Validator.java

/*******************************************************************************
 * This file is part of OpenNMS(R).
 *
 * Copyright (C) 2011 The OpenNMS Group, Inc.
 * OpenNMS(R) is Copyright (C) 1999-2011 The OpenNMS Group, Inc.
 *
 * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
 *
 * OpenNMS(R) is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 *
 * OpenNMS(R) is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with OpenNMS(R).  If not, see:
 *      http://www.gnu.org/licenses/
 *
 * For more information contact:
 *     OpenNMS(R) Licensing <license@opennms.org>
 *     http://www.opennms.org/
 *     http://www.opennms.com/
 *******************************************************************************/


package org.opennms.gwt.web.ui.asset.client.tools.validation;

import org.opennms.gwt.web.ui.asset.client.tools.fieldsets.AbstractFieldSet;

/**
 * @author <a href="mailto:MarkusNeumannMarkus@gmail.com">Markus Neumann</a>
 * 
 *         Validators are simple classes to check if a given parameter is valid
 *         following an defined rule. Validators are used in
 *         {@link AbstractFieldSet} instances to check if input is valid.
 *         Validators results are string based. So "" = it's valid. Any returned
 *         string != "" is an validation fail. Just add validators that fits to
 *         given object-type!
 */
public interface Validator {
	/**
	 * Validates the given object by a implemented rule.
	 * 
	 * @param object
	 *            to validate.
	 * @return "" means it is valid. "Message" means not valid, with the
	 *         returned reason.
	 */
	public String validate(Object object);
}