/*
 * Hibernate Validator, declare and validate application constraints
 *
 * License: Apache License, Version 2.0
 * See the license.txt file in the root directory or <http://www.apache.org/licenses/LICENSE-2.0>.
 */
package org.hibernate.validator.constraints;

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

import org.hibernate.validator.constraints.ScriptAssert.List;


A class-level constraint, that evaluates a script expression against the
annotated element. This constraint can be used to implement validation
routines, that depend on multiple attributes of the annotated element.


Script expressions can be written in any scripting or expression language,
for which a JSR 223
("Scripting for the JavaTM Platform") compatible engine can be
found on the classpath. The following listing shows an example using the
JavaScript engine, which comes with the JDK:

@ScriptAssert(lang = "javascript", script = "_this.startDate.before(_this.endDate)")
public class CalendarEvent {
	private Date startDate;
	private Date endDate;
	//...
 }
 

Using a real expression language in conjunction with a shorter object alias
allows for very compact expressions:

@ScriptAssert(lang = "jexl", script = "_.startDate > _.endDate", alias = "_")
public class CalendarEvent {
	private Date startDate;
	private Date endDate;
	//...
 }
 

Accepts any type.

Author:
Gunnar Morling/**
 * <p>
 * A class-level constraint, that evaluates a script expression against the
 * annotated element. This constraint can be used to implement validation
 * routines, that depend on multiple attributes of the annotated element.
 * </p>
 * <p>
 * Script expressions can be written in any scripting or expression language,
 * for which a <a href="http://jcp.org/en/jsr/detail?id=223">JSR 223</a>
 * ("Scripting for the Java<sup>TM</sup> Platform") compatible engine can be
 * found on the classpath. The following listing shows an example using the
 * JavaScript engine, which comes with the JDK:
 * </p>
 * <pre>
 * {@code @ScriptAssert(lang = "javascript", script = "_this.startDate.before(_this.endDate)")
 * public class CalendarEvent {
 *
 * 	private Date startDate;
 *
 * 	private Date endDate;
 *
 * 	//...
 *
 * }
 * }
 * </pre>
 * <p>
 * Using a real expression language in conjunction with a shorter object alias
 * allows for very compact expressions:
 * </p>
 *
 * <pre>
 * {@code @ScriptAssert(lang = "jexl", script = "_.startDate > _.endDate", alias = "_")
 * public class CalendarEvent {
 *
 * 	private Date startDate;
 *
 * 	private Date endDate;
 *
 * 	//...
 *
 * }
 * }
 * </pre>
 * <p>
 * Accepts any type.
 * </p>
 *
 * @author Gunnar Morling
 */
@Documented
@Constraint(validatedBy = { })
@Target({ TYPE })
@Retention(RUNTIME)
@Repeatable(List.class)
public @interface ScriptAssert {

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

	Class<?>[] groups() default { };

	Class<? extends Payload>[] payload() default { };

	
Returns:
The name of the script language used by this constraint as expected by the JSR 223 ScriptEngineManager. A ConstraintDeclarationException will be thrown upon script evaluation, if no engine for the given language could be found./**
	 * @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();

	
Returns:
The script to be executed. The script must return Boolean.TRUE, if the annotated element could successfully be validated, otherwise Boolean.FALSE. Returning null or any type other than Boolean will cause a ConstraintDeclarationException upon validation. Any exception occurring during script evaluation will be wrapped into a ConstraintDeclarationException, too. Within the script, the validated object can be accessed from the 
        script context using the name specified in the alias attribute./**
	 * @return The script to be executed. The script must return
	 *         {@code Boolean.TRUE}, if the annotated element could
	 *         successfully be validated, otherwise {@code 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 object can be accessed from the {@link javax.script.ScriptContext
	 *         script context} using the name specified in the
	 *         {@code alias} attribute.
	 */
	String script();

	
Returns:
The name, under which the annotated element shall be registered
        within the script context. Defaults to "_this"./**
	 * @return The name, under which the annotated element shall be registered
	 *         within the script context. Defaults to "_this".
	 */
	String alias() default "_this";

	
Returns:
The name of the property for which you would like to report a validation error.
If given, the resulting constraint violation will be reported on the specified property.
If not given, the constraint violation will be reported on the annotated bean.
Since:
5.4/**
	 * @return The name of the property for which you would like to report a validation error.
	 * If given, the resulting constraint violation will be reported on the specified property.
	 * If not given, the constraint violation will be reported on the annotated bean.
	 *
	 * @since 5.4
	 */
	String reportOn() default "";

	
Defines several @ScriptAssert annotations on the same element. /**
	 * Defines several {@code @ScriptAssert} annotations on the same element.
	 */
	@Target({ TYPE })
	@Retention(RUNTIME)
	@Documented
	public @interface List {
		ScriptAssert[] value();
	}
}