/*
* Copyright 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 Atlassian Pty Ltd
*
* 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 org.bson.assertions;
/**
* <p>Design by contract assertions.</p> <p>This class is not part of the public API and may be removed or changed at any time.</p>
*/
public final class Assertions {
/**
* Throw IllegalArgumentException if the value is null.
*
* @param name the parameter name
* @param value the value that should not be null
* @param <T> the value type
* @return the value
* @throws IllegalArgumentException if value is null
*/
public static <T> T notNull(final String name, final T value) {
if (value == null) {
throw new IllegalArgumentException(name + " can not be null");
}
return value;
}
/**
* Throw IllegalStateException if the condition if false.
*
* @param name the name of the state that is being checked
* @param condition the condition about the parameter to check
* @throws IllegalStateException if the condition is false
*/
public static void isTrue(final String name, final boolean condition) {
if (!condition) {
throw new IllegalStateException("state should be: " + name);
}
}
/**
* Throw IllegalArgumentException if the condition if false.
*
* @param name the name of the state that is being checked
* @param condition the condition about the parameter to check
* @throws IllegalArgumentException if the condition is false
*/
public static void isTrueArgument(final String name, final boolean condition) {
if (!condition) {
throw new IllegalArgumentException("state should be: " + name);
}
}
/**
* Cast an object to the given class and return it, or throw IllegalArgumentException if it's not assignable to that class.
*
* @param clazz the class to cast to
* @param value the value to cast
* @param errorMessage the error message to include in the exception
* @param <T> the Class type
* @return value cast to clazz
* @throws IllegalArgumentException if value is not assignable to clazz
*/
@SuppressWarnings("unchecked")
public static <T> T convertToType(final Class<T> clazz, final Object value, final String errorMessage) {
if (!clazz.isAssignableFrom(value.getClass())) {
throw new IllegalArgumentException(errorMessage);
}
return (T) value;
}
private Assertions() {
}
}