ComplexConstraintValidator.java

package org.gambi.tapestry5.cli.validators;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

import org.gambi.tapestry5.cli.annotations.ComplexValidationConstraint;
import org.gambi.tapestry5.cli.data.NestedBean;
import org.gambi.tapestry5.cli.services.internal.ApplicationConfigurationSource;

/**
 * This class is an example of implementation of a complex constraint specified
 * over a NestedBean. The constrain applies to objects of the type:
 * {@link NestedBean}.
 * 
 * In this example, the constraint check that the length of the beta property
 * inside the bean BeanA summed to the length of the first element of the
 * 'vector' property of the VectorBean is less than 20.
 * 
 * The take away message here is that we can define constraints on multiple
 * properties as long as they are nested in the (same) application configuration
 * object. In this case, an instance of the NestedBean must be contributed to
 * {@link ApplicationConfigurationSource} in order for the library to give its'
 * properties the values and to check for their validity
 * 
 * @author alessiogambi
 * 
 */
public class ComplexConstraintValidator implements
		ConstraintValidator<ComplexValidationConstraint, NestedBean> {

	public void initialize(ComplexValidationConstraint object) {
	}

	public boolean isValid(NestedBean bean,
			ConstraintValidatorContext paramConstraintValidatorContext) {
		if (bean == null) {
			System.out
					.println("ComplexConstraintValidator.isValid() bean == null) {");
			return true;
		} else if (bean.getBeanA() == null) {
			System.out
					.println("ComplexConstraintValidator.isValid() bean.getBeanA() == null) {");
			return true;
		} else if (bean.getVectorBean() == null) {
			System.out
					.println("ComplexConstraintValidator.isValid() (bean.getVectorBean() == null) {");
			return true;
		} else {
			try {
				System.out
						.println("ComplexConstraintValidator.isValid() TOT : "
								+ (bean.getBeanA().getBeta() + bean
										.getVectorBean().getVector()[0])
										.length());

				return (bean.getBeanA().getBeta() + bean.getVectorBean()
						.getVector()[0]).length() < 20;
			} catch (NullPointerException e) {
				System.out
						.println("ComplexConstraintValidator.isValid() NullPointerException");
				return true;
			} catch (Exception e) {
				e.printStackTrace();
				return false;
			}
		}
	}
}