Initial commit: v0.1.0 of levitas-validators

Author: GokulMV

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    name: Build & Test (Java ${{ matrix.java }})
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        java: [ '17', '21' ]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK ${{ matrix.java }}
+        uses: actions/setup-java@v4
+        with:
+          java-version: ${{ matrix.java }}
+          distribution: temurin
+          cache: maven
+
+      - name: Build and verify (includes tests + JaCoCo coverage check)
+        run: mvn -B verify
+
+      - name: Upload JaCoCo coverage report
+        if: matrix.java == '17'
+        uses: actions/upload-artifact@v4
+        with:
+          name: jacoco-report
+          path: target/site/jacoco/
+          retention-days: 14

.gitignore

@@ -0,0 +1,42 @@
+# Maven
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+.mvn/wrapper/maven-wrapper.jar
+
+# Compiled class files
+*.class
+
+# Log files
+*.log
+
+# IDE — IntelliJ IDEA
+.idea/
+*.iml
+*.iws
+*.ipr
+out/
+
+# IDE — Eclipse
+.classpath
+.project
+.settings/
+bin/
+
+# IDE — VS Code
+.vscode/
+*.code-workspace
+
+# OS
+.DS_Store
+Thumbs.db
+Desktop.ini
+
+# JaCoCo
+*.exec

CHANGELOG.md

@@ -0,0 +1,42 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.1.0] — 2024-04-13
+
+### Added
+
+- **GSTIN validator** (`GstinValidator`) — format validation, base-36 checksum verification,
+  state code extraction, PAN extraction, full parse into `GstinInfo`
+- **StateCode enum** — all 40 Indian state/UT GST codes with display names and
+  `fromCode(String)` lookup
+- **EntityType enum** — REGULAR entity type for GSTIN registration count character
+- **PAN validator** (`PanValidator`) — format validation, entity type extraction
+  (individual, company, HUF, firm, trust, government, AOP, BOI, local authority,
+  artificial juridical person)
+- **PanEntityType enum** — all 10 IT department entity type codes with descriptions
+- **HSN validator** (`HsnValidator`) — 2/4/6/8 digit validation, turnover-based
+  minimum digit requirements (4 digits ≤ ₹5 crore, 6 digits > ₹5 crore),
+  export/import 8-digit check
+- **IFSC validator** (`IfscValidator`) — format validation, bank code extraction,
+  bank name lookup, branch code extraction
+- **BankRegistry** — 46 major Indian banks bundled as JSON resource, loaded via Jackson
+- **UPI VPA validator** (`VpaValidator`) — format validation, username/handle extraction,
+  PSP name lookup
+- **PspRegistry** — 36 known UPI PSP handles bundled as JSON resource
+- **Aadhaar validator** (`AadhaarValidator`) — Verhoeff checksum validation, format check,
+  space/hyphen separator support
+- **AadhaarMasker** — DPDP-compliant masking (`XXXX-XXXX-NNNN` and compact formats)
+- **VerhoeffChecksum** (internal) — full Verhoeff algorithm implementation with
+  validate and computeChecksum methods
+- **BankAccountMasker** — full-mask and partial-mask helpers for bank account numbers
+- **Spring Boot demo** (`examples/spring-boot-demo/`) — REST API demo for all validators
+- **GitHub Actions CI** — builds and tests on Java 17 and 21, uploads JaCoCo coverage
+
+[Unreleased]: https://github.com/levitasOrg/levitas-validators/compare/v0.1.0...HEAD
+[0.1.0]: https://github.com/levitasOrg/levitas-validators/releases/tag/v0.1.0

