Posts Tagged ‘StateManagement’
[DotJs2024] Embracing Reactivity: Signals Unveiled in Modern Web Frameworks
As web architectures burgeon in intricacy, the quest for fluid state orchestration intensifies, demanding primitives that harmonize intuition with efficiency. Ruby Jane Cabagnot, a Oslo-based full-stack artisan and co-author of Practical Enterprise React, illuminated this quest at dotJS 2024. With a portfolio spanning cloud services and DevOps, Ruby dissected signals’ ascendancy in frameworks like SolidJS and Svelte, tracing their lineage from Knockout’s observables to today’s compile-time elixirs. Her exposition: a clarion for developers to harness these sentinels, streamlining reactivity while amplifying responsiveness.
Ruby’s odyssey commenced with historical moorings: Knockout’s MVVM pioneers observables, auto-propagating UI tweaks; AngularJS echoed with bidirectional bonds, model-view symphonies. React’s virtual DOM and hooks refined declarative flows, context cascades sans impurity. Yet, SolidJS and Svelte pioneer signals—granular beacons tracking dependencies, updating solely perturbed loci. In Solid, createSignal births a reactive vessel: name tweaks ripple to inputs, paragraphs—minimal footprint, maximal sync. Svelte compiles bindings at build: $: value directives weave reactivity into markup, runtime overhead evaporated.
Vue’s ref system aligns, signals as breath-easy bindings. Ruby extolled their triad: intuitiveness supplants boilerplate bazaars; performance prunes needless re-renders, DOM diffs distilled; developer delight via declarative purity, codebases crystalline. Signals transcend UIs, infiltrating WebAssembly’s server tides, birthing omnipresent reactivity. Ruby’s entreaty: probe these pillars, propel paradigms where apps pulse as dynamically as their environs.
Evolutionary Echoes of Reactivity
Ruby retraced trails: Knockout’s observables ignited auto-updates; AngularJS’s bonds synchronized realms. React’s hooks democratized context; Solid/Svelte’s signals granularize, compile-time cunning curbing cascades—name flux mends markup sans wholesale refresh.
Signals’ Synergies in Action
Solid’s vessels auto-notify dependents; Svelte’s directives distill runtime to essence. Vue’s refs render reactivity reflexive. Ruby rejoiced: libraries obsolete, renders refined, ergonomics elevated—crafting canvases concise, performant, profound.
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[DotJs2024] Adding Undo/Redo to Complex Web Apps
Enhancing user agency in labyrinthine applications hinges on forgiving interactions, where missteps dissolve with a keystroke. Bassel Ghandour, a senior software engineer at Contentsquare, distilled this essence into a brisk yet profound primer at dotJS 2024. From Paris’s vibrant tech scene—now his U.S. outpost—Ghandour lamented a botched virtual Tokyo greeting, swiftly invoking undo’s allure. His focus: retrofitting undo/redo into state-heavy web apps, sidestepping snapshot pitfalls for action-centric resilience.
Ghandour commenced with state management basics in a todo app: frontend mirrors app state, enter-press morphs it—additions, UI ripples. Naive undo? Timestamped snapshots, hopping between epochs. Reality intrudes: actions cascade side effects, backend ops interweave, concurrency clashes. Rapid todo barrages spawn interleaved sequences; snapshot reversion mid-thread invites chaos. Solution: encapsulate sequences under UUIDs, treating batches as atomic units. Parallel: forge inverses—add’s delete, toggle’s revert—mapping each to its antithesis.
This duality—do and undo in tandem—preserves fidelity. User crafts todo: UUID wraps creation, displays; inverse queues deletion. Subsequent show-toggle: nested UUID, inverse queued. Undo invokes the stack’s apex inverse, state reverts cleanly; redo replays forwards. Ghandour’s flow: capture actions, inverse-map, sequence-bundle, command-apply. Backend sync? Optimistic updates, rollbacks on failure. Contentsquare’s engineering blog details implementations, from Redux sagas to custom dispatchers.
Ghandour’s brevity belied depth: this pattern scales to e-commerce carts, design canvases, empowering serene navigation amid complexity. By prioritizing actions over states, developers liberate users, fostering trust in intricate digital environs.
Encapsulating Actions for Resilience
Ghandour advocated UUID-wrapped sequences, neutralizing concurrency: todo volleys become discrete do/undo pairs, applied reversibly. Inverse mapping—add-to-delete—ensures symmetry, backend integrations via optimistic commits. This sidesteps snapshot bloat, embracing flux with grace.
Implementing Undo/Redo Commands
Stacks manage history: push do with inverse, pop applies antithesis. Redo mirrors. Ghandour teased Contentsquare’s saga: Redux orchestration, UI hooks triggering cascades—scalable, testable, user-delighting.
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[KotlinConf2018] Taming State with Sealed Classes: Patrick Cousins’ Approach at Etsy
Lecturer
Patrick Cousins is a software engineer at Etsy with nearly 20 years of programming experience, passionate about new patterns and languages. He is known for his work on state management and seal-related puns. Relevant links: Etsy Code as Craft Blog (publications); LinkedIn Profile (professional page).
