    /**
     * @class Ext.util.Observable
     * Base class that provides a common interface for publishing events. Subclasses are expected to
     * to have a property "events" with all the events defined, and, optionally, a property "listeners"
     * with configured listeners defined.<br>
     * For example:
     * <pre><code>
    Employee = Ext.extend(Ext.util.Observable, {
        constructor: function(config){
            this.name = config.name;
            this.addEvents({
                "fired" : true,
                "quit" : true
            });

            // Copy configured listeners into *this* object so that the base class&#39;s
            // constructor will add them.
            this.listeners = config.listeners;

            // Call our superclass constructor to complete construction process.
            Employee.superclass.constructor.call(this, config)
        }
    });
    </code></pre>
     * This could then be used like this:<pre><code>
    var newEmployee = new Employee({
        name: employeeName,
        listeners: {
            quit: function() {
                // By default, "this" will be the object that fired the event.
                alert(this.name + " has quit!");
            }
        }
    });
    </code></pre>
     */

    Ext.define('Ext.util.Observable', {

        /* Begin Definitions */

        requires: ['Ext.util.Event'],

        statics: {
            /**
             * Removes <b>all</b> added captures from the Observable.
             * @param {Observable} o The Observable to release
             * @static
             */
            releaseCapture: function(o) {
                o.fireEvent = this.prototype.fireEvent;
            },

            /**
             * Starts capture on the specified Observable. All events will be passed
             * to the supplied function with the event name + standard signature of the event
             * <b>before</b> the event is fired. If the supplied function returns false,
             * the event will not fire.
             * @param {Observable} o The Observable to capture events from.
             * @param {Function} fn The function to call when an event is fired.
             * @param {Object} scope (optional) The scope (<code>this</code> reference) in which the function is executed. Defaults to the Observable firing the event.
             * @static
             */
            capture: function(o, fn, scope) {
                o.fireEvent = Ext.Function.createInterceptor(o.fireEvent, fn, scope);
            },

            /**
    Sets observability on the passed class constructor.

    This makes any event fired on any instance of the passed class also fire a single event through
    the __class__ allowing for central handling of events on many instances at once.

    Usage:

        Ext.util.Observable.observe(Ext.data.Connection);
        Ext.data.Connection.on('beforerequest', function(con, options) {
            console.log('Ajax request made to ' + options.url);
        });

             * @param {Function} c The class constructor to make observable.
             * @param {Object} listeners An object containing a series of listeners to add. See {@link #addListener}.
             * @static
             * @markdown
             */
            observe: function(cls, listeners) {
                if (cls) {
                    if (!cls.isObservable) {
                        Ext.applyIf(cls, new this());
                        this.capture(cls.prototype, cls.fireEvent, cls);
                    }
                    if (Ext.isObject(listeners)) {
                        cls.on(listeners);
                    }
                    return cls;
                }
            }
        },

        /* End Definitions */

        /**
        * @cfg {Object} listeners (optional) <p>A config object containing one or more event handlers to be added to this
        * object during initialization.  This should be a valid listeners config object as specified in the
        * {@link #addListener} example for attaching multiple handlers at once.</p>
        * <br><p><b><u>DOM events from ExtJs {@link Ext.Component Components}</u></b></p>
        * <br><p>While <i>some</i> ExtJs Component classes export selected DOM events (e.g. "click", "mouseover" etc), this
        * is usually only done when extra value can be added. For example the {@link Ext.view.View DataView}'s
        * <b><code>{@link Ext.view.View#click click}</code></b> event passing the node clicked on. To access DOM
        * events directly from a child element of a Component, we need to specify the <code>element</code> option to
        * identify the Component property to add a DOM listener to:
        * <pre><code>
    new Ext.panel.Panel({
        width: 400,
        height: 200,
        dockedItems: [{
            xtype: 'toolbar'
        }],
        listeners: {
            click: {
                element: 'el', //bind to the underlying el property on the panel
                fn: function(){ console.log('click el'); }
            },
            dblclick: {
                element: 'body', //bind to the underlying body property on the panel
                fn: function(){ console.log('dblclick body'); }
            }
        }
    });
    </code></pre>
        * </p>
        */
        // @private
        isObservable: true,

        constructor: function(config) {
            var me = this;

