title: Request Parameters validations in vertx 4.0.3
body: <p>I was using <code>vertx-Web-api-contracts</code> in vertx 3.0 to validate my query parameters and form parameters using</p>
  <p><code>HTTPRequestValidationHandler</code> and <code>ParameterTypeValidator</code></p>
  <p>code sample :</p>
  <pre><code>private final ParameterTypeValidator fileIdValueValidator = new IdTypeValidator().create();
  private final ParameterTypeValidator tokenTypeValidator = new TokenTypeValidator().create();
  
  private HTTPRequestValidationHandler getDeleteRequestValidations() {
      final HTTPRequestValidationHandler validator = HTTPRequestValidationHandler.create()
          .addQueryParamWithCustomTypeValidator(PARAM__ID, IdValueValidator, true, false)
          .addHeaderParamWithCustomTypeValidator(HEADER_TOKEN, tokenTypeValidator, true, false);
      return validator;
  }
  </code></pre>
  <p>Here I am using ParameterTypeValidator to provide custom logic to validate my parameters value. I am using customTypeValidator, because I need custom value validation for parameter value
  for ex. I need to validate my ID Parameter should contain four parts separated by <strong>_</strong> ( <strong>part1_part2_part3_part4</strong> )</p>
  <p>Now while I am trying to migrate to <code>vertx 4.0</code> and <code>vertx-Web-api-contracts</code> is deprecated, I am forced to use <code>vertx-web-validation</code>, but web-validation lacks custompropertyvalidation like api-contract-validations.</p>
  <p>How I am trying to do,</p>
  <pre><code>private ValidationHandler getDeleteRequestValidations(final SchemaParser parser) {
      ValidationHandler validationHandler=ValidationHandler.builder(parser)
        .queryParameter(Parameters.param(PARAM__ID, stringSchema()))
        .headerParameter(Parameters.param(HEADER_TOKEN,stringSchema()))
        .build();
      return validationHandler;
    }
  </code></pre>
  <p>But I want to know how to pass/build a custom schema instead of <code>stringSchema()</code> or <code>intSchema()</code> to validate with custom logic. Earlier I was creating Custom classes and implements ParameterTypeValidator to provide custom validation logic(like <code>IdTypeValidator()</code>).</p>
  <p>Is there any way to achieve same with web-validation.</p>