org.hibernate.validator.constraints.ParameterScriptAssert Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of hibernate-validator

Following the DRY (Don't Repeat Yourself) principle, Hibernate Validator let's you express your domain constraints once (and only once) and ensure their compliance at various level of your system automatically.

There is a newer version: 9.0.0.Beta3

Show newest version

/*
 * Hibernate Validator, declare and validate application constraints
 *
 * License: Apache License, Version 2.0
 * See the license.txt file in the root directory or .
 */
package org.hibernate.validator.constraints;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * 
 * A method-level constraint, that evaluates a script expression against the
 * annotated method or constructor. This constraint can be used to implement
 * validation routines that depend on several parameters of the annotated
 * executable.
 * 
 * 
 * Script expressions can be written in any scripting or expression language,
 * for which a JSR 223
 * ("Scripting for the Java^TM Platform") compatible engine can be
 * found on the classpath. To refer to a parameter within the scripting
 * expression, use its name as obtained by the active
 * {@link javax.validation.ParameterNameProvider}. By default, {@code arg0}, {@code arg1} etc.
 * will be used as parameter names.
 * 
 * 
 * The following listing shows an example using the JavaScript engine which
 * comes with the JDK:
 * 
 *  * {@code @ParameterScriptAssert(script = "arg0.before(arg1)", lang = "javascript")
 * public void createEvent(Date start, Date end) { ... }
 * }
 * 
 * 
 * Can be specified on any method or constructor.
 * 
 *
 * @author Gunnar Morling
 */
@Target({ CONSTRUCTOR, METHOD })
@Retention(RUNTIME)
@Constraint(validatedBy = { })
@Documented
public @interface ParameterScriptAssert {

	String message() default "{org.hibernate.validator.constraints.ParametersScriptAssert.message}";

	Class[] groups() default { };

	Class[] payload() default { };

	/**
	 * @return The name of the script language used by this constraint as
	 *         expected by the JSR 223 {@link javax.script.ScriptEngineManager}. A
	 *         {@link javax.validation.ConstraintDeclarationException} will be thrown upon script
	 *         evaluation, if no engine for the given language could be found.
	 */
	String lang();

	/**
	 * @return The script to be executed. The script must return
	 *         Boolean.TRUE, if the executable parameters could
	 *         successfully be validated, otherwise Boolean.FALSE.
	 *         Returning null or any type other than Boolean will cause a
	 *         {@link javax.validation.ConstraintDeclarationException} upon validation. Any
	 *         exception occurring during script evaluation will be wrapped into
	 *         a ConstraintDeclarationException, too. Within the script, the
	 *         validated parameters can be accessed using their names as retrieved from the
	 *         active {@link javax.validation.ParameterNameProvider}.
	 */
	String script();

	/**
	 * Defines several {@link ParameterScriptAssert} annotations on the same executable.
	 */
	@Target({ CONSTRUCTOR, METHOD })
	@Retention(RUNTIME)
	@Documented
	public @interface List {
		ParameterScriptAssert[] value();
	}
}