con.setFieldType( DataType.TYPE_DATE );
con.setFieldName( "field1" );
con.setOperator( "==" );
con.setValue( "31-Jan-2010" );
con.setConstraintValueType( SingleFieldConstraint.TYPE_LITERAL );
p.addConstraint( con );
SingleFieldConstraint con2 = new SingleFieldConstraint();
con2.setFieldName( "field2" );
con2.setOperator( "==" );
con2.setValue( "variableHere" );