[25160] | 1 | /*
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| 2 | * file: MVC.js
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| 3 | *
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| 4 | * @BEGINLICENSE
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| 5 | * Copyright 2010 Brook Novak (email : [email protected])
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| 6 | * This program is free software; you can redistribute it and/or modify
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| 7 | * it under the terms of the GNU General Public License as published by
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| 8 | * the Free Software Foundation; either version 2 of the License, or
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| 9 | * (at your option) any later version.
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| 10 | * This program is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 13 | * GNU General Public License for more details.
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| 14 | * You should have received a copy of the GNU General Public License
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| 15 | * along with this program; if not, write to the Free Software
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| 16 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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| 17 | * @ENDLICENSE
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| 18 | */
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| 19 | bootstrap.provides("MVC");
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| 20 |
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| 21 | /**
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| 22 | * Extends the given instance into a model (wrt MVC).
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| 23 | *
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| 24 | * @param {Object} subject The subject containing model data to be observed.
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| 25 | */
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| 26 | function _model(subject) {
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| 27 |
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| 28 | // The list of registered observers for this subject
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| 29 | var observers = [],
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| 30 | observersToRemove; // Zeroed/undef when not firing event, array when model is firing event.
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| 31 |
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| 32 | $extend(subject, {
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| 33 |
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| 34 | /**
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| 35 | *
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| 36 | * Notifies all observers that a specific event occured.
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| 37 | *
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| 38 | * @param {String} event The event name to fire (excluding the "on" prefix).
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| 39 | * For example, "KeyDown" would invoke "onKeyDown" in all observers
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| 40 | *
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| 41 | * @param {Object} details Optional custom details data
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| 42 | */
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| 43 | fireEvent: function(event){
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| 44 |
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| 45 | if (observers.length > 0) {
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| 46 |
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| 47 | // Construct additional arguments array
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| 48 | var i,
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| 49 | observer,
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| 50 | remObservers,
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| 51 | args = Array.prototype.slice.call(arguments);
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| 52 |
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| 53 | args.shift();
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| 54 |
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| 55 | // Flag this model as firing
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| 56 | observersToRemove = [];
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| 57 |
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| 58 | // Fire events on each observer
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| 59 | for (i in observers) {
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| 60 | observer = observers[i];
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| 61 |
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| 62 | // If the observer has declared a listener function for this event invoke it
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| 63 | if (typeof observer.ref["on" + event] == "function")
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| 64 | observer.ref["on" + event].apply(observer.context, args);
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| 65 | }
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| 66 |
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| 67 | // Reset flag
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| 68 | remObservers = observersToRemove;
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| 69 | observersToRemove = 0;
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| 70 |
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| 71 | // If Observers when trying to remove themself during an event fire
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| 72 | // then safely remove them now.
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| 73 | for (i in remObservers) {
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| 74 | this.removeObserver(remObservers[i]);
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| 75 | }
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| 76 |
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| 77 | }
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| 78 | },
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| 79 |
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| 80 | /**
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| 81 | * Adds an observer for receiving event notifications.
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| 82 | * If the observer already exists in the observer set it will not be added twice.
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| 83 | *
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| 84 | * @param {Object} observer An observer to add to the set.
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| 85 | *
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| 86 | * @param {Object} context (Optional) The context at which the events should be invoked in.
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| 87 | * Will default to the observer object.
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| 88 | *
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| 89 | * @param {Boolean} notifiedFirst (Optional) True to be the first observer to be notified in the current list.
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| 90 | * Otherwise it will be added to the end of the list
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| 91 | */
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| 92 | addObserver: function(observer, context, notifiedFirst){
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| 93 |
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| 94 | // Ensure that observer array is a set
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| 95 | if (observerIndex(observer) != -1)
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| 96 | return;
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| 97 |
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| 98 | // Create observer instance
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| 99 | observer = {
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| 100 | ref : observer,
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| 101 | context : context || observer
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| 102 | };
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| 103 |
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| 104 | // Add to list depending on requested order
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| 105 | if (notifiedFirst) observers.unshift(observer);
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| 106 | else observers.push(observer);
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| 107 |
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| 108 | },
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| 109 |
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| 110 | /**
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| 111 | * Removes an observer from the subjects observer list.
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| 112 | *
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| 113 | * @param {Object} observer An observer to remove from the set
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| 114 | */
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| 115 | removeObserver: function(observer) {
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| 116 |
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| 117 | // Avoid removing observers while in a firing-event state since some browsers
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| 118 | // may miss firing an event on a observer if the observer list is sliced while iterating the list
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| 119 | if (observersToRemove)
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| 120 | observersToRemove.push(observer); // Will be removed after firing of events finished
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| 121 |
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| 122 | else {
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| 123 | var index = observerIndex(observer);
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| 124 | if (index >= 0) observers.splice(index, 1);
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| 125 | }
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| 126 | }
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| 127 | });
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| 128 |
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| 129 | /**
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| 130 | * @param {Object} observerRef The observer reference to check
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| 131 | *
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| 132 | * @return {Number} The index in the observers array at which observerRef exists.
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| 133 | * -1 if not found.
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| 134 | */
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| 135 | function observerIndex(observerRef) {
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| 136 | for (var i = 0; i < observers.length; i++) {
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| 137 | if (observers[i].ref == observerRef)
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| 138 | return i;
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| 139 | }
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| 140 | return -1;
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| 141 | }
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| 142 |
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| 143 | }
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| 144 |
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| 145 | /**
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| 146 | * Exposure of model internal
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| 147 | * @see _model
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| 148 | */
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| 149 | de.model = _model;
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| 150 |
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