function TableDataItemSource(tableData, columnName)
{
    this.columnName = columnName;
    this.dataView = new DataSetView(tableData);
    this.eventChanged = new EventHandlers(this);
  
}

TableDataItemSource.prototype = {

    GetData : function()
    {
        if (this.columnName == "") return this.dataView.GetData();
        return this.dataView.GetUniqueValues(this.columnName);
    },

    Init: function ()
    {

    },

    CreateSubView : function(value)
    {
        if (this.columnName == "") return this.dataView;
        return this.dataView.CreateView(this.columnName, value);
    }
};

function FilteredTableDataItemSource(filterFieldName, columnName)
{
    this.filterFiledName = filterFieldName;
    this.columnName = columnName;
    this.eventChanged = new EventHandlers(this);
    this.dataView = null;
    this.initialized = false;
}

FilteredTableDataItemSource.prototype = {

    GetData : function()
    {
        if (this.dataView == null) return [];
        else if (this.columnName == "")
        {
            return this.dataView.GetData();
        }
        
        return this.dataView.GetUniqueValues(this.columnName);
    },

    Init : function()
    {
        if (this.initialized) return;

        this.initialized = true;
        this.filteredField = DocumentForm.GetField(this.filterFiledName);

        if (this.filteredField == null) return;

        this.filteredField.itemSource.Init();

        this.dataView = this.filteredField.itemSource.CreateSubView(this.filteredField.GetValue());
        this.lastFilterValue = this.filteredField.GetValue();
        var self = this;

        var changeHandler = function()
        {
            var filterValue = self.filteredField.GetValue();

            if (self.lastFilterValue != filterValue)
            {
                self.dataView = self.filteredField.itemSource.CreateSubView(filterValue);
                self.eventChanged.Fire();
                self.lastFilterValue = filterValue;
            }
        }
        
        if (!this.filteredField.AddBlurHandler(changeHandler))
        {
            this.filteredField.AddChangedHandler(changeHandler);
        }

        
        this.eventChanged.Fire();
    },

    CreateSubView : function(value)
    {
        if (this.dataView == null) return this.dataView;
        return this.dataView.CreateView(this.columnName, value);
    }
};

function ListDataItemSource(data)
{
    this.data = data;
    this.eventChanged = new EventHandlers(this);
    
}

ListDataItemSource.prototype = {

    Init: function () { },
    GetData: function () { return this.data; }
}

function EmptyItemSource()
{
    this.data = new Array();
    this.eventChanged = new EventHandlers(this);
}

EmptyItemSource.prototype = {
    Init: function () { },
    GetData: function () { return this.data; },
    SetData: function (data) { this.data = data; this.eventChanged.Fire(); },
    Clear: function() { this.SetData(new Array()); }
}

function LinkDropDownControlWithItemSource(dropDownID, hintValue, itemSource)
{
    var dropDownControl = document.getElementById(dropDownID);

    var FillDropDown = function()
    {
        dropDownControl.innerHTML = "";

        if(hintValue != "")
        {
            var option = document.createElement("option");
            option.text = hintValue;
            option.value = "";
            dropDownControl.appendChild(option);
        }


        var dataValues = itemSource.GetData();

        for (var i = 0; i < dataValues.length; i++)
        {
            var option = document.createElement("option");
            var dataValue = dataValues[i];

            if(itemSource.InitOption)
            { 
                itemSource.InitOption(option, dataValue);
            }            
            else 
            {
                option.text = dataValue;
                option.value = dataValue;
            }
            dropDownControl.add(option);
        }

        var documentFormField = DocumentForm.GetField(dropDownID);

        if(documentFormField)
        {
            documentFormField.SetValue( documentFormField.lastSetValue );
        }
      // dropDownControl.dispatchEvent(new Event('change'));
    }
    
    dropDownControl.itemsSource = itemSource;
    itemSource.eventChanged.AddHandler(FillDropDown);
    FillDropDown();
}