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Static class variables in Python

Is it possible to have static class variables or methods in python? What syntax is required to do this?

Why are exclamation marks used in Ruby methods?

In Ruby some methods have a question mark (?) that ask a question like include? that ask if the object in question is included, this then returns a true/false.

But why do some methods have exclamation marks (!) where others don't?

What does it mean?

Getting the name of the current executing method

Is there a way to get the name of the currently executing method in Java?

Python: Why do some functions have underscores "__" before and after the function name?

This seems to occur a lot, and was wondering if this was a requirement in the Python languages, or merely a matter of convention.

Also, could someone name and explain which functions tend to have the underscores, and why (__init__, for instance)?

Adding a Method to an Existing Object Instance

I've read that it is possible to add a method to an existing object (e.g. not in the class definition) in Python, I think this is called Monkey Patching (or in some cases Duck Punching). I understand that it's not always a good decision to do so. But, how might one do this?

UPDATE 8/04/2008 00:21:01 EST:

That looks like a good answer John Downey, I tried it but it appears that it ends up being not a true method. Your example defines the new patch function with an argument of self, but if you write actual code that way, the now patched class method asks for an argument named self (it doesn't automagically recognize it as the object to which it is supposed to bind, which is what would happen if defined within the class definition), meaning you have to call class.patch(obj) instead of just class.patch() if you want the same functionality as a true method. It looks like Python isn't really treating it as a method, but more just as a variable which happens to be a function (and as such is callable). Is there any way to attach an actual method to a class?

Oh, and Ryan, that isn't exactly what I was looking for (it isn't builtin functionality), but it is quite cool nonetheless.

Should C# methods that *can* be static be static? [closed]

Should C# methods that can be static be static?

We were discussing this today and I'm kind of on the fence. Imagine you have a long method that you refactor a few lines out of. The new method probably takes a few local variables from the parent method and returns a value. This means it could be static.

The question is: should it be static? It's not static by design or choice, simply by its nature in that it doesn't reference any instance values.

Method Syntax in Objective C

Can someone explain this method declaration syntax for me? In this function, the number of rows of a UIPickerView (slot machine UI on the iPhone) is being returned. From my understanding, the Method is called 'pickerView', and returns an NSInteger.

It passes in a pointer to the UIPickerview called 'pickerView' ... first, why is the method called the same name as the parameter?

Next there is NSInteger parameter called component that tells us which component we are counting the rows for. The logic to decide which is in the body of the method.

What is 'numberOfRowsInComponent? It seems to describe the value we are returning, but it is in the middle of the parameters.

- (NSInteger) pickerView:(UIPickerView *)pickerView 
 numberOfRowsInComponent:(NSInteger)component
{
    if (component == kStateComponent)
    	return [self.states count];

    return[self.zips count];
}

Final arguments in interface methods - what's the point?

In Java, it is perfectly legal to define final arguments in interface methods and do not obey that in the implementing class, e.g.:

public interface Foo {
    public void foo(int bar, final int baz);
}

public class FooImpl implements Foo {

    @Override
    public void foo(final int bar, int baz) {
        ...
    }
}

In the above example, bar and baz has the opposite final definitions in the class VS the interface.

In the same fashion, no final restrictions are enforced when one class method extends another, either abstract or not.

While final has some practical value inside the class method body, is there any point specifying final for interface method parameters?

Why can't I declare static methods in an interface?

The topic says the most of it - what is the reason for the fact that static methods can't be declared in an interface?

public interface ITest {
    public static String test();
}

The code above gives me the following error (in Eclipse, at least): "Illegal modifier for the interface method ITest.test(); only public & abstract are permitted".

Cannot refer to a non-final variable inside an inner class defined in a different method

Edited: I need to change the values of several variables as they run several times thorugh a timer. I need to keep updating the values with every iteration through the timer. I cannot set the values to final as that will prevent me from updating the values however I am getting the error I describe in the initial question below:

I had previously written what is below:

I am getting the error "cannot refer to a non-final variable inside an inner class defined in a different method".

This is happening for the double called price and the Price called priceObject. Do you know why I get this problem. I do not understand why I need to have a final declaration. Also if you can see what it is I am trying to do, what do I have to do to get around this problem.

public static void main(String args[]) {

    int period = 2000;
    int delay = 2000;

    double lastPrice = 0;
    Price priceObject = new Price();
    double price = 0;

    Timer timer = new Timer();

    timer.scheduleAtFixedRate(new TimerTask() {
        public void run() {
            price = priceObject.getNextPrice(lastPrice);
            System.out.println();
            lastPrice = price;
        }
    }, delay, period);
}

How to find where a method is defined at runtime?

