I just spent the better part of today putting together the pieces in order to create ActiveRecord like validation in my Elixir models. Here is what I wanted to be able to do:


class Tag(Entity):
label = Field(String(200))
before_insert('validate_label')
before_update('validate_label')

def validate_label(self):
Some validation code here



I wanted to be able to write custom validation methods in my model and then hook them into sqlalchemy events like ‘before_update’ so that before any data goes to my app’s database it is first validated. Then at that point I can catch it and redirect the user to change the invalid data.

Earlier I had stumbled upon this code by Beachcoder. While I was excited to see that it could work, I was having a difficult time understanding the approach, largely because a lot of this stuff was essentially a black box to me. So I got under the hood and came up with my own approach. I’m not sure if it’s better or even complete, (even though it seems to work and I pass all my unit tests), but that’s why I am posting it here. Feedback is welcome!

from sqlalchemy.orm import MapperExtension
from elixir.statements import Statement
class HookExtension(MapperExtension):
"""
Given a hookname and a list of callbacks, (which are just methods associated with the instance)
this mapper extension overrides the given hook with a function that executes each of the callbacks.
"""
def __init__(self, hookname, callbacks):
MapperExtension.__init__(self)
def execute_callbacks(mapper, connection, instance):
for f in callbacks: getattr(instance,f)()
setattr(self, hookname, execute_callbacks)

def create_hook_statement(hookname):
“”"
A simple class generator. Given a sqlalchemy hook name like ‘before_insert’ or ‘before_update’ creates
an Elixir statement. The statement excepts a list of ‘callbacks’ which are names of methods associated
with the Elixir class that will be executed based on the hook.
“”"
class HookStatement(object):
def __init__(self, entity, *callbacks):
ext = HookExtension(hookname, callbacks)
entity._descriptor.add_mapper_extension(ext)
return HookStatement

before_insert = Statement(create_hook_statement(’before_insert’))
before_update = Statement(create_hook_statement(’before_update’))

• If you lose your job you will have to pay back the loan immediately or face severe tax penalties
• You give up the interest you would have earned had you left that money in the 401k plan for the duration of the loan
• The money you have in your 401k has not been taxed
• When you pay back your loan you are paying with after-tax dollars
• When you withdraw your money on retirement, you pay taxes again

All four statements are true and I won’t argue with any of them, and the last two statements would lead one to conclude that you are in fact faced with double-taxation. Prepare yourself for massive cognitive dissonance: 401k loans are not taxed twice!

To prepare you for the mental gymnastics ahead I have a little warm-up routine for you to follow. It’s a riddle.

Three men go to a hotel and share a room. The total cost for the room is $30, so they each give the hotel manager $10. The hotel manager later discovers that the room was actually only $25 and gives the bellhop the difference of $5 to give back to the men. The bellhop can’t think of an easy way to evenly distribute this money to the three men so he keeps two dollars for himself and gives one dollar back to each man. The men have now each paid $9 for a total of $27 and the bellhop has $2 — what happened to the other dollar?

I hope you are completely befuddled. There is in fact nothing to this riddle except a little misdirection. There is no missing dollar, I just worded the problem in a way that seemed completely logical but in fact has no bearing on the situation whatsoever. You should realize that the three men have $3, the bellhop has $2 and the hotel manager has $25 which sums up to a tidy $30.

The 401k loan problem is similar in that the last three points above are completely true but they do not help you answer the question — are 401k loans taxed twice? I will put forth two scenarios to hopefully bring some clarity to this problem. In both scenarios the man is buying a car for $20,000, he has $20,000 in his 401k and can borrow the entire amount (not true in real life, but simplifies our scenarios), he is retiring in 10 years and he earns 8% on all money he invests.

In the first scenario the man takes out a car loan for $20,000 at 9% for 48 months. He leaves the $20,000 in his 401k to earn 8%. After the loan is paid off he diverts the payments he was making on the car into the 401k for 6 years and then retires.

In the second scenario the man takes out a loan against his 401k at 6% for 48 months. At 6% his payments are less than in the first scenario, so to keep things equal he gets to invest the difference into his 401k. At the end of the 48 months he keeps putting those payments into the 401k for 6 years until he retires.

In both cases he takes out a loan. In both cases he pays back the loan with after-tax money which is the only way you can pay back loan, (I think home equity loans are an exception). The money from the loan is not taxed in both cases. As you can see, the fact that the 401k loan was taken from an account that had pre-tax money in it doesn’t even enter the equation. Again, the last three of the five truisms above that personal finance gurus often hound on aren’t even connected to this problem.

