website·Indexed 29 days ago
https://studying.sshine.ltdA collection of technical study notes covering Groovy syntax and object orientation, Kubernetes (K8s) components, objects, and Pod scheduling, Java concurrency and thread pools, and Vue 3 migration from Vue 2.
AQS is a framework for implementing synchronizers that control access to shared resources based on a state. It provides the underlying infrastructure for behaviors such as:
Groovy Truth is a mechanism that generalizes the concept of true to 'truthy'. When a value is used in a boolean context (like an if statement or assert), Groovy evaluates it based on the following rules:
true is true, false is false. A Boolean object that is null is evaluated as false.[:]) are false.'') are false.hasNext() to determine truthiness.null is false.Matcher object is considered true if the find() method returns true.// Collections
def arr = [] as String[]; assert !arr
def list = [1]; assert list
// Maps
assert ![:]
assert [one: null]
// Strings
assert '0'
assert !''
// Numbers
assert !0
assert 1
// Objects
assert new Object()
assert !nullUsing a thread pool instead of manually creating new threads (via new Thread()) provides three primary advantages:
Kubernetes (K8s) is a portable, extensible open-source platform for managing containerized workloads and services, enabling declarative configuration and automation. It provides the following key operational capabilities:
A Pod is the smallest deployable computing unit in Kubernetes that can be created and managed. It represents a group of one or more containers that are colocated, scheduled together, and share a common context.
Key characteristics include:
Addons use Kubernetes resources (like DaemonSets and Deployments) to provide cluster-level features. These are typically located in the kube-system namespace.
Common Addons include:
Vue 3 introduces several core improvements over Vue 2:
getter/setter approach (used for legacy browser support) with Proxy-based interception for responsive objects, while retaining getter/setter specifically for ref.setup function transforms declarative logic into compositional logic, improving type declarations and development standardization.kubeadm can be used.Almost every Kubernetes object contains two nested fields used to manage configuration: spec and status.
spec (Specification): Describes the desired state of the object (e.g., how many replicas should be running).status (Status): Describes the current actual state of the object.Kubernetes continuously works to move the current state (status) toward the desired state (spec). For example, if a Deployment specifies 3 replicas but one fails, Kubernetes will restart a pod to restore the desired state.
/**@ and ending with */ can be preserved after compilation. This allows accessing documentation content at runtime via the .groovydoc.content property on classes, methods, and fields. This feature requires the JVM argument -Dgroovy.attach.runtime.groovydoc=true to be active./**@
* User class
*/
class User {
/**@
* Username
*/
String username
}
// Accessing the runtime doc
println User.class.groovydoc.content
println User.class.getDeclaredField("username").groovydoc.contentas operator is used for type casting and conversion. Internally, it calls the asType() method. You can implement custom conversion logic for your own classes by overriding the asType(Class clazz) method.// Basic usage
Integer i = "42" as Integer
Integer[] is = [] as Integer[]
// Custom conversion
class MP3 {
String filename
Object asType(Class clazz) {
if (clazz == WAV) {
def wav = new WAV()
wav.filename = filename
return wav
}
throw new ClassCastException("MP3 cannot be converted to $clazz")
}
}
class WAV { String filename }
def mp3 = new MP3(filename: "song.mp3")
def wav = mp3 as WAV