            Ext.apply(me, config);
            if (me.listeners) {
                me.on(me.listeners);
                delete me.listeners;
            }
            me.events = me.events || {};

            if (me.bubbleEvents) {
                me.enableBubble(me.bubbleEvents);
            }
        },

        // @private
        eventOptionsRe : /^(?:scope|delay|buffer|single|stopEvent|preventDefault|stopPropagation|normalized|args|delegate|element|vertical|horizontal)$/,

        /**
         * <p>Adds listeners to any Observable object (or Element) which are automatically removed when this Component
         * is destroyed.
         * @param {Observable/Element} item The item to which to add a listener/listeners.
         * @param {Object/String} ename The event name, or an object containing event name properties.
         * @param {Function} fn Optional. If the <code>ename</code> parameter was an event name, this
         * is the handler function.
         * @param {Object} scope Optional. If the <code>ename</code> parameter was an event name, this
         * is the scope (<code>this</code> reference) in which the handler function is executed.
         * @param {Object} opt Optional. If the <code>ename</code> parameter was an event name, this
         * is the {@link Ext.util.Observable#addListener addListener} options.
         */
        addManagedListener : function(item, ename, fn, scope, options) {
            var me = this,
                managedListeners = me.managedListeners = me.managedListeners || [],
                config;

            if (Ext.isObject(ename)) {
                options = ename;
                for (ename in options) {
                    if (options.hasOwnProperty(ename)) {
                        config = options[ename];
                        if (!me.eventOptionsRe.test(ename)) {
                            me.addManagedListener(item, ename, config.fn || config, config.scope || options.scope, config.fn ? config : options);
                        }
                    }
                }
            }
            else {
                managedListeners.push({
                    item: item,
                    ename: ename,
                    fn: fn,
                    scope: scope,
                    options: options
                });

                item.on(ename, fn, scope, options);
            }
        },

        /**
         * Removes listeners that were added by the {@link #mon} method.
         * @param {Observable|Element} item The item from which to remove a listener/listeners.
         * @param {Object|String} ename The event name, or an object containing event name properties.
         * @param {Function} fn Optional. If the <code>ename</code> parameter was an event name, this
         * is the handler function.
         * @param {Object} scope Optional. If the <code>ename</code> parameter was an event name, this
         * is the scope (<code>this</code> reference) in which the handler function is executed.
         */
         removeManagedListener : function(item, ename, fn, scope) {
            var me = this,
                options,
                config,
                managedListeners,
                managedListener,
                length,
                i;

            if (Ext.isObject(ename)) {
                options = ename;
                for (ename in options) {
                    if (options.hasOwnProperty(ename)) {
                        config = options[ename];
                        if (!me.eventOptionsRe.test(ename)) {
                            me.removeManagedListener(item, ename, config.fn || config, config.scope || options.scope);
                        }
                    }
                }
            }

            managedListeners = me.managedListeners ? me.managedListeners.slice() : [];
            length = managedListeners.length;

            for (i = 0; i < length; i++) {
                managedListener = managedListeners[i];
                if (managedListener.item === item && managedListener.ename === ename && (!fn || managedListener.fn === fn) && (!scope || managedListener.scope === scope)) {
                    Ext.Array.remove(me.managedListeners, managedListener);
                    item.un(managedListener.ename, managedListener.fn, managedListener.scope);
                }
            }
        },

