FieldVerifier.java

/*
 * Copyright 2013, Cristiano Costantini, Giuseppe Gerla, Michele Ficarra, Sergio Ciampi, Stefano
 * Cigheri.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.developers.gdgfirenze.gwt.shared;

/**
 * <p>
 * FieldVerifier validates that the name the user enters is valid.
 * </p>
 * <p>
 * This class is in the <code>shared</code> package because we use it in both the client code and on
 * the server. On the client, we verify that the name is valid before sending an RPC request so the
 * user doesn't have to wait for a network round trip to get feedback. On the server, we verify that
 * the name is correct to ensure that the input is correct regardless of where the RPC originates.
 * </p>
 * <p>
 * When creating a class that is used on both the client and the server, be sure that all code is
 * translatable and does not use native JavaScript. Code that is not translatable (such as code that
 * interacts with a database or the file system) cannot be compiled into client side JavaScript.
 * Code that uses native JavaScript (such as Widgets) cannot be run on the server.
 * </p>
 */
public class FieldVerifier {

  /**
   * Verifies that the specified name is valid for our service.
   * 
   * In this example, we only require that the name is at least four characters. In your
   * application, you can use more complex checks to ensure that usernames, passwords, email
   * addresses, URLs, and other fields have the proper syntax.
   * 
   * @param name the name to validate
   * @return true if valid, false if invalid
   */
  public static boolean isValidName(String name) {
    if (name == null) {
      return false;
    }
    return name.length() > 3;
  }
}