Java Code Examples for org.apache.pig.FuncSpec#getClassName()

/**
 * Converts a Pig UDF, given its {@link FuncSpec} and a list of relational
 * operands (function arguments). To call this function, the arguments of
 * Pig functions need to be converted into the relational types before.
 *
 * @param builder The relational builder
 * @param pigFunc Pig function description
 * @param operands Relational operands for the function
 * @param returnType Function return data type
 * @return The SQL calls equivalent to the Pig function
 */
static RexNode convertPigFunction(PigRelBuilder builder, FuncSpec pigFunc,
    ImmutableList<RexNode> operands, RelDataType returnType) throws FrontendException {
  // First, check the map for the direct mapping SQL builtin
  final SqlOperator operator = BUILTIN_FUNC.get(pigFunc.getClassName());
  if (operator != null) {
    return builder.call(operator, operands);
  }

  // If no mapping found, build the argument wrapper to convert the relation operands
  // into a Pig tuple so that the Pig function can consume it.
  try {
    // Find the implementation method for the Pig function from
    // the class defining the UDF.
    final Class clazz = Class.forName(pigFunc.getClassName());
    final Method method =
        PIG_UDF_FINDER.findPigUdfImplementationMethod(clazz);

    // Now create the argument wrapper. Depend on the type of the UDF, the
    // relational operands are converted into a Pig Tuple or Pig DataBag
    // with the appropriate wrapper.
    final SqlUserDefinedFunction convertOp =
        Accumulator.class.isAssignableFrom(clazz)
            ? PigRelSqlUdfs.createPigBagUDF(operands)
            : PigRelSqlUdfs.createPigTupleUDF(operands);
    final RexNode rexTuple = builder.call(convertOp, operands);

    // Then convert the Pig function into a @SqlUserDefinedFunction.
    SqlUserDefinedFunction userFuncOp =
        PigRelSqlUdfs.createGeneralPigUdf(clazz.getSimpleName(),
            method, pigFunc, rexTuple.getType(), returnType);

    // Ready to return SqlCall after having SqlUDF and operand
    return builder.call(userFuncOp, ImmutableList.of(rexTuple));
  } catch (ClassNotFoundException e) {
    throw new FrontendException("Cannot find the implementation for Pig UDF class: "
        + pigFunc.getClassName());
  }
}
 

private Class instantiateCaster(FuncSpec funcSpec) throws VisitorException {
    if ( funcSpec == null ) {
        return null;
    }

    if( func2casterMap.containsKey(funcSpec) ) {
      return func2casterMap.get(funcSpec);
    }

    LoadCaster caster = null;
    Object obj = PigContext.instantiateFuncFromSpec(funcSpec);
    try {
        if (obj instanceof LoadFunc) {
            caster = ((LoadFunc)obj).getLoadCaster();
        } else if (obj instanceof StreamToPig) {
            caster = ((StreamToPig)obj).getLoadCaster();
        } else {
            throw new VisitorException("Invalid class type " + funcSpec.getClassName(),
                                       2270, PigException.BUG );
        }
    } catch (IOException e) {
        throw new VisitorException("Invalid class type " + funcSpec.getClassName(),
                                     2270, e );
    }

    Class retval = (caster == null) ? null : caster.getClass();
    func2casterMap.put(funcSpec, retval);
    return retval;
}
 

@SuppressWarnings("rawtypes")
public Class getClassForAlias(String alias) throws IOException{
    String className = null;
    FuncSpec funcSpec = null;
    if (definedFunctions != null) {
        funcSpec = definedFunctions.get(alias);
    }
    if (funcSpec != null) {
        className = funcSpec.getClassName();
    }else{
        className = FuncSpec.getClassNameFromSpec(alias);
    }
    return resolveClassName(className);
}