CONTRIBUTING.md

@@ -0,0 +1,60 @@
+# Contributing to Levitas Validators
+
+Thank you for considering a contribution! This document covers how to build the project, add a new validator, our code style, and the PR checklist.
+
+## Building
+
+```bash
+# Full build with tests and coverage check (requires Java 17+, Maven 3.9+)
+mvn verify
+
+# Skip tests for a quick compile check
+mvn verify -DskipTests
+
+# Run only tests
+mvn test
+```
+
+The JaCoCo coverage check is enforced at 85% line coverage. New code should aim for 90%+.
+
+## Adding a new validator
+
+1. Create a new package under `src/main/java/io/github/levitasorg/validators/` (e.g., `tan/`).
+2. Implement the validator class as a final utility class (private constructor, static methods).
+3. Add Javadoc on every public method. At minimum: what it validates, what it returns, and null-safety contract.
+4. Add a corresponding test class under `src/test/java/...` mirroring the main package.
+5. Add tests for: null input, empty input, wrong length, invalid format, valid examples, and edge cases.
+6. If your validator needs bundled data (e.g., a lookup table), add a JSON resource under `src/main/resources/levitas/` and load it via Jackson in a registry class.
+7. Run `mvn verify` — all tests must pass and coverage must stay above 85%.
+
+## Code style
+
+- Java 17, no Lombok
+- Immutable where possible; no mutable static state after initialization
+- All public classes and methods must have Javadoc
+- Static factory methods preferred over constructors for utility-like output types
+- No hardcoded real Aadhaar, PAN, GSTIN, or other PII in tests — use generated or obviously-fake test data
+- No network calls anywhere in the library
+- All validators must be null-safe: `isValid(null)` returns `false`, `parse(null)` throws `IllegalArgumentException` with a clear message, `extractX(null)` returns `Optional.empty()`
+
+## Test requirements
+
+- 90%+ line coverage for new code
+- Each new public method needs at least one positive and one negative test
+- Null-safety tests for all public methods
+- Thread-safety tested for validators that will be called in concurrent contexts
+
+## PR checklist
+
+Before opening a pull request, verify:
+
+- [ ] `mvn verify` passes locally (tests + coverage)
+- [ ] All new public methods have Javadoc
+- [ ] No real PII in test data
+- [ ] No network calls introduced
+- [ ] Code follows existing style (immutability, null safety, static utility pattern)
+- [ ] CHANGELOG.md updated with the change under `[Unreleased]`
+
+## Issue tracker
+
+Issues and feature requests: [GitHub Issues](https://github.com/levitasOrg/levitas-validators/issues)

LICENSE

@@ -0,0 +1,179 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship made available under
+      the License, as indicated by a copyright notice that is included in
+      or attached to the work (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other transformations
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean, as submitted to the Licensor for inclusion
+      in the Work by the copyright owner or by an individual or Legal Entity
+      authorized to submit on behalf of the copyright owner. For the purposes
+      of this definition, "submitted" means any form of electronic, verbal,
+      or written communication sent to the Licensor or its representatives,
+      including but not limited to communication on electronic mailing lists,
+      source code control systems, and issue tracking systems that are managed
+      by, or on behalf of, the Licensor for the purpose of discussing and
+      improving the Work, but excluding communication that is conspicuously
+      marked or designated in writing by the copyright owner as "Not a
+      Contribution."
+
+      "Contributor" shall mean Licensor and any Legal Entity on behalf of
+      whom a Contribution has been received by the Licensor and included
+      within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by the combined Contribution(s) with the
+      Work to which such Contribution(s) was submitted. If You institute
+      patent litigation against any entity (including a cross-claim or
+      counterclaim in a lawsuit) alleging that the Work or any Contribution
+      embodied within the Work constitutes patent or contributory patent
+      infringement, then any patent licenses granted to You under this
+      License for that Work shall terminate as of the date such litigation
+      is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or Derivative
+          Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, You must include a readable copy of the
+          attribution notices contained within such NOTICE file, in
+          at least one of the following places: within a NOTICE text
+          file distributed as part of the Derivative Works; within
+          the Source form or documentation, if provided along with the
+          Derivative Works; or, within a display generated by the
+          Derivative Works, if and wherever such third-party notices
+          normally appear. The contents of the NOTICE file are for
+          informational purposes only and do not modify the License.
+          You may add Your own attribution notices within Derivative
+          Works that You distribute, alongside or in addition to the
+          NOTICE text from the Work, provided that such additional
+          attribution notices cannot be construed as modifying the License.
+
+      You may add Your own license statement for Your modifications and
+      may provide additional grant of rights to use, copy, modify, merge,
+      publish, distribute, sublicense, and/or sell copies of Your
+      modifications, or for such Derivative Works as a whole, under the
+      terms of this License, if You otherwise comply with the conditions
+      in Sections 4(a), 4(b), and 4(c) of this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or reproducing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or exemplary damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (even if such Contributor has been advised of the possibility
+      of such damages).
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may offer only
+      conditions consistent with this License.
+
+   END OF TERMS AND CONDITIONS
+
+   Copyright 2024 Levitas Org
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.