ImmutableClassChecker.java 文件源码

/**
 * Assert that the given class adheres to the immutable class rules, but
 * is not declared final.  Classes that need to be inherited from cannot be
 * declared final.
 *
 * @param clazz the class to check
 *
 * @throws java.lang.AssertionError if the class is not an
 *         immutable class
 */
public static void assertThatClassIsImmutableBaseClass(Class<?> clazz) {
    final ImmutableClassChecker checker = new ImmutableClassChecker();
    if (!checker.isImmutableClass(clazz, true)) {
        final Description toDescription = new StringDescription();
        final Description mismatchDescription = new StringDescription();

        checker.describeTo(toDescription);
        checker.describeMismatch(mismatchDescription);
        final String reason =
                "\n" +
                        "Expected: is \"" + toDescription.toString() + "\"\n" +
                        "    but : was \"" + mismatchDescription.toString() + "\"";

        throw new AssertionError(reason);
    }
}