        /**
         * <p>Fires the specified event with the passed parameters (minus the event name).</p>
         * <p>An event may be set to bubble up an Observable parent hierarchy (See {@link Ext.Component#getBubbleTarget})
         * by calling {@link #enableBubble}.</p>
         * @param {String} eventName The name of the event to fire.
         * @param {Object...} args Variable number of parameters are passed to handlers.
         * @return {Boolean} returns false if any of the handlers return false otherwise it returns true.
         */
        fireEvent: function() {
            var me = this,
                args = Ext.Array.toArray(arguments),
                ename = args[0].toLowerCase(),
                ret = true,
                event = me.events[ename],
                queue = me.eventQueue,
                parent;

            if (me.eventsSuspended === true) {
                if (queue) {
                    queue.push(args);
                }
            } else if (event && Ext.isObject(event) && event.bubble) {
                if (event.fire.apply(event, args.slice(1)) === false) {
                    return false;
                }
                parent = me.getBubbleTarget && me.getBubbleTarget();
                if (parent && parent.isObservable) {
                    if (!parent.events[ename] || !Ext.isObject(parent.events[ename]) || !parent.events[ename].bubble) {
                        parent.enableBubble(ename);
                    }
                    return parent.fireEvent.apply(parent, args);
                }
            } else if (event && Ext.isObject(event)) {
                args.shift();
                ret = event.fire.apply(event, args);
            }
            return ret;
        },

        /**
         * Appends an event handler to this object.
         * @param {String}   eventName The name of the event to listen for. May also be an object who's property names are event names. See
         * @param {Function} handler The method the event invokes.
         * @param {Object}   scope (optional) The scope (<code><b>this</b></code> reference) in which the handler function is executed.
         * <b>If omitted, defaults to the object which fired the event.</b>
         * @param {Object}   options (optional) An object containing handler configuration.
         * properties. This may contain any of the following properties:<ul>
         * <li><b>scope</b> : Object<div class="sub-desc">The scope (<code><b>this</b></code> reference) in which the handler function is executed.
         * <b>If omitted, defaults to the object which fired the event.</b></div></li>
         * <li><b>delay</b> : Number<div class="sub-desc">The number of milliseconds to delay the invocation of the handler after the event fires.</div></li>
         * <li><b>single</b> : Boolean<div class="sub-desc">True to add a handler to handle just the next firing of the event, and then remove itself.</div></li>
         * <li><b>buffer</b> : Number<div class="sub-desc">Causes the handler to be scheduled to run in an {@link Ext.util.DelayedTask} delayed
         * by the specified number of milliseconds. If the event fires again within that time, the original
         * handler is <em>not</em> invoked, but the new handler is scheduled in its place.</div></li>
         * <li><b>target</b> : Observable<div class="sub-desc">Only call the handler if the event was fired on the target Observable, <i>not</i>
         * if the event was bubbled up from a child Observable.</div></li>
         * <li><b>element</b> : String<div class="sub-desc"><b>This option is only valid for listeners bound to {@link Ext.Component Components}.</b>
         * The name of a Component property which references an element to add a listener to.
         * <p>This option is useful during Component construction to add DOM event listeners to elements of {@link Ext.Component Components} which
         * will exist only after the Component is rendered. For example, to add a click listener to a Panel's body:<pre><code>
    new Ext.panel.Panel({
        title: 'The title',
        listeners: {
            click: this.handlePanelClick,
            element: 'body'
        }
    });
    </code></pre></p>
         * <p>When added in this way, the options available are the options applicable to {@link Ext.core.Element#addListener}</p></div></li>
         * </ul><br>
         * <p>
         * <b>Combining Options</b><br>
         * Using the options argument, it is possible to combine different types of listeners:<br>
         * <br>
         * A delayed, one-time listener.
         * <pre><code>
    myPanel.on('hide', this.handleClick, this, {
    single: true,
    delay: 100
    });</code></pre>
         * <p>
         * <b>Attaching multiple handlers in 1 call</b><br>
         * The method also allows for a single argument to be passed which is a config object containing properties
         * which specify multiple events. For example:<pre><code>
    myGridPanel.on({
        cellClick: this.onCellClick,
        mouseover: this.onMouseOver,
        mouseout: this.onMouseOut,
        scope: this // Important. Ensure "this" is correct during handler execution
    });
    </code></pre>.
         * <p>
         */
        addListener: function(ename, fn, scope, options) {
            var me = this,
                config,
                event;

