Tutorial by Examples: en

Here we have a class and we want the identity field (userUid) to have its value generated via a SEQUENCE in the database. This SEQUENCE is assumed to be called USER_UID_SEQ, and can be created by a DBA, or can be created by the JPA provider. @Entity @Table(name="USER") public class User...

If you want to remove calls to certain methods, assuming they return void and have no side affects (as in, calling them doesn't change any system values, reference arguments, statics, etc.) then you can have ProGuard remove them from the output after the build is complete. For example, I find this ...

For functions that need to take a collection of objects, slices are usually a good choice: fn work_on_bytes(slice: &[u8]) {} Because Vec<T> and arrays [T; N] implement Deref<Target=[T]>, they can be easily coerced to a slice: let vec = Vec::new(); work_on_bytes(&vec); le...

The column text may change upon the horizontal resizing of a column. There are three methods to accomplish this: Method NameMaximum Length of Headingset_short_text10set_medium_text20set_long_text40 The following example shows usage of all three. A column object is declared and instantiated as a re...

The following method call enables usage of many advanced features such as sorting, filtering, and exporting data. alv->get_functions( )->set_all( ).

This method increases readability by giving consecutive rows alternating background color shading. alv->get_display_settings( )->set_striped_pattern( if_salv_c_bool_sap=>true ).

@Singleton @Component(modules = AppModule.class) public interface AppComponent { void inject(App app); Context provideContext(); Gson provideGson(); MainActivityComponent mainActivityComponent(ActivityModule activityModule); } @ActivityScope @Subcomponent(modules = Act...

Values passed as enum constructor arguments can be captured into variables by use of pattern matching. Assume the following enum: enum Color { RGB(r : Int, g : Int, b : Int); HSV(h : Int, s : Float, v : Float); } The red channel value can be captured as follows: var color = Color.RG...

Enum constructors can be matched using pattern matching. Assume the following enum: enum Color { Red; Green; Blue; RGB(r : Int, g : Int, b : Int); } Colours with only a green channel value can be matched as follows: var color = Color.RGB(0, 127, 0); var isGreenOnly = swit...

Overview These instructions are for acquiring, building, and installing openssl from source. Openssl is usually included in package managers as well. Resources https://github.com/openssl/openssl Dependencies make perl 5 gcc/clang git Dependencies can be installed through a package mana...

Problem: Vim users are not always happy. Solution: Make them happy. 7.4 :smile Note: Requires patch version ≥7.4.1005

The simplest way to get an event handler called on a key press is to connect the handler to the key-press-event signal. In this example, we register for the event for the whole window, but you can also register for individual widgets too. The most important part is the connection of the handler to ...

textBox.SelectionStart = textBox.TextLength; textBox.ScrollToCaret(); Applying the same principle, SelectionStart can be set to 0 to scroll to the top or to a specific number to go to a specific character.

A StringBuilder represents a series of characters, which unlike a normal string, are mutable. Often times there is a need to modify strings that we've already made, but the standard string object is not mutable. This means that each time a string is modified, a new string object needs to be created,...

If you are using Leiningen and your tests are located in the test directory in your project root then you can run your tests using lein test

The most common way is to apply the extension via Config. Example: # File: mysite/_config/config.yml Member: extensions: - MyMemberExtension The extensions config variable is of type "array", so you can add multiple extensions like this: # File: mysite/_config/config.yml Mem...

Some procedures have optional arguments. Optional arguments always come after required arguments, but the procedure can be called without them. For example, if the function, ProcedureName were to have two required arguments (argument1, argument2), and one optional argument, optArgument3, it could b...

RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_URI} !(.*)/$ RewriteRule ^(.*)$ /$1/ [L,R=301] The first RewriteCond helps exclude the files. The second RewriteCond checks if there is already a trailing slash. If the case is so RewriteRule is not applied. If you have any URL that s...

Laravel's events allows to implement the Observer pattern. This can be used to send a welcome email to a user whenever they register on your application. New events and listeners can be generated using the artisan command line utility after registering the event and their particular listener in App...

Though the transaction class method is called on some ActiveRecord class, the objects within the transaction block need not all be instances of that class. This is because transactions are per-database connection, not per-model. In this example a balance record is transactionally saved even though ...