If I put the check in a static block, then the check is only done once
on startup, right? Is this acceptable, or is it frowned upon because
it adds a slight penalty to the startup even if the developer never
uses the function.
Something like,
static {
ensureGetElementsByClassNameRegistered();
}
private static native void ensureGetElementsByClassNameRegistered() {
if (!document.getElementsByClassName) {
document.getElementsByClassName = function(element, class) {
// etc
}
}
}
On Sat, Apr 18, 2009 at 3:54 AM, Ray Cromwell <[email protected]> wrote:
>
> You don't want to create a separate property just for native
> getElementsByClassName() as that would almost double the number of
> permutations (except IE where is it known not to exist) What you
> could provide is 3 implementations. IE gets raw DOM version,
> Safari/Firefox/Opera get a version that checks
> if(document.getElementsByClassName) exists, and if not, falls back to
> document.evaluate.
>
> -Ray
>
>
> On Fri, Apr 17, 2009 at 11:03 PM, Vitali Lovich <[email protected]> wrote:
>>
>> Do you have any suggestions regarding how to do the proper deferred
>> binding for the various versions? Should I just put the typical JS
>> check that regular libraries use? (i.e. if
>> (!document.getElementsByClassName) { // provide fallback }. I thought
>> the whole point of deferred binding was to get around that.
>>
>> What is the list of officially supported browsers? In particular the
>> specific minimum version for each?
>>
>> I guess I'm going to have to install a virtual machine for this
>> because Safari refuses to work in wine 1.0.19 - chrome is useable
>> although no HTTPS sites.
>>
>> Is there a guide somewhere on writing & integrating the tests into
>> GWT, or just look at existing ones in the source.
>>
>> On Sat, Apr 18, 2009 at 1:49 AM, Miroslav Pokorny
>> <[email protected]> wrote:
>>>
>>> Provide some tests and make sure it works on all officially supported
>>> browsers even if the implementation is suboptimal. There are many js
>>> libs out there so it's not hard to find the best way to do it fir the
>>> various browsers...
>>>
>>> On 18/04/2009, at 12:39 PM, Vitali Lovich <[email protected]> wrote:
>>>
>>>> Just my first attempt at adding some initial support for
>>>> getElementsByClassName. This is by no means tested or
>>>>
>>>> Newer browsers support getElementsByClassName. This is my attempt
>>>> at a patch.
>>>>
>>>> Caveats:
>>>> There's a "bug" in that quirks mode doesn't behave properly (I don't
>>>> know how to detect it in the deferred binding) for IE & Firefox2 &
>>>> earlier. According to the HTML5 spec, it's supposed to be case
>>>> insensitive in quirks mode. However, this "bug" behaves the exact
>>>> same way as all the javascript wrappers do (since I based the XPath &
>>>> RegExp code paths roughly around the implementations floating out
>>>> there).
>>>>
>>>> I'm also not sure if I added the support correctly for Firefox.
>>>> getElementsByClassName only came in with FF3 & requires the xpath
>>>> workaround for FF2 & earlier (I believe I read xpath was introduced
>>>> with FF 1.5). I placed the xpath code in DOMImplMozillaOld for now
>>>> (not sure whether or not gecko1_8 represents FF2).
>>>>
>>>> There's also no mention of the versions of Safari & Opera that are
>>>> supported by GWT, so they're defaulting to using the native version
>>>> (which will not work if they don't provide it).
>>>>
>>>> Safari in particular got it with version 3.1. if earlier versions are
>>>> supported, it's not too much work. Simply grab the expression built
>>>> in the FF xpath & pass it to document._getElementsByXPath(query,
>>>> parent) for Safari versions that have xpath (not sure which those
>>>> are). Not sure how to distinguish Safari pre3.1 & post3.1 in deferred
>>>> binding.
>>>>
>>>> Opera got it with 9.5. Not sure when xPath support got into Opera
>>>> (should be a straightfoward copy of the mozilla code). Not sure how
>>>> to distinguish the two in the deferred binding.