            if (Ext.isObject(ename)) {
                options = ename;
                for (ename in options) {
                    if (options.hasOwnProperty(ename)) {
                        config = options[ename];
                        if (!me.eventOptionsRe.test(ename)) {
                            me.addListener(ename, config.fn || config, config.scope || options.scope, config.fn ? config : options);
                        }
                    }
                }
            }
            else {
                ename = ename.toLowerCase();
                me.events[ename] = me.events[ename] || true;
                event = me.events[ename] || true;
                if (Ext.isBoolean(event)) {
                    me.events[ename] = event = new Ext.util.Event(me, ename);
                }
                event.addListener(fn, scope, Ext.isObject(options) ? options : {});
            }
        },

        /**
         * Removes an event handler.
         * @param {String}   eventName The type of event the handler was associated with.
         * @param {Function} handler   The handler to remove. <b>This must be a reference to the function passed into the {@link #addListener} call.</b>
         * @param {Object}   scope     (optional) The scope originally specified for the handler.
         */
        removeListener: function(ename, fn, scope) {
            var me = this,
                config,
                event,
                options;

            if (Ext.isObject(ename)) {
                options = ename;
                for (ename in options) {
                    if (options.hasOwnProperty(ename)) {
                        config = options[ename];
                        if (!me.eventOptionsRe.test(ename)) {
                            me.removeListener(ename, config.fn || config, config.scope || options.scope);
                        }
                    }
                }
            } else {
                ename = ename.toLowerCase();
                event = me.events[ename];
                if (event.isEvent) {
                    event.removeListener(fn, scope);
                }
            }
        },

        /**
         * Removes all listeners for this object including the managed listeners
         */
        clearListeners: function() {
            var events = this.events,
                event,
                key;

            for (key in events) {
                if (events.hasOwnProperty(key)) {
                    event = events[key];
                    if (event.isEvent) {
                        event.clearListeners();
                    }
                }
            }

            this.clearManagedListeners();
        },

        //<debug>
        purgeListeners : function() {
            console.warn('Observable: purgeListeners has been deprecated. Please use clearListeners.');
            return this.clearListeners.apply(this, arguments);
        },
        //</debug>

        /**
         * Removes all managed listeners for this object.
         */
        clearManagedListeners : function() {
            var managedListeners = this.managedListeners || [],
                i = 0,
                len = managedListeners.length,
                managedListener;

            for (; i < len; i++) {
                managedListener = managedListeners[i];
                managedListener.item.un(managedListener.ename, managedListener.fn, managedListener.scope);
            }

            this.managedListeners = [];
        },

        //<debug>
        purgeManagedListeners : function() {
            console.warn('Observable: purgeManagedListeners has been deprecated. Please use clearManagedListeners.');
            return this.clearManagedListeners.apply(this, arguments);
        },
        //</debug>

        /**
         * Adds the specified events to the list of events which this Observable may fire.
         * @param {Object/String} o Either an object with event names as properties with a value of <code>true</code>
         * or the first event name string if multiple event names are being passed as separate parameters.
         * @param {String} [additional] Optional additional event names if multiple event names are being passed as separate parameters.
         * Usage:<pre><code>
    this.addEvents('storeloaded', 'storecleared');
    </code></pre>
         */
        addEvents: function(o) {
            var me = this,
                args,
                len,
                i;

                me.events = me.events || {};
            if (Ext.isString(o)) {
                args = arguments;
                i = args.length;

                while (i--) {
                    me.events[args[i]] = me.events[args[i]] || true;
                }
            } else {
                Ext.applyIf(me.events, o);
            }
        },

        /**
         * Checks to see if this object has any listeners for a specified event
         * @param {String} eventName The name of the event to check for
         * @return {Boolean} True if the event is being listened for, else false
         */
        hasListener: function(ename) {
            var event = this.events[ename.toLowerCase()];
            return event && event.isEvent === true && event.listeners.length > 0;
        },

