org.apache.calcite.sql.SqlFunction Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.calcite.sql;
import org.apache.calcite.linq4j.function.Functions;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.sql.type.SqlOperandTypeChecker;
import org.apache.calcite.sql.type.SqlOperandTypeInference;
import org.apache.calcite.sql.type.SqlReturnTypeInference;
import org.apache.calcite.sql.validate.SqlValidator;
import org.apache.calcite.sql.validate.SqlValidatorScope;
import org.apache.calcite.sql.validate.implicit.TypeCoercion;
import org.apache.calcite.util.Util;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.Objects;
import javax.annotation.Nonnull;
import static org.apache.calcite.util.Static.RESOURCE;
/**
* A SqlFunction is a type of operator which has conventional
* function-call syntax.
*/
public class SqlFunction extends SqlOperator {
//~ Instance fields --------------------------------------------------------
private final SqlFunctionCategory category;
private final SqlIdentifier sqlIdentifier;
private final List paramTypes;
//~ Constructors -----------------------------------------------------------
/**
* Creates a new SqlFunction for a call to a builtin function.
*
* @param name Name of builtin function
* @param kind kind of operator implemented by function
* @param returnTypeInference strategy to use for return type inference
* @param operandTypeInference strategy to use for parameter type inference
* @param operandTypeChecker strategy to use for parameter type checking
* @param category categorization for function
*/
public SqlFunction(
String name,
SqlKind kind,
SqlReturnTypeInference returnTypeInference,
SqlOperandTypeInference operandTypeInference,
SqlOperandTypeChecker operandTypeChecker,
SqlFunctionCategory category) {
// We leave sqlIdentifier as null to indicate
// that this is a builtin. Same for paramTypes.
this(name, null, kind, returnTypeInference, operandTypeInference,
operandTypeChecker, null, category);
assert !((category == SqlFunctionCategory.USER_DEFINED_CONSTRUCTOR)
&& (returnTypeInference == null));
}
/**
* Creates a placeholder SqlFunction for an invocation of a function with a
* possibly qualified name. This name must be resolved into either a builtin
* function or a user-defined function.
*
* @param sqlIdentifier possibly qualified identifier for function
* @param returnTypeInference strategy to use for return type inference
* @param operandTypeInference strategy to use for parameter type inference
* @param operandTypeChecker strategy to use for parameter type checking
* @param paramTypes array of parameter types
* @param funcType function category
*/
public SqlFunction(
SqlIdentifier sqlIdentifier,
SqlReturnTypeInference returnTypeInference,
SqlOperandTypeInference operandTypeInference,
SqlOperandTypeChecker operandTypeChecker,
List paramTypes,
SqlFunctionCategory funcType) {
this(Util.last(sqlIdentifier.names), sqlIdentifier, SqlKind.OTHER_FUNCTION,
returnTypeInference, operandTypeInference, operandTypeChecker,
paramTypes, funcType);
}
/**
* Internal constructor.
*/
protected SqlFunction(
String name,
SqlIdentifier sqlIdentifier,
SqlKind kind,
SqlReturnTypeInference returnTypeInference,
SqlOperandTypeInference operandTypeInference,
SqlOperandTypeChecker operandTypeChecker,
List paramTypes,
SqlFunctionCategory category) {
super(name, kind, 100, 100, returnTypeInference, operandTypeInference,
operandTypeChecker);
this.sqlIdentifier = sqlIdentifier;
this.category = Objects.requireNonNull(category);
this.paramTypes =
paramTypes == null ? null : ImmutableList.copyOf(paramTypes);
}
//~ Methods ----------------------------------------------------------------
public SqlSyntax getSyntax() {
return SqlSyntax.FUNCTION;
}
/**
* @return fully qualified name of function, or null for a builtin function
*/
public SqlIdentifier getSqlIdentifier() {
return sqlIdentifier;
}
@Override public SqlIdentifier getNameAsId() {
if (sqlIdentifier != null) {
return sqlIdentifier;
}
return super.getNameAsId();
}
/**
* @return array of parameter types, or null for builtin function
*/
public List getParamTypes() {
return paramTypes;
}
/**
* Returns a list of parameter names.
*
* The default implementation returns {@code [arg0, arg1, ..., argN]}.
*/
public List getParamNames() {
return Functions.generate(paramTypes.size(), i -> "arg" + i);
}
public void unparse(
SqlWriter writer,
SqlCall call,
int leftPrec,
int rightPrec) {
getSyntax().unparse(writer, this, call, leftPrec, rightPrec);
}
/**
* @return function category
*/
@Nonnull public SqlFunctionCategory getFunctionType() {
return this.category;
}
/**
* Returns whether this function allows a DISTINCT or
* ALL quantifier. The default is false; some aggregate
* functions return true.
