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easejs/lib/class_final.js

94 lines
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JavaScript

/**
* Wrapper permitting the definition of final classes
*
* Copyright (C) 2010, 2011, 2013, 2014 Free Software Foundation, Inc.
*
* This file is part of GNU ease.js.
*
* ease.js is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
var Class = require( './class' );
/**
* Creates a final class
*
* @return {Function} final class
*/
exports = module.exports = function()
{
markFinal( arguments[ arguments.length - 1 ] );
// forward everything to Class
var result = Class.apply( this, arguments );
if ( !Class.isClass( result ) )
{
finalOverride( result );
}
return result;
};
/**
* Creates a final class from a class extend operation
*
* @return {Function} final class
*/
exports.extend = function()
{
markFinal( arguments[ arguments.length - 1 ] );
return Class.extend.apply( this, arguments );
};
/**
* Causes a definition to be flagged as final
*
* @param {!Arguments} dfn suspected definition object
*
* @return {undefined}
*/
function markFinal( dfn )
{
if ( typeof dfn === 'object' )
{
// mark as abstract
dfn.___$$final$$ = true;
}
}
/**
* Overrides object members to permit final classes
*
* @param {Object} obj object to override
*
* @return {undefined}
*/
function finalOverride( obj )
{
var extend = obj.extend;
// wrap extend, applying the abstract flag
obj.extend = function()
{
markFinal( arguments[ arguments.length - 1 ] );
return extend.apply( this, arguments );
};
}