Now, which is better you ask? If you assume that your monthly payments to the 401k loan are then reinvested at 8%, the math that I did showed that the final balance of the 401k loan in the second scenario at retirement had over $10,000 more than in the first scenario. If the payments are not automatically reinvested then I don’t know what the answer is, but it’s probably not as clear cut as you might think. Remember, theoretically you can invest the difference in loan payments so if your 401k loan has a lower rate, you get to invest the difference in pre-tax dollars over the duration of the loan. You have to compare that to what your money would make if it just stayed in your 401k. I’m reluctant to make any guesses without doing the math, (I haven’t had to face this problem yet), but I suspect you’re usually better off just taking a regular loan. My energy for solving theoretical problems has officially run out, so if someone else wants to figure out whether a regular loan is better than a 401k loan assuming your payments are not reinvested immediately I think that would be a great service to everyone. In the mean time, I have the spreadsheet I used and am happy to email it to anyone on request.

I really thought that I had my finances in order. Beth and I have a cushy savings account that could cover about four months worth of expenses; we have no credit card debt and only $20,000 in student loans all of which is mostly at 3% or some other ridiculously low rate. Even still, I found myself worrying about our money, I felt like I didn’t have any control over where money was going and that the only reason we were doing well at all was because when we transitioned from college life to the working world our income more than doubled – once we adjusted to this, it seemed to me as if we would be in trouble.

I am a very organized person. This is not a natural ability of mine. In my teenage years I recognized that I needed some way to keep track of my outstanding to-dos, but about the closest I ever came to a ‘system’ was a pile of papers very neatly crammed in my backpack. I knew that the most recent stuff was at the top and so I mainly dealt with that layer. At the end of each semester I went through the pile and put anything I thought I might like to keep in my filing cabinet. Needless to say, this wasn’t the greatest system and as a result I was never very reliable.

In college I lived in a 10×10 foot room with a roommate for 2 years. That room got messy fast. I quickly learned that the only way to keep things under control was to make sure that everything had a place. It wasn’t so important to me that everything was always in its place, (remember I’m not a naturally organized person), but as long as I knew where everything should go then it never took more than 30 minutes to clean up even the worst messes. This gave me great peace of mind. When I looked at the room, Instead of thinking, “I really should clean that mess up, but it’s so much work it will have to wait”, I always knew how much work it would take to clean up, so I could decide whether I wanted to do it at that moment or later.

As it turns out, making sure that everything has a place is the key to any organizational system. When you’re organizing what’s in your head, the key is to take everything out and put it somewhere where you know you will find it at the appropriate time. If you know that everything is in your system and everything will present itself at the appropriate time so that you won’t forget – anxiety almost completely disappears. I use the GTD system created by David Allen, and I highly recommend this system to anyone.

When looking at my money situation I realized that the reason I had anxiety was because I didn’t have a place for everything – my system sucked. I decided to sit down one day and bang out something useful, and I thought I would share what I created with everyone since I think it’s incredibly useful. (Would I come up with anything that isn’t incredible? No).

The System

You will need a notepad and a copy of all your bills. The bills don’t have to be the most recent as long as it includes the date it is due and the amount. Go through each of the bills and write the due date and the amount down, also write down your paycheck amount and the corresponding dates, then order this list by date.

Now you need to decide on a fiscal period. This is fairly arbitrary, so do what makes the most sense to you but don’t think about it for too long. I picked the billing cycle of my American Express card from the 22nd to the 22nd of each month.
Now we lump our expenses into three categories:

• Automatic withdrawals, (savings, retirement, etc.)
• Fixed, recurring expenses
• Everything else

Automatic withdrawals:

I have 15% of my paycheck dumped into a savings account. Beth and I are saving for a down payment on a house, so nothing is going towards retirement at the moment. Once we’re done with the house, this will change. It’s up to you how much you save here. Here is the order that I would go in: 3-6 month emergency fund, retirement accounts, other investments. If your company offers matching on their 401k, always make that top priority.

Open up an account with Emigrant direct and set up direct deposit through your payroll department. I have two direct deposits with 85% going into my checking account and 15% going into savings.
Fixed, recurring expenses:

This is where that list of bills comes in. These bills come up every month, and they are almost always the same amount, (for utilities I just picked a number that seemed like it would almost always be more than the bill).

The goal with the list of these bills and creating a fiscal period is to make it possible to come up with one or two days that you can put on your calendar when you will pay all the bills and make sure everything is headed in the right direction. I looked at mine and it wasn’t immediately evident to me how I would accomplish this. Then I realized that I could set up automatic billing for almost all of my fixed expenses which meant that I only needed to worry about paying off my MasterCard bill on time.

