| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.metrics2.util; |
| |
| /** |
| * Utilities for programming by contract (preconditions, postconditions etc.) |
| */ |
| public class Contracts { |
| |
| private Contracts() {} |
| |
| /** |
| * Check that a reference is not null. |
| * @param <T> type of the reference |
| * @param ref the reference to check |
| * @param msg the error message |
| * @throws NullPointerException if {@code ref} is null |
| * @return the checked reference for convenience |
| */ |
| public static <T> T checkNotNull(T ref, Object msg) { |
| if (ref == null) { |
| throw new NullPointerException(String.valueOf(msg) +": "+ |
| ref.getClass().getName()); |
| } |
| return ref; |
| } |
| |
| /** |
| * Check the state expression for false conditions |
| * @param expression the boolean expression to check |
| * @param msg the error message if {@code expression} is false |
| * @throws IllegalStateException if {@code expression} is false |
| */ |
| public static void checkState(boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalStateException(String.valueOf(msg)); |
| } |
| } |
| |
| /** |
| * Check an argument for false conditions |
| * @param <T> type of the argument |
| * @param arg the argument to check |
| * @param expression the boolean expression for the condition |
| * @param msg the error message if {@code expression} is false |
| * @return the argument for convenience |
| */ |
| public static <T> T checkArg(T arg, boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalArgumentException(String.valueOf(msg) +": "+ arg); |
| } |
| return arg; |
| } |
| |
| /** |
| * Check an argument for false conditions |
| * @param arg the argument to check |
| * @param expression the boolean expression for the condition |
| * @param msg the error message if {@code expression} is false |
| * @return the argument for convenience |
| */ |
| public static int checkArg(int arg, boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalArgumentException(String.valueOf(msg)+ ": "+arg); |
| } |
| return arg; |
| } |
| |
| /** |
| * Check an argument for false conditions |
| * @param arg the argument to check |
| * @param expression the boolean expression for the condition |
| * @param msg the error message if {@code expression} is false |
| * @return the argument for convenience |
| */ |
| public static long checkArg(long arg, boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalArgumentException(String.valueOf(msg)); |
| } |
| return arg; |
| } |
| |
| /** |
| * Check an argument for false conditions |
| * @param arg the argument to check |
| * @param expression the boolean expression for the condition |
| * @param msg the error message if {@code expression} is false |
| * @return the argument for convenience |
| */ |
| public static float checkArg(float arg, boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalArgumentException(String.valueOf(msg) +": "+ arg); |
| } |
| return arg; |
| } |
| |
| /** |
| * Check an argument for false conditions |
| * @param arg the argument to check |
| * @param expression the boolean expression for the condition |
| * @param msg the error message if {@code expression} is false |
| * @return the argument for convenience |
| */ |
| public static double checkArg(double arg, boolean expression, Object msg) { |
| if (!expression) { |
| throw new IllegalArgumentException(String.valueOf(msg) +": "+ arg); |
| } |
| return arg; |
| } |
| |
| } |