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DDmitrid / datetime.java
Created February 6, 2019 13:36 — forked from salomvary/datetime.java
Java 8 Date and Time Parsing and Formatting Microtutorial
import java.time.format.DateTimeFormatter;
import java.time.Instant;
import java.time.ZonedDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
Instant.now();
// java.time.Instant = 2015-08-13T09:28:27.141Z
DateTimeFormatter.ISO_INSTANT.format(Instant.now());
@DDmitrid
DDmitrid / CamelCaseMacro.velocity
Last active January 22, 2019 14:43 — forked from Pencroff/CamelCaseMacro.velocity
Transformation file name to CamelCase in IntelliJ IDEA file templates
## file name transformation
## file-name => FileName
## Sources:
## http://stackoverflow.com/questions/6998412/velocity-string-function
## http://stackoverflow.com/questions/21288687/using-velocity-split-to-split-a-string-into-an-array-doesnt-seem-to-work
## http://velocity.apache.org/engine/releases/velocity-1.7/apidocs/org/apache/velocity/util/StringUtils.html#split(java.lang.String, java.lang.String)
#set( $CamelCaseName = "" )
#set( $part = "" )
@DDmitrid
DDmitrid / hikaricp-sqlserver-datasource
Created July 31, 2018 09:14 — forked from jampajeen/hikaricp-sqlserver-datasource
Create spring datasource for SQL Server & HikariCP
jdbc.driverClassName=com.microsoft.sqlserver.jdbc.SQLServerDriver
jdbc.url=jdbc:sqlserver://localhost:1433;databaseName=test
jdbc.username=myuser
jdbc.password=mypass
hikariCP.dataSourceClassName=com.microsoft.sqlserver.jdbc.SQLServerDataSource
@Bean
public DataSource dataSource(@Value("${hikariCP.dataSourceClassName}") String dataSourceClassName,
@Value("${jdbc.url}") String url,
@DDmitrid
DDmitrid / big-o-java-collections.md
Created July 27, 2018 11:34 — forked from FedericoPonzi/big-o-java-collections.md
Big O notation for java's collections

The book Java Generics and Collections has this information (pages: 188, 211, 222, 240).

List implementations:

                      get  add  contains next remove(0) iterator.remove
ArrayList             O(1) O(1) O(n)     O(1) O(n)      O(n)
LinkedList O(n) O(1) O(n) O(1) O(1) O(1)
@DDmitrid
DDmitrid / gist:9aaca12faa5d08255a8d297433cc2bce
Created July 27, 2018 11:31 — forked from psayre23/gist:c30a821239f4818b0709
Runtime Complexity of Java Collections
Below are the Big O performance of common functions of different Java Collections.
List | Add | Remove | Get | Contains | Next | Data Structure
---------------------|------|--------|------|----------|------|---------------
ArrayList | O(1) | O(n) | O(1) | O(n) | O(1) | Array
LinkedList | O(1) | O(1) | O(n) | O(n) | O(1) | Linked List
CopyOnWriteArrayList | O(n) | O(n) | O(1) | O(n) | O(1) | Array
@DDmitrid
DDmitrid / upgrade-postgres-9.6-to-10.md
Created July 16, 2018 08:56 — forked from mdesantis/upgrade-postgres-9.6-to-10.md
Upgrading PostgreSQL from 9.6 to 10 on Ubuntu 16.04

TL;DR

Install Postgres 10, and then:

sudo pg_dropcluster 10 main --stop
sudo pg_upgradecluster 9.6 main
sudo pg_dropcluster 9.6 main
@DDmitrid
DDmitrid / ffmpeg.md
Created May 7, 2018 09:21 — forked from protrolium/ffmpeg.md
using ffmpeg to extract audio from video files

ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

Convert WAV to MP3, mix down to mono (use 1 audio channel), set bit rate to 64 kbps and sample rate to 22050 Hz:

@DDmitrid
DDmitrid / Redis-BestPractices-General.md
Created March 9, 2018 11:56 — forked from JonCole/Redis-BestPractices-General.md
Redis Best Practices

Best Practices for Azure Redis

Below are a set of best practices that I recommend for most customers. This information is based on my experience helping hundreds of Azure Redis customers investigate various issues.

Configuration and Concepts

  1. Use Standard or Premium Tier for Production systems. The Basic Tier is a single node system with no data replication and no SLA. Also, use at least a C1 cache. C0 caches are really meant for simple dev/test scenarios since they have a shared CPU core, very little memory, are prone to "noisy neighbor", etc.
  2. Remember that Redis is an In-Memory data store. Read this article so that you are aware of scenarios where data loss can occur.
  3. Configure your client library to use a "connect timeout" of at least 10 to 15 seconds, giving the system time to connect even under higher CPU conditions. If your client or server tend to be under high load
@DDmitrid
DDmitrid / mongoDB.md
Created March 9, 2018 08:36 — forked from federico-garcia/mongoDB.md
MongoDB guide

Running mongodb

docker run -d -v $(pwd)/data/single:/data/db -v $(pwd)/config/single/mongod.conf:/etc/mongod.conf -p 27017:27017 --name mongo-server mongo:3.4 mongod -f /etc/mongod.conf

mongod - the server itself
mongo - mongodb cli (you can run js scripts)

default data directory: /data/db default DB: test default port: 27017 (config parameter net:port anf net:bindIp)

@DDmitrid
DDmitrid / redis.md
Created March 9, 2018 08:34 — forked from federico-garcia/redis.md
Redis

Redis

Redis stands for REmote DIctionary Server. By default, redis stores all data in memory. It's a key-structure database. redis-server is the actual datastore. redis-cli is the command line interface that performs any redis command. By default, redis binds to port 6379.

Starting the redis server

redis-server

While you can build a complete system using Redis only, I think most people will find that it supplements their more generic data solution - whether that be a traditional relational database, a document-oriented system, or something else. It’s the kind of solution you use to implement specific features.