Now the days I think about money are on my calendar, (remember my billing cycle is 22nd to 22nd, so these dates appear to go backwards):

The 24th, close fiscal month, (this is my process, yours may be slightly different)

• Pay American express balances
• Review assumptions in financial plan, (paychecks, monthly recurring bills, etc.), make any necessary adjustments
• Transfer money to or from to make checking account balance equal $2300. This is enough to cover recurring fixed expenses: MasterCard bill (this are all my automatic bills, we don’t carry a balance), student loans, electric bill, rent + $300 pad. I will need to pay much of this before the first paycheck of my billing cycle. This may require some adjusting up front to get to this initial balance, but after one month there should not be too much adjusting.
• Set up any automatic transfers to occur for planned future expenses. For example, you want to buy a $200 bookshelf in two months, you set up an automatic transfer to secondary savings account for $100 to occur twice. Adjust your available spending cash for the month. You are treating saving like a bill that must be paid. (More on this later).

The 13th

• Pay MasterCard balance

Everything Else

Add up your recurring fixed expenses and subtract that from your monthly income, (You’re income is your original paycheck minus all of the behind the scenes automatic withdrawals). Don’t spend more than that amount. That’s it. What, no budget? I don’t think people really need a budget. I think the only useful thing a budget does is force you to allocate all of your money – this way you know how much you can spend. This of course naturally reduces anxiety but it is a huge amount of overhead. Why do I need to know how much money I can spend on books? I only allocated $15 per month but I really want to buy that $22 dollar book but it will put me over budget! Screw that. I can spend $1200 a month. I know between gas and food, I typically have about $500 left. I have a pretty good feel for how much I have to spend, I can also check my American express balance and see if I’m headed up too quickly – if that’s the case then I just slow down my spending. Easy.

If you want to purchase a relatively big ticket item, (I would say over $100 falls into this category), treat it like a fixed, recurring expense. That’s what the fourth bullet above is describing. Pay $50/month into your savings account for two months, then you can buy your $100 thing. “But I really want that $300 oak vanity now!” or “But I owe $900 for car insurance next week because I forgot to plan for it!” Okay, give yourself a loan. I’m assuming you have 3-6 months of savings, pull it from there, charge yourself 5%, and create a loan payment in the fixed, recurring bills category. Keep in mind that with any of this, it is subtracted from what you can spend each month, so you will have to spend less money to by that vanity.

What have I left out?

Let me know! It seems to me as if this covers everything. I don’t really need to think about my money except once a month I do a high level check and every couple of days or so I check my American Express balance to monitor my day-to-day spending. My anxiety levels around money have disappeared.

If such a scenario exists, and we are in Everyone-Else, is it useful for us to spend any time thinking about Heaven? Of course not, because we can’t affect Heaven and Heaven can’t affect us. In this case we can’t prove that Heaven doesn’t exist – but who cares, because it can’t even change one atom of this universe. This is a useless definition of Heaven, because we can’t even get there.

If we change the scenario and say you can go to Heaven, but you can’t come back, then this starts to look like a fairly common description of life after death as defined by Christians. When a Christian dies his or her sole soul leaves Everyone-Else and goes to Heaven and never comes back, (none of that reincarnation bologna). On the way to Heaven, the sole is stripped of sin which can’t ever enter Heaven.

By going to Heaven, we have taken something away from Everyone-Else — our soul. If this is the case, we should be able to measure this transfer of energy and prove that there is life after death. If there is nothing to measure, then there is no life after death.

It is impossible to create any version of life after death, any version of Heaven that does not at least in some way create a measurable effect. If it’s not measurable or observable, then it doesn’t exist and it is like the first scenario. If Heaven can’t interact with us in any way then it is pointless to think about or speculate on the existence of Heaven. If Heaven can interact with us then we can measure it and observe it – and therefore it is part of this universe. If life after death exists we can prove it.

We can take this logic and apply it to everything that we as Christians speculate exists – if it has the ability to affect the universe then we can prove it exists. If it doesn’t affect the universe, and can’t ever affect the universe, then we can’t prove that it doesn’t exist – but it also has absolutely no effect on the universe, so who cares?

The Good

The Q has a lot of upside.

Price: At $200 with the purchase of a new Verizon plan, the price can’t be beat. If you buy it at full retail, it comes with the slightly heftier price tag of $500. Compare this to similar offerings and you will find it is still a very modest price.

Form Factor: The Q fits nicely into the palm of your hand. Although its width initially had me concerned, that feeling quickly passed as soon as I realized how easily it fit into my shirt pocket. It’s also slips comfortably into normal pants pockets and its presence is not as easily detected as the clamshell models I previously preferred.

