Source: src/main/javascript/oracle/oj/ojdatagrid-model/CollectionCellSet.js

/**
 * Copyright (c) 2014, Oracle and/or its affiliates.
 * All rights reserved.
 */
 
/**
 * @export
 * A CellSet represents a collection of cells.  The CellSet is an object returned by the success callback
 * of the fetchCells method on DataGridDataSource.  The CollectionCellSet is an oj collection specific 
 * implementation of methods on CellSet. 
 * @param {number} startRow the start row index of the cell set
 * @param {number} endRow the end row index of the cell set
 * @param {number} startColumn the start column index of the cell set
 * @param {number} endColumn the end column index of the cell set
 * @param {Array|null} columns the set of column keys
 * @constructor
 */
oj.CollectionCellSet = function(startRow, endRow, startColumn, endColumn, columns)
{
    // assert startRow/startColumn are number
    oj.Assert.assertNumber(startRow, null);
    oj.Assert.assertNumber(endRow, null);
    oj.Assert.assertNumber(startColumn, null);
    oj.Assert.assertNumber(endColumn, null);
    oj.Assert.assertArrayOrNull(columns);

    this.m_startRow = startRow;
    this.m_endRow = endRow;
    this.m_startColumn = startColumn;
    this.m_endColumn = endColumn;
    this.m_columns = columns;
};

/**
 * Sets the models used in this cell set.
 * @param {Array} models an array of oj model for the cell set
 * @private
 */
oj.CollectionCellSet.prototype.setModels = function(models)
{
    oj.Assert.assertArray(models);
    // make sure the array size is valid
    if (models != null && models.length === this.getCount("row"))
    {
        this.m_models = models;
    }
};

/**
 * Gets the data of the specified index.  An error is throw when 1) the range is not yet available 
 * 2) the index specified is out of bounds. 
 * @param {Object} indexes the index of each axis in which we want to retrieve the data from.  
 * @param {number} indexes.row the index of the row axis.
 * @param {number} indexes.column the index of the column axis.
 * @return {Object} the data object for the specified index.
 * @export
 */
oj.CollectionCellSet.prototype.getData = function(indexes)
{
    var column, model;

    // indexes are validated in _getModel
    model = this._getModel(indexes);
    if (model == null)
    {
        return null;
    }

    // extract column index
    column = indexes['column'];

    return model.get(this.m_columns[column]);
};

/**
 * Gets the metadata of the specified index.  An error is throw when 1) the range is not yet available 
 * 2) the index specified is out of bounds. 
 * @param {Object} indexes the index of each axis in which we want to retrieve the metadata from.  
 * @param {number} indexes.row the index of the row axis.
 * @param {number} indexes.column the index of the column axis.
 * @return the metadata object for the specific index.  The metadata that the DataGrid supports are: 
 *         1) keys - the key (of each axis) of the cell.
 * @export
 */
oj.CollectionCellSet.prototype.getMetadata = function(indexes)
{
    var column, model, keys;

    // indexes are validated in _getModel
    model = this._getModel(indexes);
    if (model == null)
    {
        return null;
    }

    // extract column index
    column = indexes['column'];

    keys = {"row": oj.CollectionDataGridUtils._getModelKey(model), "column": this.m_columns[column]};
    return {"keys": keys};
};

/**
 * Gets the Model based on indexes.
 * @private
 */
oj.CollectionCellSet.prototype._getModel = function(indexes)
{
    var row, column;

    // make sure models is populated
    if (this.m_models == null)
    {
        return null;
    }

    oj.Assert.assertObject(indexes);

    // extract row and column index
    row = indexes['row'];
    column = indexes['column'];

    // make sure index are valid
    oj.Assert.assert(row >= this.m_startRow && row <= this.m_endRow && column >= this.m_startColumn && column <= this.m_endColumn); 

    return this.m_models[row - this.m_startRow];
};

/**
 * Gets the actual count of the result set for the specified axis.  Valid values are "row" and "column".
 * @param {string} axis the axis in which to inquire the actual count of the result set.
 * @return {number} the actual count of the result set for the specified axis.  
 * @export
 */
oj.CollectionCellSet.prototype.getCount = function(axis)
{
    if (axis === "row")
    {
        return Math.max(0, this.m_endRow - this.m_startRow);
    }
    
    if (axis === "column")
    {
        return Math.max(0, this.m_endColumn - this.m_startColumn);
    }

    return 0;
};

/**
 * Gets the m_startRow property for testing
 * @export
 * @ignore
 */
oj.CollectionCellSet.prototype.getStartRow = function()
{
    return this.m_startRow;
};

/**
 * Gets the m_endRow property for testing
 * @export
 * @ignore
 */
oj.CollectionCellSet.prototype.getEndRow = function()
{
    return this.m_endRow;
};

/**
 * Gets the m_startColumn property for testing
 * @export
 * @ignore
 */
oj.CollectionCellSet.prototype.getStartColumn = function()
{
    return this.m_startColumn;
};

/**
 * Gets the m_endColumn property for testing
 * @export
 * @ignore
 */
oj.CollectionCellSet.prototype.getEndColumn = function()
{
    return this.m_endColumn;
};

/**
 * Gets the m_columns property for testing
 * @export
 * @ignore
 */
oj.CollectionCellSet.prototype.getColumns = function()
{
    return this.m_columns;
};