Function.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed 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.
//

using System;

using Deveel.Data.Sql;
using Deveel.Data.Sql.Expressions;
using Deveel.Data.Sql.Objects;
using Deveel.Data.Types;

namespace Deveel.Data.Routines {
    public abstract class Function : IFunction {
        public static readonly SqlType DynamicType = new DynamicSqlType();

        protected Function(FunctionInfo functionInfo) {
            if (functionInfo == null)
                throw new ArgumentNullException("functionInfo");

            FunctionInfo = functionInfo;
        }

        protected Function(ObjectName name, RoutineParameter[] parameters, FunctionType functionType) 
            : this(name, parameters, null, functionType) {
        }

        protected Function(ObjectName name, RoutineParameter[] parameters, SqlType returnType) 
            : this(name, parameters, returnType, FunctionType.Static) {
        }

        protected Function(ObjectName name, RoutineParameter[] parameters, SqlType returnType, FunctionType functionType)
            : this(new FunctionInfo(name, parameters, returnType, functionType)) {
        }

        public FunctionType FunctionType {
            get { return FunctionInfo.FunctionType; }
        }

        public FunctionInfo FunctionInfo { get; private set; }

        public ObjectName FunctionName {
            get { return FunctionInfo.RoutineName; }
        }

        RoutineInfo IRoutine.RoutineInfo {
            get { return FunctionInfo; }
        }

        RoutineType IRoutine.Type {
            get { return RoutineType.Function; }
        }

        DbObjectType IDbObject.ObjectType {
            get { return DbObjectType.Routine; }
        }

        ObjectName IDbObject.FullName {
            get { return FunctionName; }
        }

        public abstract InvokeResult Execute(InvokeContext context);

        public SqlType ReturnType() {
            if (FunctionInfo.ReturnType != null)
                return FunctionInfo.ReturnType;

            return ReturnType(null);
        }

        public virtual SqlType ReturnType(InvokeContext context) {
            return FunctionInfo.ReturnType;
        }

        #region DynamicType

        class DynamicSqlType : SqlType {
            public DynamicSqlType()
                : base("DYNAMIC", SqlTypeCode.Object) {
            }

            public override bool IsComparable(SqlType type) {
                return true;
            }

            public override int Compare(ISqlObject x, ISqlObject y) {
                throw new NotSupportedException();
            }
        }

        #endregion
    }
}