2.4/samples/validation/src/com/google/gwt/sample/validation/server/GreetingServiceImpl.java

/*
 * Copyright 2010 Google Inc.
 *
 * 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.gwt.sample.validation.server;

import com.google.gwt.rpc.server.RpcServlet;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.sample.validation.client.GreetingService;
import com.google.gwt.sample.validation.shared.Person;
import com.google.gwt.sample.validation.shared.ServerGroup;

import java.util.HashSet;
import java.util.Set;

import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.groups.Default;

/**
 * The server side implementation of the RPC service.
 */
@SuppressWarnings("serial")
public class GreetingServiceImpl extends RpcServlet implements
    GreetingService {

  private final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();

  public SafeHtml greetServer(Person person) throws IllegalArgumentException,
      ConstraintViolationException {
    // Verify that the input is valid.
    Set<ConstraintViolation<Person>> violations = validator.validate(person,
        Default.class, ServerGroup.class);
    if (!violations.isEmpty()) {
      Set<ConstraintViolation<?>> temp = new HashSet<ConstraintViolation<?>>(
          violations);
      throw new ConstraintViolationException(temp);
    }

    String serverInfo = getServletContext().getServerInfo();
    String userAgent = getThreadLocalRequest().getHeader("User-Agent");

    // Escape data from the client to avoid cross-site script vulnerabilities.
    SafeHtmlBuilder builder = new SafeHtmlBuilder();

    SafeHtml safeHtml = builder//
    .appendEscapedLines("Hello, " + person.getName() + "!")//
    .appendHtmlConstant("<br>")//
    .appendEscaped("I am running " + serverInfo + ".")//
    .appendHtmlConstant("<br><br>")//
    .appendEscaped("It looks like you are using: ")//
    .appendEscaped(userAgent)//
    .toSafeHtml();
    return safeHtml;
  }
}