We recently had a problem where, after a series of commits had occurred, a backend process failed to run. Now, we were good little boys and girls and ran rake test after every check-in but, due to some oddities in Rails' library loading, it only occurred when we ran it directly from Mongrel in production mode.

I tracked the bug down and it was due to a new Rails gem overwriting a method in the String class in a way that broke one narrow use in the runtime Rails code.

Anyway, long story short, is there a way, at runtime, to ask Ruby where a method has been defined? Something like whereami( :foo ) that returns /path/to/some/file.rb line #45? In this case, telling me that it was defined in class String would be unhelpful, because it was overloaded by some library.

I cannot guarantee the source lives in my project, so grepping for 'def foo' won't necessarily give me what I need, not to mention if I have many def foo's, sometimes I don't know until runtime which one I may be using.

How to check whether an object has certain method/property?

Using dynamic pattern perhaps? You can call any method/property using the dynamic keyword, right? How to check whether the method exist before calling myDynamicObject.DoStuff(), for example?

What's wrong with using $_REQUEST[]?

I've seen a number of posts on here saying not to use the $_REQUEST variable. I usually don't, but sometimes it's convenient. What's wrong with it?

Is it wrong to use Deprecated methods or classes in Java?

I am using eclipse to develop a web application. Just today I have updated my struts version by changing the JAR file. I am getting warnings at some places that methods are deprecated, but the code is working fine.

I want to know some things

1. Is it wrong to use Deprecated methods or classes in Java?

2. What if I don't change any method and run my application with warnings that I have, will it create any performance issue.

List view getListItemXmlAttributes method fails with child publication items

I have created a JS class to populate SG/Folder list view data, when items are modified. (As per Jaime's approach) Everything works great when I operate on items in the publication they're created in.

Ex: I open a component or page and the custom locked by column immediately updates and shows my user name.

However, when I go to a child publication and repeat that process, I get the window asking if I want to localize or edit the parent item. If I select to edit the parent window, the code doesn't work. I haven't quite figured it out yet with initial debugging. Chrome seems to swallow the error, Firefox gives me a cryptic:

Timestamp: 6/22/2012 3:42:54 PM

Error: uncaught exception: [Exception... "Component returned failure code: 0x80004002 (NS_NOINTERFACE) [nsIWebProgress.DOMWindow]" nsresult: "0x80004002 (NS_NOINTERFACE)" location: "JS frame :: chrome://browser/content/tabbrowser.xml :: :: line 545" data: no]

Does anyone have any initial ideas? I'll try to post some code later on...

Code from PageEx.js:

Type.registerNamespace("MyCompany.Tridion.RTFExtensions");

/*
* Constructor
*/

MyCompany.Tridion.RTFExtensions.PageEx = function (id) {
    Type.enableInterface(this, "MyCompany.Tridion.RTFExtensions.PageEx");
    this.addInterface("Tridion.ContentManager.Page", [id]);
    var p = this.properties;
    p.versionNumberString = undefined;
    p.modifiedBy = undefined;
    p.lockedBy = undefined;
    p.approvalStatus = undefined;
    p.publishDate = undefined;
    p.previousVersion = undefined;
    p.previousApprovalStatus = undefined;
    p.customModifiedDate = undefined;
    p.initialModifierUserName = undefined;
};

/*
* sends the list xml string for the item 
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.getListItemXmlAttributes = function (customAttributes) {
    var attribs = {};
    $extUtils.getListItemXmlAttributes(customAttributes,this, attribs);
    return this.callBase("Tridion.ContentManager.Page", "getListItemXmlAttributes", [attribs]);
};


/*
* This method gets called when an item is opened from list view. node parameter has the information
* displayed in the list view as attributes. We are getting cutom data extender column information 
* from this xml node and storing it in this class member for returning it from getListItemXmlAttributes method
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.setDataFromList = function (node, parentId, timeStamp) {
    $extUtils.setDataFromList(node,parentId,timeStamp,this);
    this.callBase("Tridion.ContentManager.Page", "setDataFromList", [node, parentId, timeStamp]);
};

/* 
* Gets item icon 
*/
MyCompany.Tridion.RTFExtensions.PageEx.prototype.getItemIcon = function () {
    var icon = this.callBase(this.defaultBase, "getItemIcon");
    return icon;
};

