20 Oct 2016
These days, I’m a bit annoyed about Java generics. Because it seems that when you want to be clean, you pretty
much always get in troubles.
I’ll give you an example. The method to create a mock with EasyMock is currently typed like this:
public static <T> T mock(Class<T> toMock)
This seems quite straightforward.
But it is also quite annoying to use. For example, let’s try to mock a generic type:
List<String> list = mock(List.class);
It looks like something we would like to easily do but you get this nice warning:
Warning:(51, 33) java: unchecked conversion
required: java.util.List<java.lang.String>
found: java.util.List
And there’s no way to get around it. Here are some attempts:
List<String> list = mock(List<String>.class); // no allowed (won't compile)
List<String> list = EasyMock.<String>mock(List.class); // won't compile either because the parameter type doesn't match)
List<String> list = (List<String>) mock(List.class); // still get a warning
So what’s the way out?
To be less accurate.
Yes. I can’t see any other way out. (Do you?)
So my plan is to change EasyMock typing with this:
public static <T> T mock(Class<?> toMock)
No relation anymore between the parameter and the returned type. WAT!!! Are you crazy?!?
So yes, this will compile without complaints :-( (but I can check the type coherence at runtime)
String list = mock(Integer.class);
But this will now work without any warning :-)
List<String> list = mock(List.class);
You can’t have your cake and eat it it seems. But as usual, I will be happy to be proved wrong.
18 Sep 2016
My favorite stress tool has been Gatling for many years now.
Scenarios are
- Easy to construct, It’s just code
- Easy to version. It’s just code
- Easy to run. It’s a simple command line that you launch in remote if needed
- Having great result graphs
- Easy to datamine. There is a
simulation.log file that let’s you do some more digging when needed
My only complaints are
- You can’t change the running scenario
- It’s in Scala
The first one might be addressed by Gatling Frontline. I haven’t tried.
The second one is a bit more complicated to solve :-)
In fact, I don’t care that’s in Scala. But I would love to be able to core my scenario in Java.
So just for fun, I did a thought experiment. I’ve coded the Gatling API in Java and then coded the BasicScenario
example using this API.
It’s not working for real
The API is just an emply shell. To know how different it would be from the Scala DSL.
The answer is: Not much.
My expectations were that I would need to rely on plenty of Java 8 features to get something close
to the Scala DSl. But in fact, not even.
The main differences are:
- Variables are typed
- I’ve added a
build method. But it’s just for style. I can get rid of it
- A bunch of semi-colons
- No syntactic sugar to create a map
- I’m using
Duration is used to time units
- I need a
run method where the setUp method is
That’s quite joyful and probably can be improved.
I’m now wondering if I could have used the Scala classes directly. I’m not good at making Java and Scala
interacting.
So if someone is and want to try, please do so.
16 Feb 2016
If you are like me, you tend to work on open source using your personal email and at YP using your enterprise email. But
git doesn’t handle that well so you need to never forget to do
git config user.email henri.tremblay@somewhere.com
after each git init or git clone.
I finally had the time for work on an almost satisfying solution.
07 Sep 2015
This version has finally removed the old (and ugly) partial mocking methods. You are now required to use the
partialMockBuilder.
In exchange, you get really nice short methods to create your mocks: mock, niceMock and strictMock.
You also get a better stability since cglib and ASM are now embedded to remove a possible version mismatch with
your own dependencies. Note that Objenesis will stay as an explicit dependency.
Change log
11 Jun 2015
Now that Objenesis is in Bintray. The goal was to also have EasyMock binaries at the same place. They were hosted on SourceForge. And as you might have read,
SourceForge
is
now on the dark side so going out of there was becoming a priority.
This time it was easier. I basically made a list of versions and release dates.
And then I made a loop around the lines to the
- wget to get the binary and store it keeping the SourceForge structure
- curl to create the version in Bintray
- curl to upload the binary
I've manually added the release notes in GitHub but wasn't able to figure out how to push them to Bintray. If someone knows, please tell me.
To be helpful, here is the loop that I used to create the versions.
