Tutorial by Examples: for

Motivation for the Memory Model

Consider the following example: public class Example { public int a, b, c, d; public void doIt() { a = b + 1; c = d + 1; } } If this class is used is a single-threaded application, then the observable behavior will be exactly as you would expect. For instan...

Java Language • Java Memory Model

FOR Loop

Loop FOR works on similar rules as other loops. FOR loop is executed exact number of times and this number is known at the beginning - lower and upper limits are directly set in code. In every step in this example, loop is increment by 1. Simple example: DECLARE v_counter NUMBER(2); --declaration...

plsql • Loop

Using an index for a date and time lookup

Many real-world database tables have many rows with DATETIME OR TIMESTAMP column values spanning a lot of time, including years or even decades. Often it's necessary to use a WHERE clause to retrieve some subset of that timespan. For example, we might want to retrieve rows for the date 1-September-2...

MySQL • Date and Time Operations

Apple's IFA vs. IFV (Apple Identifier for Advertisers vs. Identifier for Vendors)

You can use the IFA for measuring ad clicks and the IFV for measuring app installs. IFA has built-in privacy mechanisms that make it perfect for advertising. In contrast, the IFV is for developers to use internally to measure users who install their apps. IFA ASIdentifierManager class pr...

iOS • UUID (Universally Unique Identifier)

Angular 2 for-loop

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Angular 2 • Angular - ForLoop

DAX example formula

Previous Quarter Sales:=CALCULATE(FactSales[Sales], PREVIOUSQUARTER(DimDate[DateKey])) (Calculates the total sales for the previous quarter, based on the Sales column in the FactSales table and the DateKey in the DimDate table, depending on the filters applied in a PivotTable or PivotChart)

powerbi • Power Query (M) and DAX - What's the difference?

Happens-before relationships

(The following is a simplified version of what the Java Language Specification says. For a deeper understanding, you need to read the specification itself.) Happens-before relationships are the part of the Memory Model that allow us to understand and reason about memory visibility. As the JLS say...

Java Language • Java Memory Model

CloudFormation sample script to create an EC2 instance along with a Security Group to associate with.

This example will create an EC2 instance of t2.micro type in N.Virginia region running Amazon Linux. During the execution, it will ask to select the KeyPair to use and an I.P. CIDR from where you can SSH to the instance, use default to make SSH open to the internet { "AWSTemplateFormatVersion"...

amazon-web-services • AWS CloudFormation

Investigate Directories For Disk Usage

Sometimes it may be required to find out which directory consuming how much disk space especially when you are used df -h and realized your available disk space is low. du: du command summarizes disk usage of the set of FILEs, recursively for directories. It's often uses with -sh option: -s, --s...

GNU/Linux • Check Disk Space

FormCreation.java (iText 5)

In this iText 5 example, we'll create a text field and we'll add it to a PDF: public void manipulatePdf(String src, String dest) throws DocumentException, IOException { PdfReader reader = new PdfReader(src); PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest)); T...

itext • Forms: iText 5 vs iText 7

FormCreation.java (iText 7)

In this iText 7 example, we'll create a text field and we'll add it to a PDF: public void manipulatePdf(String src, String dest) throws IOException { PdfReader reader = new PdfReader(src); PdfDocument pdf = new PdfDocument(reader, new PdfWriter(dest)); PdfAcroForm form = PdfAcroFor...

itext • Forms: iText 5 vs iText 7

FormFilling.java (iText 5)

In this iText 5 example, we'll change the properties and the value of a text field: public void manipulatePdf(String src, String dest) throws DocumentException, IOException { PdfReader reader = new PdfReader(src); PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest)); ...

itext • Forms: iText 5 vs iText 7

FormFilling.java (iText 7)

In this iText 7 example, we'll change the properties and the value of a text field: public void manipulatePdf(String src, String dest) throws IOException { PdfReader reader = new PdfReader(src); PdfDocument pdf = new PdfDocument(reader, new PdfWriter(dest)); PdfAcroForm form = PdfA...

itext • Forms: iText 5 vs iText 7

Views for people

To show you how work the views, we will assume that we want to query the document of type people. To do so, we will first need a design document that will hold our views. Note: for the purpose of the example, we will use many views inside of 1 design document. Therefore, in a production environment...

couchdb • Views

Angular 2: Reactive Forms (a.k.a Model-driven Forms)

This example uses Angular 2.0.0 Final Release registration-form.component.ts import { FormGroup, FormControl, FormBuilder, Validators } from '@angular/forms'; @Component({ templateUrl: "./registration-form.html" }) export class ExampleComponent { ...

Angular 2 • Angular 2 Forms Update

Happens-before reasoning applied to some examples

We will present some examples to show how to apply happens-before reasoning to check that writes are visible to subsequent reads. Single-threaded code As you would expect, writes are always visible to subsequent reads in a single-threaded program. public class SingleThreadExample { public in...

Java Language • Java Memory Model

React installation for Rails using rails_react gem

Add react-rails to your Gemfile: gem 'react-rails' And install: bundle install Next, run the installation script: rails g react:install This will: create a components.js manifest file and a app/assets/javascripts/components/ directory, where you will put your components place the follo...

Ruby on Rails • React with Rails using react-rails gem

High Level Introduction to Information Security

It is a basic human instinct to assess risk and to accept or take some kind of action on that risk. This is the essence of security, which is the body of knowledge that provides a framework around this instinct. Security defines three key concepts in a triangular paradigm - Confidentiality, Integri...

security • Getting started with security

Setting Up Environment for Aurelia-cli Explained

OS: Mac OS X 10.11 (Should work on Windows / Linux since we are using Vagrant) Vagrant 1.8.4 Installed Directory Structure on Host OS (Mac OS): /path/to/project /provision /packages Note: If you use different vesions, be sure to update Variables at top of provision.sh script b...

aurelia • Aurelia CLI Explained

Configuration for fewer programming errors

There are very good configurations to force typings and get more helpful errors which are not activated by default. { "compilerOptions": { "alwaysStrict": true, // Parse in strict mode and emit "use strict" for each source file. // If you have wrong c...

TypeScript • tsconfig.json