/*
// $Id: //open/mondrian-release/3.2/src/main/mondrian/olap/fun/GlobalFunTable.java#1 $
// This software is subject to the terms of the Eclipse Public License v1.0
// Agreement, available at the following URL:
// http://www.eclipse.org/legal/epl-v10.html.
// Copyright (C) 2006-2009 Julian Hyde and others
// All Rights Reserved.
// You must accept the terms of that agreement to use this software.
*/
package mondrian.olap.fun;
import mondrian.olap.FunTable;
import mondrian.olap.Syntax;
import mondrian.olap.Util;
import mondrian.olap.type.Type;
import mondrian.spi.UserDefinedFunction;
import mondrian.util.ServiceDiscovery;
import java.util.List;
/**
* Global function table contains builtin functions and global user-defined
* functions.
*
* @author Gang Chen
* @version $Id: //open/mondrian-release/3.2/src/main/mondrian/olap/fun/GlobalFunTable.java#1 $
*/
public class GlobalFunTable extends FunTableImpl {
private static GlobalFunTable instance = new GlobalFunTable();
static {
instance.init();
}
public static GlobalFunTable instance() {
return instance;
}
private GlobalFunTable() {
}
public void defineFunctions(Builder builder) {
final FunTable builtinFunTable = BuiltinFunTable.instance();
final List<String> reservedWords = builtinFunTable.getReservedWords();
for (String reservedWord : reservedWords) {
builder.defineReserved(reservedWord);
}
final List<Resolver> resolvers = builtinFunTable.getResolvers();
for (Resolver resolver : resolvers) {
builder.define(resolver);
}
for (Class<UserDefinedFunction> udfClass : lookupUdfImplClasses()) {
defineUdf(builder, udfClass);
}
}
private List<Class<UserDefinedFunction>> lookupUdfImplClasses() {
final ServiceDiscovery<UserDefinedFunction> serviceDiscovery =
ServiceDiscovery.forClass(UserDefinedFunction.class);
return serviceDiscovery.getImplementor();
}
/**
* Defines a user-defined function in this table.
*
* <p>If the function is not valid, throws an error.
*
* @param builder Builder
* @param udfClass Class that implements the function
*/
private void defineUdf(
Builder builder,
Class<UserDefinedFunction> udfClass)
{
// Instantiate class with default constructor.
final UserDefinedFunction udf = Util.createUdf(udfClass, null);
// Validate function.
validateFunction(udf);
// Define function.
builder.define(new UdfResolver(udf));
}
/**
* Throws an error if a user-defined function does not adhere to the
* API.
*
* @param udf User defined function
*/
private void validateFunction(final UserDefinedFunction udf) {
// Check that the name is not null or empty.
final String udfName = udf.getName();
if (udfName == null || udfName.equals("")) {
throw Util.newInternal(
"User-defined function defined by class '"
+ udf.getClass() + "' has empty name");
}
// It's OK for the description to be null.
//final String description = udf.getDescription();
final Type[] parameterTypes = udf.getParameterTypes();
for (int i = 0; i < parameterTypes.length; i++) {
Type parameterType = parameterTypes[i];
if (parameterType == null) {
throw Util.newInternal(
"Invalid user-defined function '" + udfName
+ "': parameter type #" + i + " is null");
}
}
// It's OK for the reserved words to be null or empty.
//final String[] reservedWords = udf.getReservedWords();
// Test that the function returns a sensible type when given the FORMAL
// types. It may still fail when we give it the ACTUAL types, but it's
// impossible to check that now.
final Type returnType = udf.getReturnType(parameterTypes);
if (returnType == null) {
throw Util.newInternal(
"Invalid user-defined function '" + udfName
+ "': return type is null");
}
final Syntax syntax = udf.getSyntax();
if (syntax == null) {
throw Util.newInternal(
"Invalid user-defined function '" + udfName
+ "': syntax is null");
}
}
}
// End GlobalFunTable.java