API_KEY=xxx
PASSPHRASE=xxx
# This is because I want the file upside down to create the older versions first
tail -r $1 > tmp.tsv
while read p; do
version=$(echo "$p" | cut -d' ' -f1)
date=$(echo "$p" | cut -d' ' -f2)
version=${version// /-}
echo $version $date
content="{ \"name\": \"$version\", \"desc\": \"$version\", \"released\": \"${date}T00:00:00.000Z\", \"github_use_tag_release_notes\": false, \"vcs_tag\": \"$version\" }"
echo "$content"
curl -v -XPOST -H "Content-Type: application/json" -H "X-GPG-PASSPHRASE: ${PASSPHRASE}" -uhenri-tremblay:${API_KEY} \
-d "$content" \
https://api.bintray.com/packages/easymock/distributions/easymock/versions
done <tmp.tsv
03 Jun 2015
Following my previous article,
I will now describe the Jira migration of EasyMock to GitHub issue tracker.
EasyMock Jira was on Codehaus.
So I had to migrate it somewhere else.
Instead of migrating to another Jira instance I’ve decided that EasyMock doesn’t need all that complexity anymore and that going to Github would enough.
The migration was made in two steps:
- Save everything on my disk
- Import everything in GitHub
22 May 2015
I'm inaugurating a new section that will be more life oriented i.e not talking about software engineering. It might be in English or French depending on my mood and the public expected to read the entry. So this first blog post is more or less an open letter to
The Economist.
When I'm not doing software engineering, I'm highly interested in finance, economy and politics. Until recently, I was even a diligent subscriber of The Economist. I've decided two months ago to not renew my subscription. Not because I don't like the magazine anymore but because it was too time consuming to read. I want this year to have the time to read books.
I was receiving the paper version which allows me to have access to the online version. Of course, I'm not keeping the paper versions in my basement since I was having access to them online. I was really surprised to realize that as soon as my subscription expired, I've lost the access to the entire The Economist website content. Event the editions
THAT I PAID FOR!
I found that to be quite a cheap decision from a journal as renowned as The Economist.
But I also think it shouldn't be legal. It's been one of my thoughts for a while now.
Virtual properties should have the same "rights" as physical ones. When I buy a physical book, I can sale it, lend it, give it.
If an buy a e-book, I can't do all this. I'm locked in whatever rules the seller wants to apply. And I don't feel good about it. I'm pretty sure I'm not the only one and I'm also pretty sure it creates adoption issues.
Of course you can buy virtual gears. Sellers love to sell you stuff. Virtual or not. But when it's virtual, they currently make sure you will never really be the owner of it.
Yes, I do understand the concept of service. For instance, The Economist offers the website as a service to their customer. They pay the hosting, the development so it makes sense that if I stop paying, the service stops. But it doesn't make sense that I can't download the PDF of all the issues I bought. Of course it means that I would then be allowed to illegally diffuse them. But I can allow photocopy my paper issue. Or scan it.
Meanwhile, I'm left with a bitter taste in my mouth. Until these's a law protecting my virtual properties, I'm not really sure I will trust The Economist anymore.
18 May 2015
With Codehaus and Google Code
closing, I’m happily required to migrate Objenesis and EasyMock.
Both projects have an hybrid hosting using different platforms. I’ve decided to start with Objenesis which is easier to
migrate. I’ll describe the process in this post. Hopefully, it will be helpful to someone but, in fact, I’m also looking
forward to your feedback to see if I can improve my final setup.
So, Objenesis source code was originally on Google Code. I’ve moved it to GitHub some years ago mainly because pull
requests are awesome. The website is also a GitHub page. Part of the documentation is on Google Code wiki, the binaries
are on Google Code as well as the issue tracker.
Google being nice folks, they used to provide a nice way (https://code.google.com/export-to-github, now down) to migrate everything
to GitHub. But I couldn’t use that because
- I don’t want the project to end up in
henri-tremblay/objenesis. I want it where it is now, in the
EasyMock organisation
- I only want to migrate the wiki and the issues since the sources are already there
So here’s what I did instead.
Issue tracker
The issue tracker was migrated using the IssueExporterTool.
It worked perfectly (but is a bit slow as advertised).
Wiki pages
At first, I tried to export the entire Objenesis project to Github to be able to retrieve the wiki pages and then move them
to the real source code. The result was quite bad because the tables are not rendered correctly. So I ended up manually
migrating each page to markdown. There was only 3 pages so it wasn’t too bad.
