Note: Functional Interfaces in Java

 (source: Java SE 8 for the Really Impatient: Programming with Lambdas - 3.3. Choosing a Functional Interface)

Common Functional Interfaces

Functional Interface	Parameter Types	Return Type	Abstract Method Name	Description	Other Methods
Runnable	none	void	run	Runs an action without arguments or return value
Supplier<T>	none	T	get	Supplies a value of type T
Consumer<T>	T	void	accept	Consumes a value of type T	chain
BiConsumer<T, U>	T, U	void	accept	Consumes values of types T and U	chain
Function<T, R>	T	R	apply	A function with argument of type T	compose, andThen, identity
BiFunction<T, U, R>	T, U	R	apply	A function with arguments of types T and U	andThen
UnaryOperator<T>	T	T	apply	A unary operator on the type T	compose, andThen, identity
BinaryOperator<T>	T, T	T	apply	A binary operator on the type T	andThen
Predicate<T>	T	boolean	test	A Boolean-valued function	and, or, negate, isEqual
BiPredicate<T, U>	T, U	boolean	test	A Boolean-valued function with two arguments	and, or, negate

Functional Interfaces for Primitive Types

p, q is int, long, double; P, Q is Int, Long, Double

Functional Interface	Parameter Types	Return Type	Abstract Method Name
BooleanSupplier	none	boolean	getAsBoolean
PSupplier	none	p	getAsP
PConsumer	p	void	accept
ObjPConsumer<T>	T, p	void	accept
PFunction<T>	p	T	apply
PToQFunction	p	q	applyAsQ
ToPFunction<T>	T	p	applyAsP
ToPBiFunction<T, U>	T, U	p	applyAsP
PUnaryOperator	p	p	applyAsP
PBinaryOperator	p, p	p	applyAsP
PPredicate	p	boolean	test

CSS: frequently used selectors

Basic selectors 

Wildcard selector: selects all elements

* {}

Type selector: selects all elements of the given type

div {}

Attribute selector ([]): selects all elements that has the given attribute

[src] {}

ID selector (#): selects the element with the given ID attribute

#menu {} /* or [id="menu"] {} */

Class selector (.): selects all elements with the given class attribute

.centered {} /* or [class~="centered"] {} */

Selector grouping

selector grouping (,): enables to specify common values in one place

div, #menu, .centered {}

Selector chaining

Selector chaining

div.#menu.centered[name="Menu"]:first-child::first-letter {}

Attribute value selectors

[attribute="value"] selector: selects all elements with the specified attribute and value

[target="_blank"] {}

[attribute~="value"] selector: selects all elements whose attribute value contains the specified whole word.

[title~="flower"] {}

[attribute|="value"] selector: selects all elements whose attribute value starts with the specified value, the value being a whole word or the first part of a hyphenated word.

[class|="top"] {}

[attribute^="value"] selector: selects all elements whose attribute value begins with the specified value. (like in regex)

[class^="top"] {}

[attribute$="value"] selector: selects all elements whose attribute value ends with the specified value. (like in regex)

[class$="test"] {}

[attribute*="value"] selector: selects all elements whose attribute value contains the specified value.

[class*="te"] {}

Selector combination

Descendant selector (space): matches all elements that are descendants of a specified element

div p {}

Child selector (>): selects all elements that are the immediate children of a specified element

div > p {}

Adjacent sibling selector (+): selects all elements that are the adjacent siblings of a specified element

div + p {}

General sibling selector (~): selects all elements that are siblings of a specified element

div ~ p {}

GIT: useful commands

Checkout and start tracking remote branch:

git checkout --track origin/branchname

Publish and create tracking connection for new local branch:

git push -u <remote> <branch>

Revert changes made to your working copy:

git checkout .

Revert changes made to the index: (i.e., that you have added). Warning this will reset all of your unpushed commits to master!

git reset

Revert a change that you have committed:

git revert <commit 1> <commit 2>

Remove untracked files (e.g., new files, generated files):

git clean -f

Remove untracked directories (e.g., new or automatically generated directories):

git clean -fd

Remove ignored files (e.g., IDE configuration):

git clean -fX

Remove ignored directories (e.g., IDE configuration, target dir)
git clean -fdX

Rebase develop branch to master. (Develop will be checked out):

git rebase master develop

Delete branch with all its commits:

git branch -D <branch-name>

Create patch file of staged changes (ignore whitespace differences, like line endings):

git diff --cached --ignore-space-change >> patch.diff

Clean up list of remote branches

git remote prune <origin>

sources:

• https://stackoverflow.com/questions/1146973/how-do-i-revert-all-local-changes-in-git-managed-project-to-previous-state
• https://stackoverflow.com/questions/7726949/remove-tracking-branches-no-longer-on-remote
• https://git-scm.com/docs/git-diff
• https://git-scm.com/docs/git-rebase

Mercurial Hg - frequently used commands

hg clone

copy a locally non-existent repository from remote repository

hg pull --rebase

pull changes from remote to local, rebase local commits on new head

hg pull -u

pull changes from remote to local, update working dir to new head

hg update [optionally: where]

updates working dir to head or specified revision

hg st
hg status

list status of the working directory

hg commit

commit changes

hg commit --amend

amend last commit

hg push

push to remote repository

hg rebase -s [what] -d [where]

rebase one commit and its children to another commit -- commits specified by [commit number]

hg strip --keep [what and its children]

remove a commit and its children, and keep the changes in the working directory

hg strip [what and its children]

delete a commit and its children (will not keep changes!)

hg purge

cleans the working directory

hg shelve
hg unshelve

shelve or unshelve changes in the working directory

Docker: frequently used commands

list all images:

docker images

list all containers:

docker ps -a

stop all running containers:

docker stop $(docker ps -a -q)

remove all containers:

docker rm $(docker ps -a -q)

force (-f) remove all running or non-running containers:

docker rm -f $(docker ps -a -q)

remove all images:

docker rmi $(docker images -q)

build docker image with the tag tutorial/webapp:latest from the path .:

docker build -t tutorial/webapp:latest .

download a docker image from the docker hub:

docker pull tutorial/webapp:latest

run the image tutorial/webapp with the specified --name, in the background (-d), exposing inner port 8080 on 80 (-p) and setting an environmental variable (-e):

docker run --name tutorial -d -p 80:8080 -e "ENV_VAR=env-var" tutorial/webapp

run bash console inside the container:

docker exec -it nameofthecontainer /bin/bash

build a docker image from a Dockerfile in the current directory:

docker build --tag my_image .