{"id":20580261,"url":"https://github.com/maif/functional-validation","last_synced_at":"2025-09-02T18:33:44.360Z","repository":{"id":38450009,"uuid":"298014192","full_name":"MAIF/functional-validation","owner":"MAIF","description":"A lib to validate data and stack errors 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Functional Validation  [![ga-badge][]][ga] [![jar-badge][]][jar]\n\n[ga]:               https://github.com/MAIF/functional-validation/actions?query=workflow%3ABuild\n[ga-badge]:         https://github.com/MAIF/functional-validation/workflows/Build/badge.svg\n[jar]:              https://maven-badges.herokuapp.com/maven-central/fr.maif/functional-validation\n[jar-badge]:        https://maven-badges.herokuapp.com/maven-central/fr.maif/functional-validation/badge.svg\n\n\nThis lib provide helpers to validate bean and compose validations stacking errors.  \n\n## Imports\n\nJcenter hosts this library.\n\n### Maven\n\n```xml\n\u003cdependency\u003e\n    \u003cgroupId\u003efr.maif\u003c/groupId\u003e\n    \u003cartifactId\u003efunctional-validation\u003c/artifactId\u003e\n    \u003cversion\u003e1.0.0-BETA1\u003c/version\u003e\n\u003c/dependency\u003e\n```\n\n### Gradle\n\n```\nimplementation 'fr.maif:functional-validation:1.0.0-BETA1'\n```\n\n## Combining validations  \n\n\n```java\npublic class Viking {\n\n    String name;\n    String email;\n    String website;\n    Integer age;\n\n    public Viking(String name, String email, String website, Integer age) {\n        this.name = name;\n        this.email = email;\n        this.website = website;\n        this.age = age;\n    }\n}\n\npublic class VikingValidation {\n\n    public static final String EMAIL_PATTERN = \"...\";\n    public static final String WEBSITE_URL_PATTERN = \"...\";\n\n    @SuppressWarnings(\"unchecked\")\n    public static \u003cE\u003e Rule\u003cE\u003e pattern(String elt, String pattern, E error) {\n        Pattern compiled = Pattern.compile(pattern);\n        if (compiled.matcher(elt).matches()) {\n            return Rule.valid();\n        } else {\n            return Rule.invalid(error);\n        }\n    }\n\n    public static Rule\u003cString\u003e validateWebsite(String elt) {\n        return pattern(elt, WEBSITE_URL_PATTERN, \"Website invalid\");\n    }\n\n    public static Rule\u003cString\u003e validateEmail(String elt) {\n        return pattern(elt, EMAIL_PATTERN, \"Email invalid\");\n    }\n\n    private static Rule\u003cString\u003e validateAge(Integer age) {\n        if (age \u003e 0 \u0026\u0026 age \u003c 130) {\n            return Rule.valid();\n        } else {\n            return Rule.invalid(\"Age should be between 0 and 130\");\n        }\n    }\n\n    public static \u003cE\u003e Rule\u003cString\u003e notNull(E elt) {\n        if (elt == null) {\n            return Rule.invalid(\"should not be null\");\n        } else {\n            return Rule.valid();\n        }\n    }\n\n    public static Rule\u003cString\u003e validateViking(Viking viking) {\n        return notNull(viking.email).andThen(() -\u003e validateEmail(viking.email))\n                .and(notNull(viking.website).andThen(() -\u003e validateWebsite(viking.website)))\n                .and(validateAge(viking.age));\n    }\n\n    // Or with combine instead of and \n    public static Rule\u003cString\u003e validateViking2(Viking viking) {\n        return Rule.combine(List.of(\n                    notNull(viking.email).andThen(() -\u003e validateEmail(viking.email)),\n                    notNull(viking.website).andThen(() -\u003e validateWebsite(viking.website)),\n                    validateAge(viking.age)\n        ));\n    }\n}\n\n```\n\nAnd then \n\n```java\nRule\u003cString\u003e validation = VikingValidation.validateViking(new Viking(\n        \"Ragnard\",\n        \"ragnar@gmail.com\",\n        \"https://ragnard.com\",\n        20\n));\n\nSystem.out.println(validation.isValid()); // true\nSystem.out.println(validation.isInvalid()); // false\nSystem.out.println(validation.getErrors()); // empty\nString foldOk = validation.fold(\n        errors -\u003e \"Validation failed with \" + errors.mkString(\", \"),\n        () -\u003e \"Validation succeed\"\n);\nSystem.out.println(foldOk);// \"Validation succeed\"\n\nRule\u003cString\u003e validationOnError = VikingValidation.validateViking(new Viking(\n        \"Ragnard\",\n        \"ragnar\",\n        \"ragnard\",\n        150\n));\n\nSystem.out.println(validationOnError.isValid()); // false\nSystem.out.println(validationOnError.isInvalid()); // true\nSystem.out.println(validationOnError.getErrors()); // [\"Email invalid\", \"Website invalid\", \"Age should be between 0 and 130\"]\nString foldKo = validationOnError.fold(\n        errors -\u003e \"Validation failed with \" + errors.mkString(\", \"),\n        () -\u003e \"Validation succeed\"\n); // \"Validation failed with Email invalid, Website invalid, Age should be between 0 and 130\"\n\nSystem.out.println(foldKo); // \"Validation failed with Email invalid, Website invalid, Age should be between 0 and 130\"\n```\n\n\n## Bean validation \n\nBean validation can be used and mix with rules \n\n```java\n\npublic class Viking {\n    @NotNull\n    public final String name;\n    @Email\n    public final String email;\n    @Pattern(regexp = WEBSITE_URL_PATTERN)\n    public final String website;\n    @Min(0)\n    @Max(130)\n    public final Integer age;\n\n    public Viking(String name, String email, String website, Integer age) {\n        this.name = name;\n        this.email = email;\n        this.website = website;\n        this.age = age;\n    }\n}\n\n```\n\nand then \n\n```java\n\nRule\u003cConstraintViolation\u003cViking\u003e\u003e validate = Rule.validate(new Viking(\n        \"Ragnard\",\n        \"ragnar\",\n        \"ragnard\",\n        150\n));\n\nRule\u003cString\u003e validationWithStringError = validate.mapError(ConstraintViolation::getMessage);\n\nRule\u003cString\u003e and = validationWithStringError.and(otherRule);\n```\n\n## Async validation \n\nSometime, validation is done using an external system where the call end with a future. \n\n```java\nString name = \"Ragnard\";\n\nViking viking = new Viking(\n        name,\n        \"ragnar\",\n        \"ragnard\",\n        150\n);\nRule\u003cConstraintViolation\u003cViking\u003e\u003e validate = Rule.validate(viking);\n\nRule\u003cString\u003e validationWithStringError = validate.mapError(ConstraintViolation::getMessage);\n\n// First validation and second only if the first is valid\nFuture\u003cRule\u003cString\u003e\u003e rules1 = validationWithStringError.andThenF(() -\u003e validateUserExists(viking.name));\n\n// Or with the two validations together\nFuture\u003cRule\u003cString\u003e\u003e rules2 = validationWithStringError.combineF(validateUserExists(name));\n\n// Or combining multiple rules (same as previous)\nFuture\u003cRule\u003cString\u003e\u003e rules3 = Rule.combineF(List(\n        Future(validationWithStringError),\n        validateUserExists(name)\n));\n\n```\n\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmaif%2Ffunctional-validation","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fmaif%2Ffunctional-validation","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmaif%2Ffunctional-validation/lists"}