Binaries
This was more complicated. Maven binaries are already deployed through the Sonatype Nexus. But I needed to migrate the
standalone bundles. I’ve looked into three options:
- GitHub releases
- Bintray
- Both (GitHub releases exported to Bintray)
GitHub releases are created automatically when you tag in git. But you also seem to be able to add some release notes and
binaries over that. I didn’t want to dig too much into it. I knew I wanted to be in Bintray in the end. And I wanted easy
automation. Bintray was easy to use so I went for Bintray only. Be aware, the way I did the migration is low-tech (but works).
- Make a list of all the binaries to migrate
- Get them with
wget https://objenesis.googlecode.com/files/objenesis-xxx.zip
- Create an organisation, a distribution repository and
an [objenesis package])(https://bintray.com/easymock/distributions/objenesis) in Bintray
- Add my GPG key to my Bintray account
- Upload everything using REST (
curl -T objenesis-xxx.zip -H "X-GPG-PASSPHRASE: ${PASSPHRASE}" -uhenri-tremblay:${API_KEY} https://api.bintray.com/content/easymock/distributions/objenesis/xxx/objenesis-xxx-bin.zip?publish=1)
It works, the only drawback is that no release notes are provided. They’ve always been on the website
Project moved
Finally, I’ve set the “Project Moved” flag to target GitHub. This quite aggressively
redirects you to GitHub if you try to access https://code.google.com/p/objenesis.
26 Mar 2015
When creating this blog, the first thing I wanted to talk about are those things you learn everyday when fighting on a technical issue. Because if it happened to me, it will probably happen to you.
What I discover is that a lot of these things are too small to be a blog post or will in fact just repeat a really nice existing blog post where I found my answer in the first place. And a blog post just telling you to read another blog post is not that useful.
Instead, I've decided to tweet these blog posts each time I fell on one. I'll use the
#WhatILearnedToday hashtag. If you're interested, you can then
follow me on Twitter.
See ya!
21 Mar 2015
But time consuming. So always remember that I should have, for instance, read the assembly generated code to be able to explain why an implementation is faster than another. But I don't have that kind of time right now. So I was just toying around.
Anyway, a friend of mine has replaced a bunch of
String.replaceAll with a way longer but way faster implementation based on a for loop. I was happy about it.
To make a long story short, it has bounced a bit around the internet and has created an
official challenge on github. All this is well
resumed (in French) by Olivier Croisier on his blog.
Since I have an interest in performance tuning, I've started to play with it. Being annoying, instead of providing my own implementation, I first had a look at the benchmark implementation itself. Done with
JMH (always reassuring to see a benchmark that isn't home made).
So, first I asked for unit tests for make sure my implementations were accurate. Then I've extracted the benched methods in a specific class. At first, it was a static class inside the JMH benchmark. JMH is rewriting this class into something else. To be safe, I prefer to put the benched code where it will be for real.
After that, I notice an issue. The dataset used was randomly generated at the beginning of the benchmark. So each benched method was receiving a different dataset. Not good to make comparable results. We are now generating a dataset first and then run all benchmarks on it.
Finally, I wanted the dataset to be representative of a real file. Some I made some statistics on a real file to get the usual length of lines, occurence of line feeds, etc. This allowed me to change the generator to create a better result.
Now I was set. I must confess, my best result is a plain copy of
Cédric Champeau's solution with a tiny tuning. I made sub-methods. On my machine (OS X Yosemite, 2.6 GHz Intel Core i7, Java HotSpot 64 bits 1.8.0_40), it's 10% faster. On
Travis, it's not that conclusive.
Anyway, now the funny part is that I tried lots of things that should have been more efficient but that are not.
- Putting the pattern of the regex in a constant should be faster than only recreating it all the time. No. Pretty much the same result
- Adding the missing else in two subsequent ifs should prevent a comparison and be faster. No. It's almost slower
- Using the ternary operator instead of a if can be a bit faster. But not much. But it is different.
- Removing a ++ that was redundant doesn't change anything
- Use a new array instead of cloning and then writing over a single array. This removes a huge copy. But it's slower. Probably because of page faults.
- Using arraycopy instead of assigning every single character. Much slower
- Using Unsafe to retrieve, allocate and assign. Also much slower. But I'm pretty sure I can improve this one
As I said, I've not tried to explain the results. I'm just assuming they are valid. Please don't do this at home.
However, if the results are indeed valid, it seems that the JVM optimisations give counter-intuitive results. Sometime, doing more things if in fact faster.
And of course, if you want to try the challenge, it's open to all :-)