Code from utils.js:

// reloads the list view for the given id (used in list view data refresh when JS cant get the required data without reloading)
MyCompany.Tridion.RTFExtensions.Utilities.reloadListView = function (listTcmId) {
    var registry = $models.getListsRegistry();
    for(var key in registry)
    {
        var entry = $models.getItem(registry[key]);
        if (entry && entry.getParentId() == listTcmId)
        {
           entry.unload();
           return true;
        }
    }
    return false;
}

/*
* This method gets called when an item is opened from list view. node parameter has the information
* displayed in the list view as attributes. We are getting cutom data extender column information 
* from this xml node and storing it in this class member for returning it from getListItemXmlAttributes method
*/
MyCompany.Tridion.RTFExtensions.Utilities.setDataFromList = function (node, parentId, timeStamp, itemClicked) {
    var p = itemClicked.properties;

    if (!timeStamp || timeStamp > itemClicked.getTimeStamp()) {
        var tmp;
        if (tmp = node.getAttribute('Version')) {
            p.versionNumberString = tmp;
            p.previousVersion = tmp;
        }
        if (tmp = node.getAttribute('ModifiedBy')) {
            p.modifiedBy = tmp;
            p.initialModifierUserName = tmp;
        }
        if (tmp = node.getAttribute('LockedBy')) {
            p.lockedBy = tmp;
        }
        if (tmp = node.getAttribute('ApprovalStatus')) {
            p.approvalStatus = tmp;
            p.previousApprovalStatus = tmp;
        }
        if (tmp = node.getAttribute('PublishDate')) {
            p.publishDate = tmp;
        }
        if (p.customModifiedDate === undefined) {
            if (tmp = node.getAttribute('Modified')) {
                p.customModifiedDate = tmp;
            }
        }
    }
}

/*
* sends the list xml string for the item in the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListItemXmlAttributes = function (customAttributes, listViewObject,attribs) {
    var p = listViewObject.properties;
    $extUtils.getListViewItemLockedByName(p,listViewObject);

    if (customAttributes) {
        for (var attr in customAttributes) {
            attribs[attr] = customAttributes[attr];
        }
    }

    attribs["Version"] = $extUtils.getListViewItemUpdatedVersion(p,listViewObject);
    //modified name has to come after the version update...
    $extUtils.getListViewItemModifiedByName(p,listViewObject);
    attribs["ApprovalStatus"] = $extUtils.getListViewItemApprovalStatus(p,listViewObject);  
    attribs["PublishDate"] = $extUtils.getListViewItemPublishDate(p,listViewObject);

    //set default values
    if (p.versionNumberString != undefined) {
        var iResult = p.versionNumberString.localeCompare(p.previousVersion);
        if (p.previousVersion === undefined || iResult > 0) {
            //it's been updated!
            p.previousVersion = p.versionNumberString;
            p.previousApprovalStatus = p.approvalStatus;

            //also need to update modified date
            p.customModifiedDate = $extUtils.getListViewItemUpdatedModifiedDate(p,listViewObject);
            p.initialModifierUserName = p.modifiedBy;
        }

    }
    attribs["Modified"] = p.customModifiedDate;
    attribs["LockedBy"] = p.lockedBy;
    attribs["ModifiedBy"] = p.modifiedBy;

};

/*
* This method sets the property of the Revisor owner on the item in the list view. however, if it's not the current user
* we have no way to look that up in JS so we have to reload the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemModifiedByName = function (p,listViewObject) {
    var p = listViewObject.properties;
    var xmlDoc = listViewObject.getXmlDocument();
    if (xmlDoc) {
        //modifier should always exist...
        var modifierId = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Revisor/@xlink:title");
        if (modifierId != undefined) {
            var u = Tridion.UI.UserSettings.getJsonUserSettings(true);
            if (modifierId == u.User.Data.Name) {
                var strDescription = u.User.Data.Description.split('(');
                p.modifiedBy = strDescription[0];
                return;
            } else {
                //we're in trouble...
                //let's hope it's the initial modifier we had...
                if (p.previousVersion == p.versionNumberString) {
                    //whew...
                    p.modifiedBy = p.initialModifierUserName;
                    return;
                }

                if (!$extUtils.reloadListView(listViewObject.getOrganizationalItemId())) {
                    //hrm. something failed on the reload? not sure what else to do:
                    p.modifiedBy = modifierId;
                }
            }
        } else {
            //shouldn't ever happen.
            p.modifiedBy = "";
            return;
        }
    }

