/*
* Copyright 2008 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.http.client;
/**
* Utility class for validating strings.
*
* TODO(mmendez): Is there a better place for this?
*/
final class StringValidator {
/**
* Returns true if the string is empty or null.
*
* @param string to test if null or empty
*
* @return true if the string is empty or null
*/
public static boolean isEmptyOrNullString(String string) {
return (string == null) || (0 == string.trim().length());
}
/**
* Throws if <code>value</code> is <code>null</code> or empty. This method
* ignores leading and trailing whitespace.
*
* @param name the name of the value, used in error messages
* @param value the string value that needs to be validated
*
* @throws IllegalArgumentException if the string is empty, or all whitespace
* @throws NullPointerException if the string is <code>null</code>
*/
public static void throwIfEmptyOrNull(String name, String value) {
assert (name != null);
assert (name.trim().length() != 0);
throwIfNull(name, value);
if (0 == value.trim().length()) {
throw new IllegalArgumentException(name + " cannot be empty");
}
}
/**
* Throws a {@link NullPointerException} if the value is <code>null</code>.
*
* @param name the name of the value, used in error messages
* @param value the value that needs to be validated
*
* @throws NullPointerException if the value is <code>null</code>
*/
public static void throwIfNull(String name, Object value) {
if (null == value) {
throw new NullPointerException(name + " cannot be null");
}
}
private StringValidator() {
}
}