1 /* 2 * Copyright (C) 2009 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect; 18 19 /** 20 * Thrown when a computer function returns null. This subclass exists so 21 * that our ReferenceCache adapter can differentiate null output from null 22 * keys, but we don't want to make this public otherwise. 23 * 24 * @author Bob Lee 25 */ 26 class NullOutputException extends NullPointerException { 27 public NullOutputException(String s) { 28 super(s); 29 } 30 private static final long serialVersionUID = 0; 31 } 32
