Java Validator

There are two methods available for creating a Java-based validator in SwitchYard:

1. Implement the org.switchyard.validate.Validator interface and add a <validate.java> definition to your switchyard.xml.

2. Annotate one or more methods on your Java class with @Validator.

When using the @Validator annotation, the SwitchYard maven plugin will automatically generate the <validate.java> definition(s) for you and add them to the switchyard.xml packaged in your application.

@Named("MyValidatorBean")
public class MyValidator {
    @Validator(name = "{urn:switchyard-quickstart-demo:orders:1.0}submitOrder")
    public ValidationResult validate(Element from) {
       // handle validation here
    }
}

The above Java class would produce the <validate.java> definition as following:

<validate.java bean="MyValidatorBean"
               name="{urn:switchyard-quickstart-demo:orders:1.0}submitOrder"/>

The optional name element of the @Validator annotation can be used to specify the qualified type name used during validator registration.  If not supplied, the full class name of the method parameter will be used as the type.

The CDI bean name specified by @Named annotation is used to resolve validator class. If you don't specify, then class name of the validator is used instead like following:

<validates>
   <validate.java class="org.switchyard.quickstarts.demos.orders.MyValidator"
                   name="{urn:switchyard-quickstart-demo:orders:1.0}submitOrder"/>
</transforms>

Note that both of above <validate.java> definition has a bean attribute or a class attribute. bean attribute and class attribute are mutually exclusive.

ValidationResult

ValidationResult is a simple interface which represents the result of validation. It has 2 methods, isValid() and getDetail(). isValid() returns whether the validation succeeded or not. _getDetail() returns error message if validation failed.

package org.switchyard.validate;
public interface ValidationResult {
    boolean isValid();
    String getDetail();
}

There are 3 convenience methods on org.switchyard.validate.BaseValidator, validResult(), invalidResult(), and invalidResult(String) which help you to generate ValidationResult object.

Validation Failure

If validation fails, message exchange processing stops immediately, and HandlerException is thrown with the failure detail which is returned by ValidationResult.getDetail(). We recommend to return a ValidationResult with failure detail message when you want to indicate a validation failure in your Java Validator, instead of throwing a RuntimeException.

XML Validator

The XML validator allows you to perform a validation against its schema definition. Supported schema types are DTD, XML_SCHEMA, and RELAX_NG. It is configured simply by specifying the schema Type, the name QName, and the path to the schema file.

<validate.xml schemaType="XML_SCHEMA" name="{urn:switchyard-quickstart:validate-xml:0.1.0}order" failOnWarning="true" namespaceAware="true">
   <schemaFiles>
      <entry file="/xsd/orders.xsd"/>
   </schemaFiles>
   <schemaCatalogs>
      <entry file="/xsd/catalog.xml"/>
   </schemaCatalogs>
</validate.xml>

If you specify failOnWarning attribute as true, then validation would fail if any warning is detected during validation. If the XML content to be validated has namespace prefix, then you need to specify namespaceAware as true.

<schema xmlns="http://www.w3.org/2001/XMLSchema"
        targetNamespace="urn:switchyard-quickstart:validate-xml:0.1.0"
        xmlns:base="urn:switchyard-quickstart:validate-xml-base:0.1.0"
        xmlns:orders="urn:switchyard-quickstart:validate-xml:0.1.0">
        <import namespace="urn:switchyard-quickstart:validate-xml-base:0.1.0" schemaLocation="orders.base"/>
...

<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
    <system systemId="orders.base" uri="orders-base.xsd"/>
</catalog>