How to use

JavaFunction

in

org.h2.expression

private JavaFunction readJavaFunction(Schema schema, String functionName) {
  FunctionAlias functionAlias = null;
  if (schema != null) {
    functionAlias = schema.findFunction(functionName);
  } else {
    functionAlias = findFunctionAlias(session.getCurrentSchemaName(),
        functionName);
  }
  if (functionAlias == null) {
    throw DbException.get(ErrorCode.FUNCTION_NOT_FOUND_1, functionName);
  }
  Expression[] args;
  ArrayList<Expression> argList = New.arrayList();
  int numArgs = 0;
  while (!readIf(")")) {
    if (numArgs++ > 0) {
      read(",");
    }
    argList.add(readExpression());
  }
  args = argList.toArray(new Expression[0]);
  return new JavaFunction(functionAlias, args);
}

@Override
public Expression[] getExpressionColumns(Session session) {
  switch (getType()) {
  case Value.RESULT_SET:
    ValueResultSet rs = getValueForColumnList(session, getArgs());
    return getExpressionColumns(session, rs.getResultSet());
  case Value.ARRAY:
    return getExpressionColumns(session, (ValueArray) getValue(session));
  }
  return super.getExpressionColumns(session);
}

@Override
public Expression optimize(Session session) {
  boolean allConst = isDeterministic();
  for (int i = 0, len = args.length; i < len; i++) {
    Expression e = args[i].optimize(session);
    args[i] = e;
    allConst &= e.isConstant();
  }
  if (allConst) {
    return ValueExpression.get(getValue(session));
  }
  return this;
}

GridSqlFunction res = new GridSqlFunction(alias.getSchema().getName(), f.getName());
if (f.getArgs() != null) {
  for (Expression arg : f.getArgs())
    res.addChild(parseExpression(arg, calcTypes));

@Override
public int getScale() {
  return DataType.getDataType(getType()).defaultScale;
}

@Override
public boolean isEverything(ExpressionVisitor visitor) {
  switch (visitor.getType()) {
  case ExpressionVisitor.DETERMINISTIC:
    if (!isDeterministic()) {
      return false;
    }
    // only if all parameters are deterministic as well
    break;
  case ExpressionVisitor.GET_DEPENDENCIES:
    visitor.addDependency(functionAlias);
    break;
  default:
  }
  for (Expression e : args) {
    if (e != null && !e.isEverything(visitor)) {
      return false;
    }
  }
  return true;
}

GridSqlFunction res = new GridSqlFunction(alias.getSchema().getName(), f.getName());
if (f.getArgs() != null) {
  for (Expression arg : f.getArgs())
    res.addChild(parseExpression(arg, calcTypes));

@Override
public int getScale() {
  return DataType.getDataType(getType()).defaultScale;
}

@Override
public boolean isEverything(ExpressionVisitor visitor) {
  switch (visitor.getType()) {
  case ExpressionVisitor.DETERMINISTIC:
    if (!isDeterministic()) {
      return false;
    }
    // only if all parameters are deterministic as well
    break;
  case ExpressionVisitor.GET_DEPENDENCIES:
    visitor.addDependency(functionAlias);
    break;
  default:
  }
  for (Expression e : args) {
    if (e != null && !e.isEverything(visitor)) {
      return false;
    }
  }
  return true;
}

@Override
public Expression[] getExpressionColumns(Session session) {
  switch (getType()) {
  case Value.RESULT_SET:
    ValueResultSet rs = getValueForColumnList(session, getArgs());
    return getExpressionColumns(session, rs.getResultSet());
  case Value.ARRAY:
    return getExpressionColumns(session, (ValueArray) getValue(session));
  }
  return super.getExpressionColumns(session);
}

private Expression readFunctionWithoutParameters(String name) {
  if (readIf("(")) {
    read(")");
  }
  if (database.isAllowBuiltinAliasOverride()) {
    FunctionAlias functionAlias = database.getSchema(session.getCurrentSchemaName()).findFunction(name);
    if (functionAlias != null) {
      return new JavaFunction(functionAlias, new Expression[0]);
    }
  }
  Function function = Function.getFunction(database, name);
  function.doneWithParameters();
  return function;
}