        /**
         * Suspend the firing of all events. (see {@link #resumeEvents})
         * @param {Boolean} queueSuspended Pass as true to queue up suspended events to be fired
         * after the {@link #resumeEvents} call instead of discarding all suspended events;
         */
        suspendEvents: function(queueSuspended) {
            this.eventsSuspended = true;
            if (queueSuspended && !this.eventQueue) {
                this.eventQueue = [];
            }
        },

        /**
         * Resume firing events. (see {@link #suspendEvents})
         * If events were suspended using the <code><b>queueSuspended</b></code> parameter, then all
         * events fired during event suspension will be sent to any listeners now.
         */
        resumeEvents: function() {
            var me = this,
                queued = me.eventQueue || [];

            me.eventsSuspended = false;
            delete me.eventQueue;

            Ext.each(queued,
            function(e) {
                me.fireEvent.apply(me, e);
            });
        },

        /**
         * Relays selected events from the specified Observable as if the events were fired by <code><b>this</b></code>.
         * @param {Object} origin The Observable whose events this object is to relay.
         * @param {Array} events Array of event names to relay.
         */
        relayEvents : function(origin, events, prefix) {
            prefix = prefix || '';
            var me = this,
                len = events.length,
                i = 0,
                oldName,
                newName;

            for (; i < len; i++) {
                oldName = events[i].substr(prefix.length);
                newName = prefix + oldName;
                me.events[newName] = me.events[newName] || true;
                origin.on(oldName, me.createRelayer(newName));
            }
        },

        /**
         * @private
         * Creates an event handling function which refires the event from this object as the passed event name.
         * @param newName
         * @returns {Function}
         */
        createRelayer: function(newName){
            var me = this;
            return function(){
                return me.fireEvent.apply(me, [newName].concat(Array.prototype.slice.call(arguments, 0, -1)));
            };
        },

        /**
         * <p>Enables events fired by this Observable to bubble up an owner hierarchy by calling
         * <code>this.getBubbleTarget()</code> if present. There is no implementation in the Observable base class.</p>
         * <p>This is commonly used by Ext.Components to bubble events to owner Containers. See {@link Ext.Component#getBubbleTarget}. The default
         * implementation in Ext.Component returns the Component's immediate owner. But if a known target is required, this can be overridden to
         * access the required target more quickly.</p>
         * <p>Example:</p><pre><code>
    Ext.override(Ext.form.field.Base, {
    //  Add functionality to Field&#39;s initComponent to enable the change event to bubble
    initComponent : Ext.Function.createSequence(Ext.form.field.Base.prototype.initComponent, function() {
        this.enableBubble('change');
    }),

    //  We know that we want Field&#39;s events to bubble directly to the FormPanel.
    getBubbleTarget : function() {
        if (!this.formPanel) {
            this.formPanel = this.findParentByType('form');
        }
        return this.formPanel;
    }
    });

    var myForm = new Ext.formPanel({
    title: 'User Details',
    items: [{
        ...
    }],
    listeners: {
        change: function() {
            // Title goes red if form has been modified.
            myForm.header.setStyle('color', 'red');
        }
    }
    });
    </code></pre>
         * @param {String/Array} events The event name to bubble, or an Array of event names.
         */
        enableBubble: function(events) {
            var me = this;
            if (!Ext.isEmpty(events)) {
                events = Ext.isArray(events) ? events: Ext.Array.toArray(arguments);
                Ext.each(events,
                function(ename) {
                    ename = ename.toLowerCase();
                    var ce = me.events[ename] || true;
                    if (Ext.isBoolean(ce)) {
                        ce = new Ext.util.Event(me, ename);
                        me.events[ename] = ce;
                    }
                    ce.bubble = true;
                });
            }
        }
    }, function() {
        /**
         * Removes an event handler (shorthand for {@link #removeListener}.)
         * @param {String}   eventName     The type of event the handler was associated with.
         * @param {Function} handler       The handler to remove. <b>This must be a reference to the function passed into the {@link #addListener} call.</b>
         * @param {Object}   scope         (optional) The scope originally specified for the handler.
         * @method un
         */

