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/*
* Copyright 2002-2020 the original author or authors.
*
* 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
*
* https://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 nl.basjes.parse.useragent.utils.springframework.util;
import javax.annotation.Nullable;
/**
* Assertion utility class that assists in validating arguments.
*
* Useful for identifying programmer errors early and clearly at runtime.
*
*
For example, if the contract of a public method states it does not
* allow {@code null} arguments, {@code Assert} can be used to validate that
* contract. Doing this clearly indicates a contract violation when it
* occurs and protects the class's invariants.
*
*
Typically used to validate method arguments rather than configuration
* properties, to check for cases that are usually programmer errors rather
* than configuration errors. In contrast to configuration initialization
* code, there is usually no point in falling back to defaults in such methods.
*
*
This class is similar to JUnit's assertion library. If an argument value is
* deemed invalid, an {link IllegalArgumentException} is thrown (typically).
* For example:
*
*
* Assert.notNull(clazz, "The class must not be null");
* Assert.isTrue(i > 0, "The value must be greater than zero");
*
* Mainly for internal use within the framework; for a more comprehensive suite
* of assertion utilities consider {@code org.apache.commons.lang3.Validate} from
* Apache Commons Lang,
* Google Guava's
* Preconditions,
* or similar third-party libraries.
*
* @author Keith Donald
* @author Juergen Hoeller
* @author Sam Brannen
* @author Colin Sampaleanu
* @author Rob Harrop
* @since 1.1.2
*/
public abstract class Assert {
/**
* Assert a boolean expression, throwing an {@code IllegalStateException}
* if the expression evaluates to {@code false}.
*
Call {link #isTrue} if you wish to throw an {@code IllegalArgumentException}
* on an assertion failure.
*
Assert.state(id == null, "The id property must not already be initialized");
*
* @param expression a boolean expression
* @param message the exception message to use if the assertion fails
* @throws IllegalStateException if {@code expression} is {@code false}
*/
public static void state(boolean expression, String message) {
if (!expression) {
throw new IllegalStateException(message);
}
}
/**
* Assert a boolean expression, throwing an {@code IllegalArgumentException}
* if the expression evaluates to {@code false}.
* Assert.isTrue(i > 0, "The value must be greater than zero");
*
* @param expression a boolean expression
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if {@code expression} is {@code false}
*/
public static void isTrue(boolean expression, String message) {
if (!expression) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that an object is not {@code null}.
* Assert.notNull(clazz, "The class must not be null");
*
* @param object the object to check
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if the object is {@code null}
*/
public static void notNull(@Nullable Object object, String message) {
if (object == null) {
throw new IllegalArgumentException(message);
}
}
}