@qooxdoo/framework
Version:
The JS Framework for Coders
250 lines (222 loc) • 7.59 kB
JavaScript
/* ************************************************************************
qooxdoo - the new era of web development
http://qooxdoo.org
Copyright:
2004-2012 1&1 Internet AG, Germany, http://www.1und1.de
License:
MIT: https://opensource.org/licenses/MIT
See the LICENSE file in the project's top-level directory for details.
Authors:
* Martin Wittemann (wittemann)
************************************************************************ */
/**
* Basic implementation for an event emitter. This supplies a basic and
* minimalistic event mechanism.
*/
qx.Bootstrap.define("qx.event.Emitter", {
extend: Object,
statics: {
/** Static storage for all event listener */
__storage: []
},
members: {
__listener: null,
__any: null,
/**
* Attach a listener to the event emitter. The given <code>name</code>
* will define the type of event. Handing in a <code>'*'</code> will
* listen to all events emitted by the event emitter.
*
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
* @return {Integer} An unique <code>id</code> for the attached listener.
*/
on(name, listener, ctx) {
var id = qx.event.Emitter.__storage.length;
this.__getStorage(name).push({
listener: listener,
ctx: ctx,
id: id,
name: name
});
qx.event.Emitter.__storage.push({
name: name,
listener: listener,
ctx: ctx
});
return id;
},
/**
* Attach a listener to the event emitter which will be executed only once.
* The given <code>name</code> will define the type of event. Handing in a
* <code>'*'</code> will listen to all events emitted by the event emitter.
*
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
* @return {Integer} An unique <code>id</code> for the attached listener.
*/
once(name, listener, ctx) {
var id = qx.event.Emitter.__storage.length;
this.__getStorage(name).push({
listener: listener,
ctx: ctx,
once: true,
id: id
});
qx.event.Emitter.__storage.push({
name: name,
listener: listener,
ctx: ctx
});
return id;
},
/**
* Remove a listener from the event emitter. The given <code>name</code>
* will define the type of event.
*
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
* @return {Integer|null} The listener's id if it was removed or
* <code>null</code> if it wasn't found
*/
off(name, listener, ctx) {
var storage = this.__getStorage(name);
for (var i = storage.length - 1; i >= 0; i--) {
var entry = storage[i];
if (entry.listener == listener && entry.ctx == ctx) {
storage.splice(i, 1);
qx.event.Emitter.__storage[entry.id] = null;
return entry.id;
}
}
return null;
},
/**
* Removes the listener identified by the given <code>id</code>. The id
* will be return on attaching the listener and can be stored for removing.
*
* @param id {Integer} The id of the listener.
* @return {Integer|null} The listener's id if it was removed or
* <code>null</code> if it wasn't found
*/
offById(id) {
var entry = qx.event.Emitter.__storage[id];
if (entry) {
this.off(entry.name, entry.listener, entry.ctx);
}
return null;
},
/**
* Alternative for {@link #on}.
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
* @return {Integer} An unique <code>id</code> for the attached listener.
*/
addListener(name, listener, ctx) {
return this.on(name, listener, ctx);
},
/**
* Alternative for {@link #once}.
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
* @return {Integer} An unique <code>id</code> for the attached listener.
*/
addListenerOnce(name, listener, ctx) {
return this.once(name, listener, ctx);
},
/**
* Alternative for {@link #off}.
* @param name {String} The name of the event to listen to.
* @param listener {Function} The function execute on {@link #emit}.
* @param ctx {var?Window} The context of the listener.
*/
removeListener(name, listener, ctx) {
this.off(name, listener, ctx);
},
/**
* Alternative for {@link #offById}.
* @param id {Integer} The id of the listener.
*/
removeListenerById(id) {
this.offById(id);
},
/**
* Emits an event with the given name. The data will be passed
* to the listener.
* @param name {String} The name of the event to emit.
* @param data {var?undefined} The data which should be passed to the listener.
*/
emit(name, data) {
var storage = this.__getStorage(name).concat();
var toDelete = [];
for (var i = 0; i < storage.length; i++) {
var entry = storage[i];
entry.listener.call(entry.ctx, data);
if (entry.once) {
toDelete.push(entry);
}
}
// listener callbacks could manipulate the storage
// (e.g. module.Event.once)
toDelete.forEach(
function (entry) {
var origStorage = this.__getStorage(name);
var idx = origStorage.indexOf(entry);
origStorage.splice(idx, 1);
}.bind(this)
);
// call on any
storage = this.__getStorage("*");
for (var i = storage.length - 1; i >= 0; i--) {
var entry = storage[i];
entry.listener.call(entry.ctx, data);
}
},
/**
* Returns the internal attached listener.
* @internal
* @return {Map} A map which has the event name as key. The values are
* arrays containing a map with 'listener' and 'ctx'.
*/
getListeners() {
return this.__listener;
},
/**
* Returns the data entry for a given event id. If the entry could
* not be found, undefined will be returned.
* @internal
* @param id {Number} The listeners id
* @return {Map|undefined} The data entry if found
*/
getEntryById(id) {
for (var name in this.__listener) {
var store = this.__listener[name];
for (var i = 0, j = store.length; i < j; i++) {
if (store[i].id === id) {
return store[i];
}
}
}
},
/**
* Internal helper which will return the storage for the given name.
* @param name {String} The name of the event.
* @return {Array} An array which is the storage for the listener and
* the given event name.
*/
__getStorage(name) {
if (this.__listener == null) {
this.__listener = {};
}
if (this.__listener[name] == null) {
this.__listener[name] = [];
}
return this.__listener[name];
}
}
});