How to use

FunctionDesc

in

ca.nrc.cadc.tap.schema

functionDescs.add(new FunctionDesc("AREA", TapDataType.DOUBLE, "deg**2"));
functionDescs.add(new FunctionDesc("CENTROID", TapDataType.POINT));
functionDescs.add(new FunctionDesc("CIRCLE", TapDataType.CIRCLE));
functionDescs.add(new FunctionDesc("CONTAINS", TapDataType.INTEGER));
functionDescs.add(new FunctionDesc("COORD1", TapDataType.DOUBLE, "deg"));
functionDescs.add(new FunctionDesc("COORD2", TapDataType.DOUBLE, "deg"));
functionDescs.add(new FunctionDesc("COORDSYS", new TapDataType("char", "16*", null)));
functionDescs.add(new FunctionDesc("DISTANCE", TapDataType.DOUBLE, "deg"));
functionDescs.add(new FunctionDesc("INTERSECTS", TapDataType.INTEGER));
functionDescs.add(new FunctionDesc("INTERVAL", TapDataType.INTERVAL));
functionDescs.add(new FunctionDesc("POINT", TapDataType.POINT));
functionDescs.add(new FunctionDesc("POLYGON", TapDataType.POLYGON));
functionDescs.add(new FunctionDesc("ABS", TapDataType.FUNCTION_ARG));
functionDescs.add(new FunctionDesc("ACOS", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("ASIN", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("ATAN", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("ATAN2", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("CEILING", TapDataType.FUNCTION_ARG));
functionDescs.add(new FunctionDesc("COS", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("COT", TapDataType.DOUBLE, "radians"));
functionDescs.add(new FunctionDesc("DEGREES", TapDataType.DOUBLE, "deg"));
functionDescs.add(new FunctionDesc("EXP", TapDataType.DOUBLE));
functionDescs.add(new FunctionDesc("FLOOR", TapDataType.FUNCTION_ARG));
functionDescs.add(new FunctionDesc("LN", TapDataType.DOUBLE));
functionDescs.add(new FunctionDesc("LOG", TapDataType.DOUBLE));
functionDescs.add(new FunctionDesc("LOG10", TapDataType.DOUBLE));
functionDescs.add(new FunctionDesc("MOD", TapDataType.FUNCTION_ARG));

/**
 * Find the FunctionDesc for a given Function.
 *
 * @param tapSchema
 * @param function
 * @return FunctionDesc
 */
public static FunctionDesc findFunctionDesc(TapSchema tapSchema, Function function)
{
  if (function == null || function.getName() == null)
    return null;
  for (FunctionDesc functionDesc : tapSchema.getFunctionDescs())
  {
    log.debug("check: " + function.getName() + " vs " + functionDesc.getName());
    if (function.getName().equalsIgnoreCase(functionDesc.getName()))
      return functionDesc;
  }
  return null;
}

  throw new UnsupportedOperationException("invalid function: " + function.getName());
if ( TapDataType.FUNCTION_ARG.equals(functionDesc.getDatatype()) )
      log.debug("vist(nested Function " + nestedFunction);
      FunctionDesc nestedFunctionDesc = TapSchemaUtil.findFunctionDesc(tapSchema, (Function) parameter);
      if ( TapDataType.FUNCTION_ARG.equals(nestedFunctionDesc.getDatatype()) )
          datatype = recursiveFunctionDesc.getDatatype();
        datatype = nestedFunctionDesc.getDatatype();
      return new FunctionDesc(functionDesc.getName(), datatype);

log.debug("visit(function) " + function + " found: " + functionDesc);
if (alias != null)
  paramDesc = new TapSelectItem(alias, functionDesc.getDatatype());
else
  paramDesc = new TapSelectItem(function.getName(), functionDesc.getDatatype());

@Override
public void visit(Function function)
{
  log.debug("visit(function)" + function);
  boolean found = false;
  
  for (FunctionDesc functionDesc : tapSchema.getFunctionDescs())
  {
    if (functionDesc.getName().equalsIgnoreCase(function.getName()))
    {
      found = true;
      break;
    }
  }
  if (!found)
    throw new IllegalArgumentException("Function [" + function.getName() + "] is not found in TapSchema");
  selectNavigator.enterFunctionCall(function);
  if (function.getParameters() != null)
    function.getParameters().accept(this);
  selectNavigator.leaveFunctionCall();
}