@Override
public Expression optimize(Session session) {
  boolean allConst = isDeterministic();
  for (int i = 0, len = args.length; i < len; i++) {
    Expression e = args[i].optimize(session);
    args[i] = e;
    allConst &= e.isConstant();
  }
  if (allConst) {
    return ValueExpression.get(getValue(session));
  }
  return this;
}

@Override
public int getScale() {
  return DataType.getDataType(getType()).defaultScale;
}

@Override
public boolean isEverything(ExpressionVisitor visitor) {
  switch (visitor.getType()) {
  case ExpressionVisitor.DETERMINISTIC:
    if (!isDeterministic()) {
      return false;
    }
    // only if all parameters are deterministic as well
    break;
  case ExpressionVisitor.GET_DEPENDENCIES:
    visitor.addDependency(functionAlias);
    break;
  default:
  }
  for (Expression e : args) {
    if (e != null && !e.isEverything(visitor)) {
      return false;
    }
  }
  return true;
}

@Override
public Expression[] getExpressionColumns(Session session) {
  switch (getType()) {
  case Value.RESULT_SET:
    ValueResultSet rs = getValueForColumnList(session, getArgs());
    return getExpressionColumns(session, rs.getResultSet());
  case Value.ARRAY:
    return getExpressionColumns(session, (ValueArray) getValue(session));
  }
  return super.getExpressionColumns(session);
}

  r = new JavaFunction(f, args);
} else {
  Column col = parseColumnWithType(null);

@Override
public Expression optimize(Session session) {
  boolean allConst = isDeterministic();
  for (int i = 0, len = args.length; i < len; i++) {
    Expression e = args[i].optimize(session);
    args[i] = e;
    allConst &= e.isConstant();
  }
  if (allConst) {
    return ValueExpression.get(getValue(session));
  }
  return this;
}

private JavaFunction readJavaFunction(Schema schema, String functionName) {
  FunctionAlias functionAlias = null;
  if (schema != null) {
    functionAlias = schema.findFunction(functionName);
  } else {
    functionAlias = findFunctionAlias(session.getCurrentSchemaName(),
        functionName);
  }
  if (functionAlias == null) {
    throw DbException.get(ErrorCode.FUNCTION_NOT_FOUND_1, functionName);
  }
  Expression[] args;
  ArrayList<Expression> argList = New.arrayList();
  int numArgs = 0;
  while (!readIf(")")) {
    if (numArgs++ > 0) {
      read(",");
    }
    argList.add(readExpression());
  }
  args = new Expression[numArgs];
  argList.toArray(args);
  JavaFunction func = new JavaFunction(functionAlias, args);
  return func;
}

private JavaFunction readJavaFunction(Schema schema, String functionName) {
  FunctionAlias functionAlias = null;
  if (schema != null) {
    functionAlias = schema.findFunction(functionName);
  } else {
    functionAlias = findFunctionAlias(session.getCurrentSchemaName(),
        functionName);
  }
  if (functionAlias == null) {
    throw DbException.get(ErrorCode.FUNCTION_NOT_FOUND_1, functionName);
  }
  Expression[] args;
  ArrayList<Expression> argList = New.arrayList();
  int numArgs = 0;
  while (!readIf(")")) {
    if (numArgs++ > 0) {
      read(",");
    }
    argList.add(readExpression());
  }
  args = new Expression[numArgs];
  argList.toArray(args);
  JavaFunction func = new JavaFunction(functionAlias, args);
  return func;
}

private JavaFunction readJavaFunction(String name) throws SQLException {
  FunctionAlias functionAlias = database.findFunctionAlias(name);
  if (functionAlias == null) {
    // TODO compatibility: support 'on the fly java functions' as HSQLDB
    // ( CALL "java.lang.Math.sqrt"(2.0) )
    throw Message.getSQLException(ErrorCode.FUNCTION_NOT_FOUND_1, name);
  }
  int paramCount = functionAlias.getParameterCount();
  Expression[] args = new Expression[paramCount];
  for (int i = 0; i < args.length; i++) {
    if (i > 0) {
      read(",");
    }
    args[i] = readExpression();
  }
  read(")");
  JavaFunction func = new JavaFunction(functionAlias, args);
  return func;
}