*/
public boolean isQuantifierAllowed() {
return false;
}
public void validateCall(
SqlCall call,
SqlValidator validator,
SqlValidatorScope scope,
SqlValidatorScope operandScope) {
// This implementation looks for the quantifier keywords DISTINCT or
// ALL as the first operand in the list. If found then the literal is
// not called to validate itself. Further the function is checked to
// make sure that a quantifier is valid for that particular function.
//
// If the first operand does not appear to be a quantifier then the
// parent ValidateCall is invoked to do normal function validation.
super.validateCall(call, validator, scope, operandScope);
validateQuantifier(validator, call);
}
/**
* Throws a validation error if a DISTINCT or ALL quantifier is present but
* not allowed.
*/
protected void validateQuantifier(SqlValidator validator, SqlCall call) {
if ((null != call.getFunctionQuantifier()) && !isQuantifierAllowed()) {
throw validator.newValidationError(call.getFunctionQuantifier(),
RESOURCE.functionQuantifierNotAllowed(call.getOperator().getName()));
}
}
public RelDataType deriveType(
SqlValidator validator,
SqlValidatorScope scope,
SqlCall call) {
return deriveType(validator, scope, call, true);
}
private RelDataType deriveType(
SqlValidator validator,
SqlValidatorScope scope,
SqlCall call,
boolean convertRowArgToColumnList) {
// Scope for operands. Usually the same as 'scope'.
final SqlValidatorScope operandScope = scope.getOperandScope(call);
// Indicate to the validator that we're validating a new function call
validator.pushFunctionCall();
final List argNames = constructArgNameList(call);
final List args = constructOperandList(validator, call, argNames);
final List argTypes = constructArgTypeList(validator, scope,
call, args, convertRowArgToColumnList);
SqlFunction function =
(SqlFunction) SqlUtil.lookupRoutine(validator.getOperatorTable(),
getNameAsId(), argTypes, argNames, getFunctionType(),
SqlSyntax.FUNCTION, getKind(),
validator.getCatalogReader().nameMatcher(),
false);
try {
// if we have a match on function name and parameter count, but
// couldn't find a function with a COLUMN_LIST type, retry, but
// this time, don't convert the row argument to a COLUMN_LIST type;
// if we did find a match, go back and re-validate the row operands
// (corresponding to column references), now that we can set the
// scope to that of the source cursor referenced by that ColumnList
// type
if (convertRowArgToColumnList && containsRowArg(args)) {
if (function == null
&& SqlUtil.matchRoutinesByParameterCount(
validator.getOperatorTable(), getNameAsId(), argTypes,
getFunctionType(),
validator.getCatalogReader().nameMatcher())) {
// remove the already validated node types corresponding to
// row arguments before re-validating
for (SqlNode operand : args) {
if (operand.getKind() == SqlKind.ROW) {
validator.removeValidatedNodeType(operand);
}
}
return deriveType(validator, scope, call, false);
} else if (function != null) {
validator.validateColumnListParams(function, argTypes, args);
}
}
if (getFunctionType() == SqlFunctionCategory.USER_DEFINED_CONSTRUCTOR) {
return validator.deriveConstructorType(scope, call, this, function,
argTypes);
}
if (function == null && validator.isTypeCoercionEnabled()) {
// try again if implicit type coercion is allowed.
boolean changed = false;
function = (SqlFunction) SqlUtil.lookupRoutine(validator.getOperatorTable(),
getNameAsId(), argTypes, argNames, getFunctionType(), SqlSyntax.FUNCTION, getKind(),
validator.getCatalogReader().nameMatcher(),
true);
// try to coerce the function arguments to the declared sql type name.
// if we succeed, the arguments would be wrapped with CAST operator.
if (function != null) {
TypeCoercion typeCoercion = validator.getTypeCoercion();
changed = typeCoercion.userDefinedFunctionCoercion(scope, call, function);
}
if (!changed) {
throw validator.handleUnresolvedFunction(call, this, argTypes,
argNames);
}
}
// REVIEW jvs 25-Mar-2005: This is, in a sense, expanding
// identifiers, but we ignore shouldExpandIdentifiers()
// because otherwise later validation code will
// choke on the unresolved function.
((SqlBasicCall) call).setOperator(function);
return function.validateOperands(
validator,
operandScope,
call);
} finally {
validator.popFunctionCall();
}
}
private boolean containsRowArg(List args) {
for (SqlNode operand : args) {
if (operand.getKind() == SqlKind.ROW) {
return true;
}
}
return false;
}
}
// End SqlFunction.java