = addPushDownFunciton("oracle", "concat", "string", "string", "string");
  func.setVarArgs(true);
  ...
}