TableCommitCallback.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 System.Collections.Generic;

using Deveel.Data;
using Deveel.Data.Sql;

namespace Deveel.Data.Transactions {
    public abstract class TableCommitCallback {
        private readonly List<int> addedList;
        private readonly List<int> removedList;

        protected TableCommitCallback(ObjectName tableName) {
            if (tableName == null)
                throw new ArgumentNullException("tableName");

            TableName = tableName;

            addedList = new List<int>();
            removedList = new List<int>();
        }

        public ObjectName TableName { get; private set; }

        protected bool IsInTransaction { get; private set; }

        internal void OnTransactionStarted() {
            IsInTransaction = true;
            Act();
        }

        internal void OnTransactionEnd() {
            IsInTransaction = false;
            Act();
        }

        public void AttachTo(ITransaction transaction) {
            transaction.RegisterOnCommit(OnCommit);

            if (transaction is ICallbackHandler)
                ((ICallbackHandler)transaction).OnCallbackAttached(this);
        }

        public void DetachFrom(ITransaction transaction) {
            transaction.UnregisterOnCommit(OnCommit);

            if (transaction is ICallbackHandler)
                ((ICallbackHandler)transaction).OnCallbackDetached(this);
        }

        private void Act() {
            IList<int> add, remove;
            lock (removedList) {
                add = new List<int>(addedList);
                remove = new List<int>(removedList);

                addedList.Clear();
                removedList.Clear();
            }

            OnAction(add, remove);
        }

        private void OnCommit(TableCommitInfo commitInfo) {
            if (TableName.Equals(commitInfo.TableName)) {
                addedList.AddRange(commitInfo.AddedRows);
                removedList.AddRange(commitInfo.RemovedRows);
            }
        }

        protected abstract void OnAction(IEnumerable<int> addedRows, IEnumerable<int> removedRows);
    }
}