Using Genero records

When passing a RECORD to a Java™ method, the runtime system converts the RECORD to an instance of the com.fourjs.fgl.lang.FglRecord class implemented in FGLDIR/lib/fgl.jar.

The FglRecord object is a copy of the RECORD variable: Structure and members of the FglRecord object can be read within the Java code, but cannot be modified.

You must add FGLDIR/lib/fgl.jar to the class path in order to compile Java code with com.fourjs.fgl.lang.FglRecord class.

The com.fourjs.fgl.lang.FglRecord class implements the following methods:

Table 1. Methods of the com.fourjs.fgl.lang.FglRecord class
Method	Description
int getFieldCount()	Returns the number of record members.
String getFieldName(int p)	Returns the name of the record member at position p.
FglTypes getType(int p)	Returns the `FglTypes` constant of the record member at position p.
String getTypeName(int p)	Returns the string representation of the data type of the record member at position p.
int getTypeQualifier(int p)	Returns the encoded type qualifier of the record member at position p.
int getInt(int p)	Returns the int value of the record member at position p.
int getFloat(int p)	Returns the float value of the record member at position p.
double getDouble(int p)	Returns the double value of the record member at position p.
String getString(int p)	Returns the String representation of the value of the record member at position p.
FglDecimal getDecimal(int p)	Returns the `FglDecimal` value of the record member at position p.
FglDate getDate(int p)	Returns the `FglDate` value of the record member at position p.
FglDateTime getDateTime(int p)	Returns the `FglDateTime` value of the record member at position p.
FglInterval getInterval(int p)	Returns the `FglInterval` value of the record member at position p.
FglByteBlob getByteBlob(int p)	Returns the `FglByteBlob` value of the record member at position p.
FglTextBlob getTextBlob(int p)	Returns the `FglTextBlob` value of the record member at position p.

In the Java code, use the query methods of the com.fourjs.fgl.lang.FglRecord to identify the members of the RECORD:

public static void showMemberTypes(FglRecord rec){
    int i;
    int n = rec.getFieldCount();
    for (i = 1; i <= n; i++)
        System.out.println( String.valueOf(i) + ":" +
        rec.getFieldName(i) + " / " + rec.getTypeName(i) );
}

When assigning a RECORD to a com.fourjs.fgl.lang.FglRecord, widening conversion applies implicitly. But when assigning a com.fourjs.fgl.lang.FglRecord to a RECORD, narrowing conversion applies and you must explicitly CAST the original object reference to the type of the RECORD. The next example shows how to return an FglRecord object from a Java method:

-- PassRecord.4gl
IMPORT JAVA com.fourjs.fgl.lang.FglRecord
IMPORT JAVA UseRecord
MAIN
    TYPE type1 RECORD
               id INTEGER,
               name VARCHAR(50)
           END RECORD
    DEFINE rec1, rec2 type1
    LET rec1.id = 123
    LET rec1.name = "McFly"
    LET rec2 = CAST(UseRecord.getRecord(rec1) AS type1)
END MAIN

-- UseRecord.java
import com.fourjs.fgl.lang.FglRecord;
public class UseRecord{
    public static FglRecord getRecord(FglRecord rec){
        ...
        return rec;
    }
}