@qooxdoo/framework/source/class/qx/ui/virtual/cell/AbstractWidget.js

The JS Framework for Coders

/**
 * Abstract base class for widget based cell renderer.
 */
qx.Class.define("qx.ui.virtual.cell.AbstractWidget", {
  extend: qx.core.Object,
  implement: [qx.ui.virtual.cell.IWidgetCell],

  construct() {
    super();

    this.__pool = [];
  },

  events: {
    /** Fired when a new <code>LayoutItem</code> is created. */
    created: "qx.event.type.Data"
  },

  members: {
    __pool: null,

    /**
     * Creates the widget instance.
     *
     * @abstract
     * @return {qx.ui.core.LayoutItem} The widget used to render a cell
     */
    _createWidget() {
      throw new Error("abstract method call");
    },

    // interface implementation
    updateData(widget, data) {
      throw new Error("abstract method call");
    },

    // interface implementation
    updateStates(widget, states) {
      var oldStates = widget.getUserData("cell.states");

      // remove old states
      if (oldStates) {
        var newStates = states || {};
        for (var state in oldStates) {
          if (!newStates[state]) {
            widget.removeState(state);
          }
        }
      } else {
        oldStates = {};
      }

      // apply new states
      if (states) {
        for (var state in states) {
          if (!oldStates.state) {
            widget.addState(state);
          }
        }
      }

      widget.setUserData("cell.states", states);
    },

    // interface implementation
    getCellWidget(data, states) {
      var widget = this.__getWidgetFromPool();
      this.updateStates(widget, states);
      this.updateData(widget, data);
      return widget;
    },

    // interface implementation
    pool(widget) {
      this.__pool.push(widget);
    },

    /**
     * Cleanup all <code>LayoutItem</code> and destroy them.
     */
    _cleanupPool() {
      var widget = this.__pool.pop();

      while (widget) {
        widget.destroy();
        widget = this.__pool.pop();
      }
    },

    /**
     * Returns a <code>LayoutItem</code> from the pool, when the pool is empty
     * a new <code>LayoutItem</code> is created.
     *
     * @return {qx.ui.core.LayoutItem} The cell widget
     */
    __getWidgetFromPool() {
      var widget = this.__pool.shift();

      if (widget == null) {
        widget = this._createWidget();
        this.fireDataEvent("created", widget);
      }

      return widget;
    }
  },

  /*
   *****************************************************************************
      DESTRUCT
   *****************************************************************************
   */

  destruct() {
    this._cleanupPool();
    this.__pool = null;
  }
});