One drawback I see with the shape of the Q is that when using it as a phone, a wide portion of the screen is pressed against your cheek, and so it is constantly smudged.

The Keyboard: The Q is the first phone of its class with a full QWERTY keyboard. Responding to email, text messages and entering data is a breeze. There are a few problems and drawbacks with the keyboard. The keys are rather hard plastic and are not very comfortable — I have a texture phobia and these keys do not help matters. I have a feeling normal people won’t care. Also, you will never be able to text IDOL04 to vote for Taylor Hicks because the letters underneath the numbers do not line up the same way as on a traditional phone. You’ll have to ask your non-Q owning friends to help you out.

Smartphone Software: This phone can accomplish almost anything you need it to accomplish. Keep in mind that the Q does not have a touch screen — it’s a Smartphone not a Pocket PC. This means that you can’t edit documents since only the Pocket PC software will allow you to do that. The Q is the first Smartphone with a QWERTY keyboard, and as such it is the first Smartphone where the ability to edit documents would actually be a useable feature. I have a feeling this ability will be available as a software update in the near future. In the meantime, even though you can’t edit them, you can view virtually any document.

If you are not happy with the out of the box functionality there are hundreds of Windows Mobile 5.0 compatible third-party applications to take advantage of. For instance, I am using Oxios ToDo list in order to use my Q in my Getting Things Done (GTD) system. (More on GTD in a future post). I also highly recommend AgileMobile for instant messaging. Watch out though, it drains the battery quickly.

Email is easy to get going. I use ActiveSync to sync with Accenture’s exchange servers for work, and I just use the built-in browser to access Google’s mobile web interface to check my Gmail account.

Miscellaneous: The Q also has: built in Bluetooth, a slot for MiniSD memory (I bought a gig for $60), voice notes recorder, excellent media player, pretty good camera, (I actually use it vs. didn’t even bother with previous phones), and very good voice quality. It excels at its basic function as a phone.

The Bad

It’s certainly not perfect.

Smartphone Software: I know this made the list of pros, but something has to be said about the negative aspects of the phone’s software. There are a wide ranging set of user interface problems associate with the Windows Mobile Smartphone software. Basically, it’s not as well thought-out as Palm software so you click through more submenus then you should rightfully have to.

Email: Again, this was a pro overall, but as of now you can’t set the Motorola Q to accept push email. I think this feature will be available soon as a software upgrade, but for now you’ll have to settle for checking your email every 5 minutes. I suppose this would be an acceptable interim solution, if it weren’t for the…

Battery Life: The Q sucks the battery dry when you are using it as a phone. I’ve found I have approximately 3-4 hours of talking time. When I’m primarily using the data features and not the voice features, the battery easily lasts all day. If you are on the phone a lot and not near a charger, this is not a good phone for you. My life consisted of a series of stressful and long phone calls in the last few weeks before my wedding, so I am very familiar with the poor battery life of the Q. On the bright side, the battery life has gotten better over the past few months, so I can skip charging at night every once in a while — but this is risky so I don’t recommend it. Also, I noted significant improvement in battery life when I set my email to sync manually. Syncing every 5 minutes drained the battery quickly.

The Data Plan: $45/month for less than DSL speeds is just too much. You can’t get the Q without a data plan. I guess you can, but you really shouldn’t. The Q assumes you have a plan and doesn’t ever warn you if you are about to use the data network. Expect to see charges for accessing Verizon’s data network on your bill each month even if you have gone out of your way to not use the data services. Don’t get a Q without a data plan.

Conclusion

In general I am extremely pleased with this phone. It accomplishes exactly what I want. I recognize that it is not as powerful as a bigger and chunkier Treo 650 or similar Pocket PC devices, but I also felt it was more important to have something that was truly mobile and didn’t make me feel like tightening my belt to keep my pants on when I put it in my pocket. I can check my email and respond. I can view attachments. I can create voice notes, take pictures, read my Bloglines account, chat with my friends on AIM and Google Chat, watch videos, listen to music and place phone calls. The best part is that all of this functionality slips into my shirt pocket for $200. It may not be the iPod of Smartphones, but I thinks it is a glimpse into the future of our mobile lifestyle.

]]> http://www.planningforaliens.com/2006/09/05/motorola-q-review/feed/ http://www.planningforaliens.com/2006/08/29/how-to-install-tortoisesvn/ http://www.planningforaliens.com/2006/08/29/how-to-install-tortoisesvn/#comments Tue, 29 Aug 2006 20:26:26 +0000 Sean http://www.planningforaliens.com/?p=7 1. Open up your web browser to the TortoiseSVN downloads page.

