AbstractUnicityValidator.java

package fr.openwide.core.wicket.more.util.validate.validators;

import javax.annotation.Nonnull;

import org.apache.wicket.Component;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.model.IModel;
import org.apache.wicket.validation.IValidatable;
import org.apache.wicket.validation.IValidator;
import org.apache.wicket.validation.ValidationError;

public abstract class AbstractUnicityValidator<T, V> extends Behavior implements IValidator<V> {
	
	private static final long serialVersionUID = -7514727402418569911L;
	
	public static final String MAIN_OBJECT_VARIABLE_NAME = "main";
	
	public static final String CONFLICTING_OBJECT_VARIABLE_NAME = "conflicting";

	private final IModel<? extends T> mainObjectModel;
	
	private final String errorKey;

	public AbstractUnicityValidator(IModel<? extends T> mainObjectModel, String errorKey) {
		super();
		this.mainObjectModel = mainObjectModel;
		this.errorKey = errorKey;
	}
	
	@Override
	public void detach(Component component) {
		super.detach(component);
		mainObjectModel.detach();
	}

	@Override
	public void validate(IValidatable<V> validatable) {
		T mainObject = mainObjectModel.getObject();
		T matchingObject = getByUniqueField(validatable.getValue());
		if (matchingObject != null && !isSame(matchingObject, mainObject)) {
			validatable.error(decorate(
					new ValidationError(this).addKey(errorKey)
							.setVariable(MAIN_OBJECT_VARIABLE_NAME, mainObject)
							.setVariable(CONFLICTING_OBJECT_VARIABLE_NAME, matchingObject)
			));
		}
	}
	
	protected boolean isSame(@Nonnull T matchingObject, T mainObject) {
		return matchingObject.equals(mainObject);
	}

	protected ValidationError decorate(ValidationError error) {
		// Does nothing by default
		return error;
	}

	protected abstract T getByUniqueField(V value);

}