        /**
         * Appends an event handler to this object (shorthand for {@link #addListener}.)
         * @param {String}   eventName     The type of event to listen for
         * @param {Function} handler       The method the event invokes
         * @param {Object}   scope         (optional) The scope (<code><b>this</b></code> reference) in which the handler function is executed.
         * <b>If omitted, defaults to the object which fired the event.</b>
         * @param {Object}   options       (optional) An object containing handler configuration.
         * @method on
         */

        this.createAlias({
            on: 'addListener',
            un: 'removeListener',
            mon: 'addManagedListener',
            mun: 'removeManagedListener'
        });

        //deprecated, will be removed in 5.0
        this.observeClass = this.observe;

        Ext.apply(Ext.util.Observable.prototype, function(){
            // this is considered experimental (along with beforeMethod, afterMethod, removeMethodListener?)
            // allows for easier interceptor and sequences, including cancelling and overwriting the return value of the call
            // private
            function getMethodEvent(method){
                var e = (this.methodEvents = this.methodEvents || {})[method],
                    returnValue,
                    v,
                    cancel,
                    obj = this;

                if (!e) {
                    this.methodEvents[method] = e = {};
                    e.originalFn = this[method];
                    e.methodName = method;
                    e.before = [];
                    e.after = [];

                    var makeCall = function(fn, scope, args){
                        if((v = fn.apply(scope || obj, args)) !== undefined){
                            if (typeof v == 'object') {
                                if(v.returnValue !== undefined){
                                    returnValue = v.returnValue;
                                }else{
                                    returnValue = v;
                                }
                                cancel = !!v.cancel;
                            }
                            else
                                if (v === false) {
                                    cancel = true;
                                }
                                else {
                                    returnValue = v;
                                }
                        }
                    };

                    this[method] = function(){
                        var args = Array.prototype.slice.call(arguments, 0),
                            b, i, len;
                        returnValue = v = undefined;
                        cancel = false;

                        for(i = 0, len = e.before.length; i < len; i++){
                            b = e.before[i];
                            makeCall(b.fn, b.scope, args);
                            if (cancel) {
                                return returnValue;
                            }
                        }

                        if((v = e.originalFn.apply(obj, args)) !== undefined){
                            returnValue = v;
                        }

                        for(i = 0, len = e.after.length; i < len; i++){
                            b = e.after[i];
                            makeCall(b.fn, b.scope, args);
                            if (cancel) {
                                return returnValue;
                            }
                        }
                        return returnValue;
                    };
                }
                return e;
            }

            return {
                // these are considered experimental
                // allows for easier interceptor and sequences, including cancelling and overwriting the return value of the call
                // adds an 'interceptor' called before the original method
                beforeMethod : function(method, fn, scope){
                    getMethodEvent.call(this, method).before.push({
                        fn: fn,
                        scope: scope
                    });
                },

                // adds a 'sequence' called after the original method
                afterMethod : function(method, fn, scope){
                    getMethodEvent.call(this, method).after.push({
                        fn: fn,
                        scope: scope
                    });
                },

                removeMethodListener: function(method, fn, scope){
                    var e = this.getMethodEvent(method),
                        i, len;
                    for(i = 0, len = e.before.length; i < len; i++){
                        if(e.before[i].fn == fn && e.before[i].scope == scope){
                            e.before.splice(i, 1);
                            return;
                        }
                    }
                    for(i = 0, len = e.after.length; i < len; i++){
                        if(e.after[i].fn == fn && e.after[i].scope == scope){
                            e.after.splice(i, 1);
                            return;
                        }
                    }
                },

                toggleEventLogging: function(toggle) {
                    Ext.util.Observable[toggle ? 'capture' : 'releaseCapture'](this, function(en) {
                        if (Ext.isDefined(Ext.global.console)) {
                            Ext.global.console.log(en, arguments);
                        }
                    });
                }
            };
        }());
    });