2. Scroll down until you see a post entitled “The current version is…” and download the file that ends with the .msi extension under the 32 bit subheading. It will look something like the following, but the numbers could be different: TortoiseSVN-1.3.5.6804-svn-1.3.2.msi

3. You will be directed to a screen with a list of locations and download links on the right side. Scroll down until you see the location nearest you, in my case it is Phoenix, AZ.

Download the file to your desktop or where you can find it easily.

4. Once the file completes downloading, open it and click through the wizard. There are no special options, just keep clicking ‘next’ until you can click ‘install’. You will have to reboot your computer to finish the installation.

5. Once your computer has finished rebooting, TortoiseSVN is now installed. Right click anywhere on your desktop and you will now see two additional options: SVN checkout and TortoiseSVN.

6. Now we need to adjust the configuration settings. Right click anywhere on your desktop and within the TortoiseSVN submenu choose “Settings…”

7. Highlight “General” and click the “Edit” button next to the words “Subversion configuration file”

8. Delete everything in that file and insert the following:

Note: Ensure that there is no leading white space, (tabs or spaces), in your file when you cut and paste the selection below.

[auth]
[helpers]
[tunnels]
[miscellany]
enable-auto-props = yes
[auto-props]
* = svn:needs-lock=*

9. Save your changes and close out all of the TortoiseSVN windows currently open.

10. Open up My Documents and create a new folder. If you are following these directions, I have sent you an email with some information. Name the new folder the same as the name of the repository that is within that email.

11. Right click on your new folder and choose “SVN checkout”. In the “URL of repository” field enter http://meshsandbox.com/svn/(the name of your repository). Leave everything else and click OK.

12. Enter in the username and password I provided you. Make sure and choose the option to save the name and password, otherwise you will be entering it in quite frequently.

You have successfully installed subversion and checked out a working copy of your repository. Chances are there are no files in your repository, so let’s add one for practice:

1. If you have a file that you know you want to be under version control, drag it into the folder we have just created. For future reference this folder is called the “Working Copy”.

2. Even though you see the file in the folder, it is still not in the repository. As you recall from this article, what you have on your computer is merely a copy of all the files held within the repository. Anyone with access to the repository has a copy of it and it is up to you to update the real repository with any changes you have made. Right click on the document, go into the TortoiseSVN menu and choose “Add”.

3. The file is now part of the repository, but now you need to committ your changes. Right click anywhere within the window and choose “SVN Commit”. This will permanently save your changes to the repository. Now, whenever anyone checks out or updates the repository, they will have your file.

I will create another set of directions to clarify these last few steps. I have also created a screen cast that illustrates how to check out the repository and add a file as described above. You can view it here. I recommend clicking on the icon with the double boxes located in the bottom right corner of the video box to expand it to full screen.

You can also download the zipped windows media file here if you want a clearer picture.

What is Subversion? Subversion is version control software. Version control helps a group of people manage a set of shared files.

For example:

You are working on a presentation with three other people. You go home and after watching an inspirational television program you feel the urge to update the slides. Just before you head off to bed, you email the new presentation to everyone on your team. At the same time another member of your team also updated the slides and emailed their changes to everyone. The next morning when you check your email you have two separate versions of your presentation and the joyless task of merging both sets of changes into one version. Version control solves this problem.

All files controlled by Subversion are stored in a repository. This is basically a digital vault that everyone on your team can access from anywhere with an internet connection. Each person who has access to the repository maintains an updated copy of all the files on their computer: this is called your “working copy”. Each person has their own copy. Once you are done working, you update the version stored in the vault. This is called, “committing” your changes. The next time someone on your team updates their working copy it will contain your changes and they will be working on the most recent “version” of the file. This is why it’s called “version” control.

As of Subversion 1.2 you can now lock files. When one member of the team locks the file, no other team member can make changes to the file. In our example above, you would have locked the presentation before you started making changes, so the other member of your team couldn’t have made changes to the document.

I’ve created a workflow diagram to show the process you would use to update a file when it is under version control using Subversion.

Note: Using Subversion it is possible to have multiple people working on one file at the same time. Subversion would then merge the changes and pass off any complicated conflicts to a human. However, it can’t do this with complicated files like Microsoft Word, Excel or Powerpoint. This is why the repositories I am creating for my friends and family will be set up to require locks as I have described above.

Planning for Aliens will be a reflection of what I am thinking about at the moment. It will catalogue the progression of my thoughts and ideas. I doubt this blog will never generate the kind of traffic Meshsandbox did because it will not be focused like a laser on one topic and it will not be full of useful information. Nevertheless, I am really happy to be blogging again.