/** * Limited cache is a size limited cache container that stores limited number of objects. * * When {@link #get} is called, the container will try to find the object in the list. * If failed it will call the {@link #feeder} to create that object. If there are too many * objects in the container, the old ones are removed. * * __Note:__ This is not using a Least Recently Used policy due to simplicity and performance consideration. * @private */Ext.define('Ext.draw.LimitedCache', { config: { /** * @cfg {Number} * The amount limit of the cache. */ limit: 40, /** * @cfg {Function} * Function that generates the object when look-up failed. * @return {Number} */ feeder: function () { return 0; }, /** * @cfg {Object} * The scope for {@link #feeder} */ scope: null }, cache: null, constructor: function (config) { this.cache = {}; this.cache.list = []; this.cache.tail = 0; this.initConfig(config); }, /** * Get a cached object. * @param {String} id * @return {Object} */ get: function (id) { // TODO: Implement cache hit optimization var cache = this.cache, limit = this.getLimit(), feeder = this.getFeeder(), scope = this.getScope() || this; if (cache[id]) { return cache[id].value; } if (cache.list[cache.tail]) { delete cache[cache.list[cache.tail].cacheId]; } cache[id] = cache.list[cache.tail] = { value: feeder.apply(scope, Array.prototype.slice.call(arguments, 1)), cacheId: id }; cache.tail++; if (cache.tail === limit) { cache.tail = 0; } return cache[id].value; }, /** * Clear all the objects. */ clear: function () { this.cache = {}; this.cache.list = []; this.cache.tail = 0; }});