>>>>
>>>> Feedback would be appreciated.
>>>>
>>>> Should this go as an enhancement request in the issue tracker?
>>>>
>>>> >
>>>> diff --git a/user/src/com/google/gwt/dom/client/DOMImpl.java b/user/
>>>> src/com/google/gwt/dom/client/DOMImpl.java index 1d7e39b..581764b
>>>> 100644 --- a/user/src/com/google/gwt/dom/client/DOMImpl.java +++ b/
>>>> user/src/com/google/gwt/dom/client/DOMImpl.java @@ -176,6 +176,8 @@
>>>> abstract class DOMImpl { return 0; }-*/; + public abstract NodeList
>>>> getElementsByClassName(Element parent, String className); + public
>>>> native Element getFirstChildElement(Element elem) /*-{ var child =
>>>> elem.firstChild; while (child && child.nodeType != 1) diff --git a/
>>>> user/src/com/google/gwt/dom/client/DOMImplIE6.java b/user/src/com/
>>>> google/gwt/dom/client/DOMImplIE6.java index 04c205a..8c24a6c 100644
>>>> --- a/user/src/com/google/gwt/dom/client/DOMImplIE6.java +++ b/user/
>>>> src/com/google/gwt/dom/client/DOMImplIE6.java @@ -15,6 +15,8 @@ */
>>>> package com.google.gwt.dom.client; +import
>>>> com.google.gwt.core.client.JsArray; + /** * Internet Explorer 6
>>>> implementation of * {...@link com.google.gwt.user.client.impl.DOMImpl}.
>>>> @@ -184,6 +186,31 @@ class DOMImplIE6 extends DOMImpl { } @Override
>>>> + public NodeList getElementsByClassName(Element parent, String
>>>> className) { + // TODO: detect quirks mode so that the regexps do a
>>>> case insensitive match as per the + // spec. when quirks mode
>>>> detected, pass "i" as the flags parameter + return
>>>> getElementsByClassName(parent, className.split(" "), "").cast(); + }
>>>> + + private native JsArray getElementsByClassName(Element parent,
>>>> String [] classes, String flags) /*-{ + var i, j, e, c, elements =
>>>> parent.all || parent.getElementsByTagName("*"); + var regexps = [],
>>>> result = []; + for (i = classes.length - 1; i >= 0; i--) { + c =
>>>> classes[i].replace(/^\s+|\s+$/g, ""); + if (c.length) +
>>>> regexps.push(new RegExp(new Array("(?:^|\\s)", c, "(?:\\s|
>>>> $)").join(""), flags); + } + if (regexps.length) { + for (i = 0, c =
>>>> elements.length; i < c; i++) { + e = elements[i]; + for (j =
>>>> regexps.length - 1; j >= 0 && regexps[j].test(e); j--) {} + j == -1
>>>> && result.push(e); + } + } + return result; + }-*/; + + @Override
>>>> public native String getInnerText(Element elem) /*-{ return
>>>> elem.innerText; }-*/; diff --git a/user/src/com/google/gwt/dom/
>>>> client/DOMImplMozillaOld.java b/user/src/com/google/gwt/dom/client/
>>>> DOMImplMozillaOld.java index ecf52fb..5fd7312 100644 --- a/user/src/
>>>> com/google/gwt/dom/client/DOMImplMozillaOld.java +++ b/user/src/com/
>>>> google/gwt/dom/client/DOMImplMozillaOld.java @@ -15,6 +15,8 @@ */
>>>> package com.google.gwt.dom.client; +import
>>>> com.google.gwt.core.client.JsArray; + /** * DOM implementation
>>>> differences for older version of Mozilla (mostly the * hosted mode
>>>> browser on linux). The main difference is due to changes in @@
>>>> -114,4 +116,23 @@ package com.google.gwt.dom.client; return top +
>>>> viewport.scrollTop; }-*/; + + @Override + public NodeList
>>>> getElementsByClassName(Element parent, String className) { + // the
>>>> cast should be safe since both it & JsArray access the underlying
>>>> object the same way + // and NodeList is immutable (constraints
>>>> added, not removed) + return getElementsByClassName(parent,
>>>> className.split(" ")).cast(); + } + + private native JsArray