Abstract
This article examines Patrick Cousins’ use of Kotlin sealed classes to manage complex state in Etsy’s mobile apps. Contextualized in event-driven architectures, it explores methodologies for event streams with RxJava and when expressions. The analysis highlights innovations in exhaustiveness and type safety, contrasting Java’s limitations, with implications for robust state handling.
Introduction and Context
Patrick Cousins spoke at KotlinConf 2018 about sealed classes, inspired by his blog post on Etsy’s engineering site. Etsy’s mobile apps juggle complex state—listings, tags, shipping profiles—forming a “matrix of possibilities.” Sealed classes offer a type-safe way to model these, replacing Java’s error-prone instanceof checks and visitor patterns. This narrative unfolds where mobile apps demand reliable state management to avoid costly errors.
Methodological Approaches to State Management
Cousins modeled state as sealed class hierarchies, emitting events via RxJava streams. Using filterIsInstance and when, he ensured exhaustive handling of state types like Loading, Success, or Error. This avoided Java’s polymorphic indirection, where unrelated types forced artificial interfaces. Sealed classes, confined to one file, prevented unintended extensions, ensuring safety.
Analysis of Innovations and Features
Sealed classes innovate by guaranteeing exhaustiveness in when, unlike Java’s instanceof, which risks missing branches. Kotlin’s final-by-default classes eliminate Liskov substitution issues, avoiding polymorphic pitfalls. RxJava integration enables reactive updates, though requires careful ordering. Compared to Java, sealed classes simplify state logic without forced commonality, though complex hierarchies demand discipline.
Implications and Consequences
Cousins’ approach implies safer, more maintainable state management, critical for e-commerce apps. It reduces bugs from unhandled states, enhancing user experience. Consequences include a shift from polymorphic designs, though developers must adapt to sealed class constraints. The pattern encourages adoption in reactive systems.
Conclusion
Cousins’ use of sealed classes redefines state handling at Etsy, leveraging Kotlin’s type safety to create robust, readable mobile architectures.
Links
- Lecture video: https://www.youtube.com/watch?v=uGMm3StjqLI
- Lecturer’s X/Twitter: @patrickcousins
- Lecturer’s LinkedIn: Patrick Cousins
- Organization’s X/Twitter: @EtsyEng
- Organization’s LinkedIn: Etsy
[DevoxxFR2012] JavaServer Faces: Identifying Antipatterns and Embracing Best Practices for Robust Applications
Lecturer
Kito Mann leads as Principal Consultant at Virtua, Inc., focusing on enterprise architecture, training, and mentoring in JavaServer Faces (JSF), HTML5, portlets, Liferay, and Java EE. Editor-in-chief of JSFCentral.com, he co-hosts the Enterprise Java Newscast and hosts the JSF Podcast series. Author of “JavaServer Faces in Action” (Manning), Kito participates in JCP expert groups for CDI, JSF, and Portlets. An international speaker at events like JavaOne and JBoss World, he holds a BA in Computer Science from Johns Hopkins University.
Abstract
This article probes Kito Mann’s exploration of common pitfalls in JavaServer Faces (JSF) development, juxtaposed with recommended strategies for optimal performance and maintainability. It scrutinizes real-world antipatterns, from hardcoded IDs and database accesses in getters to broader issues like inconsistent standards and improper API usage. Embedded in JSF’s component-based framework, the analysis reviews techniques for dependency injection, state management, and view optimization. Via code illustrations and case studies, it evaluates consequences for scalability, team onboarding, and application longevity, advocating principled approaches to harness JSF’s strengths effectively.
Common Pitfalls in Component and Bean Management
JSF’s strength lies in its reusable components and managed beans, yet misuse breeds inefficiencies. Kito identifies hardcoding IDs in backing beans as a cardinal error—components autogenerate IDs, risking conflicts. Instead, employ bindings or relative references.
Database operations in getters exacerbate performance: invoked multiple times per request, they overload servers. Solution: Fetch data in lifecycle methods like init() or use lazy loading:
@PostConstruct
public void init() {
users = userService.getUsers();
}
Lack of standards fragments codebases; enforce conventions for naming, structure. Wrong APIs, like FacesContext in non-UI layers, violate separation—inject via CDI.
Optimizing State and View Handling
State management plagues JSF: View-scoped beans persist unnecessarily if not destroyed properly. Kito advises @ViewScoped with careful serialization.
Large views bloat state; mitigate with for partial renders or for modularization. c:if toggles subtrees but beware quirks—prefer rendered attributes unless tree pruning is essential.
Dependency lookups in getters repeat calls; leverage CDI injection:
@Inject
private UserProvider userProvider;
This ensures singletons are fetched once, enhancing efficiency.
Enhancing Performance Through Best Practices
Ajax integrations demand caution: Overuse swells requests. Optimize with execute/render attributes.
Navigation rules clutter; use implicit navigation or bookmarkable views with GET parameters.
Testing antipatterns include neglecting UI tests—employ JSFUnit or Selenium for comprehensive coverage.
Implications: These practices yield responsive, scalable apps. By avoiding antipatterns, teams reduce debugging, easing onboarding. In enterprise contexts, they align JSF with modern demands like mobile responsiveness.
Kito’s insights empower developers to refine JSF usage, maximizing framework benefits.