Le mardi 26 juillet 2011 11:52:10, Andreas Hocevar a écrit :
> Hi Richard,
>
Hi Andreas,
> Also, please let me know if you're able to override constructors in 2.11
> with this approach:
>
> var A = OpenLayers.Class({...});
> var B = OpenLayers.Class(A, {...});
>
> OverloadB = {
> initialize: function() {...},
> customMethod: function() {...},
> customProperty: "foo"
> };
> var BTemp = OverloadB.initialize;
> BTemp.prototpye = B.prototype;
> OpenLayers.Util.extend(BTemp.prototype, OverloadB);
> B = BTemp;
>
Based on this, I have modified and tested overloading in both OL 2.10 and OL
2.11 and its works for both !
The final code looks like (sure it can be improved) :
/**
* Function: OpenLayers.overload
* Apply the patch to the given class and propagate it downward
* to the sub-classes by insuring that only not overwritten
* methods() or properties are overloaded.
*
* Parameters:
* P - {Object} an instance of {<OpenLayers.Class>}
* F - {Object} an object used to overwrite methods (including
* constructor) and properties of P and its sub-classes.
*
* Returns:
* {Object} the overloaded instance of given {<OpenLayers.Class>}
*/
OpenLayers.overload= function(P,F) {
//save old class
var xProto= OpenLayers.Util.extend({},P.prototype);
var X= {};
for (var xn in P) {
var p= P[xn];
if (typeof(p)=="function" && p.prototype.initialize) {
// clean P from sub-classes ...
delete P[xn];
X[xn]= p;
}
}
//save overload object to prevent overriding of initialize method in it
var f= OpenLayers.Util.extend({},F);
var pTemp= null;
// protect initializer from sub-classes overloading :
if (typeof(F.initialize)=="function") {
pTemp= function() { F.initialize.apply(this,arguments); };
delete f["initialize"];
} else {
var initialize= P.prototype.initialize;
pTemp= function() { initialize.apply(this,arguments); };
delete P.prototype["initialize"];
}
pTemp.prototype= P.prototype;
OpenLayers.Util.extend(pTemp.prototype, f);
P= pTemp;
// restore sub-classes:
// propagate constructor/properties/method to sub-class ...
for (var xn in X) {
var p= X[xn];
delete X[xn];
if (typeof(p)=='function') {
if (p.prototype.initialize) {//ensure it is a Class
f= OpenLayers.Util.extend({},F);
// check for overloaded properties :
for (var fn in F) {
var fp= F[fn];
if (typeof(fp)=="function") {
if (p.prototype[fn]===xProto[fn]) {
// override method ...
continue;
}
delete f[fn];
continue;
}
if (p.prototype.hasOwnProperty(fn) &&
xProto.hasOwnProperty(fn) && fp!==undefined) {
if (p.prototype[fn]===xProto[fn]) {
// override property ...
continue;
}
delete f[fn];
continue;
}
}
// override sub-class :
var x= p;
var c= OpenLayers.Class(P,p.prototype);
for (var cn in x) {
var xp= x[cn];
delete x[cn];
if (typeof(xp)=='function' && xp.prototype.initialize)
{//ensure it is a Class
c[cn]= xp;
}
}
x= null;
P[xn]= OpenLayers.overload(c,f);
}
} else {
P[xn]= p;
}
}
xProto= null;
X= null;
return P;
};
Many thanks for your help.
> Andreas.
didier
--
RICHARD Didier - Chef du pôle technique du Géoportail
2/4, avenue Pasteur - 94165 Saint Mandé Cedex
Tél : +33 (0) 1 43 98 83 23
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