Property names passed to
context.addError(message, "myProperty");
used to be limited to existing properties and could only be used if the constraint declaration was on the class-level.
Otherwise, an exception was raised.

I relaxed this rule as some people came with use cases involving validating property values by navigating properties hosted on the property value.

@SafeZipCodeAndCity
public Address getAddress() { ... }

Here is the new wording

Example 2.13. ConstraintValidatorContext interface passed to ConstraintValidator.isValid()

/**
 * Provide contextual data and operation when applying a given constraint validator implementation
 *
 * @author Emmanuel Bernard
 */
public interface ConstraintValidatorContext {
	/**
	 * Disable default error message and default ConstraintViolation object generation.
	 * Useful to set a different error message or generate an ConstraintViolation based on
	 * a different property
	 *
	 * @see #addError(String)
	 * @see #addError(String, String)
	 */
	void disableDefaultError();

	/**
	 * @return the current unexpanded default message
	 */
	String getDefaultErrorMessage();

	/**
	 * Add a new error message. This error message will be interpolated.
	 * <p/>
	 * If isValid returns false, a ConstraintViolation object will be built per error message
	 * including the default one unless #disableDefaultError() has been called.
	 * <p/>
	 * Aside from the error message, ConstraintViolation objects generated from such a call
	 * contains the same contextual information (root bean, path and so on)
	 * <p/>
	 * This method can be called multiple time. One ConstraintViolation instance per
	 * call is created.
	 *
	 * @param message new unexpanded error message
	 */
	void addError(String message);

	/**
	 * Add a new error message to a given sub property <code>property</code>.
	 * This error message will be interpolated.
	 * <p/>
	 * If isValid returns false, a ConstraintViolation object will be built
	 * per error message including the default one unless #disableDefaultError()
	 * has been called.
	 * <p/>
	 *
	 * @param message new unexpanded error message
	 * @param property property name the ConstraintViolation is targeting
	 */
	void addError(String message, String property);
}

The ConstraintValidatorContext interface allows to redefine the default message error generated when a constraint is not valid. By default, each invalid constraint leads to the generation of one error object represented by a ConstraintViolation object. This object is build from the default error message as defined by the constraint declaration and the context in which the constraint declaration is placed on (bean, property, attribute).

The ConstraintValidatorContext methods let the constraint implementation disable the default error object generation and create one or more custom ones. The unexpanded message passed as a parameter is used to build the ConstraintViolation object (the message interpolation operation is applied to it). The property on which the error object is applied is defined as following:

  • if property is not overridden, the current context the constraint is declared on is used (bean or property)

  • if the property is overridden, the current context the constraint is declared on the property passed as a parameter relative to the constraint declaration being evaluated

The property can be overridden by calling ConstraintValidatorContext.addError(String, String).