All streams

Multithreading

Now let’s talk about thin ice. In the previous sections about IDisposable we touched one very important concept that underlies not only the design principles of Disposable types but any type in general. This is the object’s integrity concept. It means that at any given moment of time an object is in a strictly determined state and any action with this object turns its state into one of the variants that were pre-determined while designing a type of this object. In other words, no action with the object should turn it into an undefined state. This results in a problem with the types designed in the above examples. They are not thread-safe. There is a chance the public methods of these types will be called when the destruction of an object is in progress. Let’s solve this problem and decide whether we should solve it at all.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

Span<T> usage examples

A human by nature cannot fully understand the purpose of a certain instrument until he or she gets some experience. So, let’s turn to some examples.

ValueStringBuilder

One of the most interesting examples in respect to algorithms is the ValueStringBuilder type. However, it is buried deep inside mscorlib and marked with the internal modifier as many other very interesting data types. This means we would not find this remarkable instrument for optimization if we haven’t researched the mscorlib source code.

What is the main disadvantage of the StringBuilder system type? Its main drawback is the type and its basis — it is a reference type and is based on char[], i.e. a character array. At least, this means two things: we use the heap (though not much) anyway and increase the chances to miss the CPU cash.

Another issue with StringBuilder that I faced is the construction of small strings, that is when the resulting string must be short e.g. less than 100 characters. Short formatting raises issues on performance.

This chapter was translated from Russian jointly by author and by professional translators. You can help us with translation from Russian or English into any other language, primarily into Chinese or German.

Also, if you want thank us, the best way you can do that is to give us a star on github or to fork repository github/sidristij/dotnetbook.

In 2013, while working at GFRANQ photo service, I participated in the development of an eponymous web service for publishing and processing photos. Filters and transformations were defined in the file with parameters, and all processing was carried out on the server. During service development, there was a need to support these transformations on the client side for the preview. According to Larry Wall, one of the virtues of a programmer is laziness. Therefore, as truly lazy programmers, we thought about the possibility of using the same code on both the server and client sides. The entire development was conducted in C#. After researching the libraries and a couple of attempts, we proudly concluded that this was possible and began to write the universal code.

Why is this article needed? Indeed, 6 years have passed since 2013, and many technologies have lost their relevance, for example, Script#. On the other hand, new ones have appeared. For example, Bridge.NET or Blazor based on the fancy WebAssembly.

Nevertheless, some ideas can still be used. In this article I tried to describe them as detailed as possible. I hope that the mention of Silverlight and Flash will cause a smile with a hint of nostalgia, and not a desire to criticize the old solutions. Anyway, they have contributed to the development of the web industry.

I made the “electric” designer of… cardboard. Alas, the project still remains at the prototype stage, not developing into an industrial “physical” look and is waiting for its time (and investor).

But I decided to go further — once we started making cardboard, we’ll bring the situation to its logical conclusion — we’ll make a complete cardboard board game, but with an electric setting and a learning effect. There were a lot of options — starting from a simple “walker” and ending with Ameritrash from a zombie with electron movement and vicious short circuits and swollen capacitors.

As a result, I decided to dwell on a logical abstract, since the schematics of electrical circuits are very suitable for it. Said and done — as a result of the first iteration, the game “Circuit” was born.

Introduction & Recap

In the previous blog post, we learned how to move our current application into a Master-Detail app displaying Business Partner as a list (master) and its detail information with Sale Orders inside the detail page (detail).

What will be covered on this exercise

With Part 4 of this series of blog posts, we will learn how to create a second drill-down page with information about the Sale Order detail and display a table of Sale Order items.

The most important part of this exercise is to understand how to Delete (part of the CRUD operations) a Sale Order Item of a Sale Order.

• ODataModel: we have already used it to display server-side information about our Business Partner, Order Sale. Now we’re going to use it to display Sale Order Item and delete them from the set. For this purpose, we’re going to use the remove method

This is our main task in this exercise but it’s not the only thing we’ve done in the code. Here’s a list of the things you have to do to get to the final result:

• Add a new route and target in the manifest.json to navigate to the BusinessPartnerSeleOrderItem page
• Listen on the Sale Order click event and navigate to the SaleOrder detail (where we will display sale order detail and sale order items)
• Add a FilterBar to filter the Sale Order Item’s table
• Add a ViewSettingsDialog to sort/group Sale Order Items
• Expand the ToProduct navigation property of a SaleOrderItem entity to display Product information into table’s rows

Trace Compass with GZip

Trace Compass is an open-source application performance analysis framework. It is designed to visualize and analyze traces, which are recordings of events that occur in a software system during its execution. Trace Compass is particularly useful for understanding the behavior, performance, and interactions within complex software systems.

Key features of Trace Compass include:

Trace Visualization: It provides a graphical representation of traces, allowing users to visualize the sequence and timing of events in a system.

Analysis Tools: Trace Compass offers various analysis tools and modules for different types of traces, helping users identify performance bottlenecks, errors, and other issues.

Support for Multiple Trace Formats: It supports a wide range of trace formats from different sources, making it versatile for analyzing traces generated by various software components.

Customizable Views: Users can customize the views and analyses based on their specific needs, allowing for a more tailored and effective analysis process.

Integration with Eclipse: Trace Compass is often integrated with the Eclipse IDE, providing developers with a seamless environment for analyzing and debugging their applications.

Overall, Trace Compass is a valuable tool for developers, system administrators, and performance analysts to gain insights into the runtime behavior of software systems and optimize their performance.

All the credit is due to the RFC’s authors: A. Azimov (Qrator Labs & Yandex), E. Bogomazov (Qrator Labs), R. Bush (IIJ & Arrcus), K. Patel (Arrcus), K. Sriram.

A BGP route leak is an unintentional propagation of BGP prefixes beyond the intended scope that could result in a redirection of traffic through an unintended path that may enable eavesdropping or traffic analysis, and may or may not result in an overload or complete drop (black hole) of the traffic. Route leaks can be accidental or malicious but most often arise from accidental misconfigurations.

The National Internet Segment Reliability Research explains how the outage of a single Autonomous System might affect the connectivity of the impacted region with the rest of the world. Generally, the most critical AS in the region is the dominant ISP on the market, but not always.

As the number of alternate routes between ASes increases (the "Internet" stands for "interconnected networks" - and each network is an AS), so does the fault-tolerance and stability of the Internet across the globe. Although some paths are more important than others from the beginning, establishing as many alternate routes as possible is the only viable way to ensure an adequately robust network.

The global connectivity of any given AS, whether an international giant or a regional player, depends on the quantity and quality of its path to Tier-1 ISPs.

Usually, Tier-1 implies an international company offering global IP transit service over connections with other Tier-1 providers. Nevertheless, there is no guarantee that such connectivity will always be maintained. For many ISPs at all "tiers", losing connection to even one Tier-1 peer would likely render them unreachable from some parts of the world.

The first quarter of the year 2022 has passed; now, it is time to look at the events of Q1 in terms of mitigated DDoS activity and recorded BGP incidents.

It seems that the problem of calculating the absolute value of a number is completely trivial. If the number is negative, change the sign. Otherwise, just leave it as it is. In Java, it may look something like this:

public static double abs(double value) {
  if (value < 0) {
    return -value;
  }
  return value;
}

It seems to be too easy even for a junior interview question. Are there any pitfalls here?