};

/*
* This method sets the property of the lock owner on the item in the list view. however, if it's not the current user
* we have no way to look that up in JS so we have to reload the list view.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemLockedByName = function (p,listViewObject) {
    var xmlDoc = listViewObject.getXmlDocument();
    if (xmlDoc) {
        //this will be user id. no sense getting tcmid... can't look it up without async call
        var lockedUserId = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:ItemLock/tcm:User/@xlink:title");
        if (lockedUserId != undefined) {
            //see if it's the current user. most likely...
            var u = Tridion.UI.UserSettings.getJsonUserSettings(true);
            if (lockedUserId == u.User.Data.Name) {
                var strDescription = u.User.Data.Description.split('(');
                p.lockedBy = strDescription[0];
                return;
            }
            //it's not the current user. no synch way to do what we want, plus the JS call doesn't get the workflow version anyway. refresh the parent view
            if (!$extUtils.reloadListView(listViewObject.getOrganizationalItemId())) {
                //hrm. something failed on the reload? not sure what else to do:
                p.lockedBy = lockedUserId;
            }
        } else {
            //clear it out since there's no lock owner
            p.lockedBy = "";
        }
    }
};

/*
* Gets the ApprovalStatus from the item
* This makes absolutely no sense... but for some reason the approval status gets wiped out when this method
* enters. so I had to use a "previous approval status" variable to maintain it. no idea why. I don't see anything
* else that should be touching it... but clearly something clears it out.
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemApprovalStatus = function (p,listViewObject) {
    //check if the item has actually been modified.
    if (p.versionNumberString != p.previousVersion) {
        var xmlDoc = listViewObject.getXmlDocument();
        if (xmlDoc) {
            p.approvalStatus = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:Data/tcm:ApprovalStatus/@xlink:title");
        }
    } else {
        p.approvalStatus = p.previousApprovalStatus;
    }
    if (p.approvalStatus === undefined || p.approvalStatus.toUpperCase() == 'UNAPPROVED') {
        var foo = p.approvalStatus;
        p.approvalStatus = 'WIP';
    }
    return p.approvalStatus;
};


/*
* Gets the PublishDate from the item list view
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemPublishDate = function (p,listViewObject) {
    //modification won't alter publish date.
    var p = listViewObject.properties;
    return p.publishDate;
};


/*
*   get the modified date for the workflow version, overwrite OOB since that uses last major version
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemUpdatedModifiedDate = function (p,listViewObject) {
    var xmlDoc = listViewObject.getXmlDocument();
    var modDate = $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:RevisionDate");
    return modDate;
}


/*
* Gets the updated Version information from the item
*/
MyCompany.Tridion.RTFExtensions.Utilities.getListViewItemUpdatedVersion = function (p,listViewObject) {
    var p = listViewObject.properties;
    var xmlDoc = listViewObject.getXmlDocument();
    var newVersionString = undefined;
    if (xmlDoc) {
        newVersionString = String.format("{0}.{1}", $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Version"), $xml.getInnerText(xmlDoc, "/tcm:*/tcm:Info/tcm:VersionInfo/tcm:Revision"));
    }
    if (newVersionString != undefined) {
        //want to ensure we're getting a LATER version than we had (because it will try to load the non-workflow version afterwards...
        var iResult = newVersionString.localeCompare(p.previousVersion);
        if (p.previousVersion === undefined || iResult > 0) {
            p.versionNumberString = newVersionString;
        } else {
            p.versionNumberString = p.previousVersion;
        }
    } else {
        p.versionNumberString = p.previousVersion;
    }
    return p.versionNumberString;
};



function launchPopup(winURL, winName, winFeatures, winObj) {
    // this will hold our opened window
    var theWin;
    // first check to see if the window already exists
    if (winObj != null) {
        // the window has already been created, but did the user close it?
        // if so, then reopen it. Otherwise make it the active window.
        if (!winObj.closed) {
            winObj.focus();
            return winObj;
        }
        // otherwise fall through to the code below to re-open the window
    }
    // if we get here, then the window hasn't been created yet, or it
    // was closed by the user.
    theWin = window.open(winURL, winName, winFeatures);
    return theWin;
}

var $extUtils = MyCompany.Tridion.RTFExtensions.Utilities;