>>>> getElementsByClassName(Element parent, String [] classes) /*-{ + var
>>>> result, i, xpathResult, classExpr = ".//*"; + for (i =
>>>> classes.length - 1; i >= 0; i--) { + classExpr +=
>>>> "[contains(concat(' ', @class, ' '), ' " + classes[i] + " ')]"; + }
>>>> + xpathResult = document.evaluate(classExpr, parent, null, 0, null);
>>>> + while ((i = xpathResult.iterateNext())) { + result.push(i); + } +
>>>> return result; + }-*/; } diff --git a/user/src/com/google/gwt/dom/
>>>> client/DOMImplStandard.java b/user/src/com/google/gwt/dom/client/
>>>> DOMImplStandard.java index 90d2e89..be29fe1 100644 --- a/user/src/
>>>> com/google/gwt/dom/client/DOMImplStandard.java +++ b/user/src/com/
>>>> google/gwt/dom/client/DOMImplStandard.java @@ -114,6 +114,11 @@
>>>> abstract class DOMImplStandard extends DOMImpl { }-*/; @Override +
>>>> public native NodeList getElementsByClassName(Element parent, String
>>>> className) /*-{ + return parent.getElementsByClassName(className);
>>>> + }-*/; + + @Override public native boolean isOrHasChild(Element
>>>> parent, Element child) /*-{ return parent.contains(child); }-*/;
>>>> diff --git a/user/src/com/google/gwt/dom/client/Document.java b/user/
>>>> src/com/google/gwt/dom/client/Document.java index 209b1b9..23d6daf
>>>> 100644 --- a/user/src/com/google/gwt/dom/client/Document.java +++ b/
>>>> user/src/com/google/gwt/dom/client/Document.java @@ -1125,6 +1125,18
>>>> @@ public class Document extends Node { }-*/; /** + * Returns a
>>>> {...@link NodeList} of all the {...@link Element Elements} with a given +
>>>> * class name in the order in which they are encountered in a
>>>> preorder traversal + * of the document tree. + * + * @param
>>>> className the space-separated name of the classes to match on + *
>>>> @return a list containing all the matched elements. + */ + public
>>>> final NodeList getElementsByClassName(String className) { + return
>>>> DOMImpl.impl.getElementsByClassName(this.cast(), className); + } +
>>>> + /** * Returns the {...@link Element} whose id is given by elementId.
>>>> If no such * element exists, returns null. Behavior is not defined
>>>> if more than one * element has this id. diff --git a/user/src/com/
>>>> google/gwt/dom/client/Element.java b/user/src/com/google/gwt/dom/
>>>> client/Element.java index a0bf9f2..d64b83e 100644 --- a/user/src/com/
>>>> google/gwt/dom/client/Element.java +++ b/user/src/com/google/gwt/dom/
>>>> client/Element.java @@ -149,6 +149,18 @@ public class Element
>>>> extends Node { }-*/; /** + * Returns a {...@link NodeList} of all the
>>>> {...@link Element Elements} with a given + * class name in the order in
>>>> which they are encountered in a preorder traversal + * of this
>>>> elements children. + * + * @param className the space-separated
>>>> names of the classes to match on + * @return a list containing all
>>>> the matched elements. + */ + public final NodeList
>>>> getElementsByClassName(String className) { + return
>>>> DOMImpl.impl.getElementsByClassName(this, className); + } + + /** *
>>>> Returns a NodeList of all descendant Elements with a given tag name,
>>>> in the * order in which they are encountered in a preorder traversal
>>>> of this Element * tree.
>>>
>>> >
>>>
>>
>> >
>>
>
> >
>
--~--~---------~--~----~------------~-------~--~----~
http://groups.google.com/group/Google-Web-Toolkit-Contributors
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