de.unkrig.commons.lang

Class AssertionUtil

java.lang.Object

de.unkrig.commons.lang.AssertionUtil

public final class AssertionUtil
extends java.lang.Object

Various assertion-related utility methods.

Method Summary

Modifier and Type	Method and Description
static void	enableAssertionsFor(java.lang.Class<?> clasS) Enables assertions for the given clasS and the local and anonymous classes that it encloses, regardless of the "enable assertions" command line options that the JVM was started with.
static void	enableAssertionsForThisClass() Enables assertions for the class that invokes this method, regardless of the "enable assertions" command line options that the JVM was started with.
static java.lang.Object	fail() Identical with 'throw new AssertionError()', but returns an Object so it can be used in an expression.
static <T> T	fail(java.lang.String message) Identical with 'throw new AssertionError(message)', but returns an Object so it can be used in an expression.
static java.lang.Object	fail(java.lang.String message, java.lang.Throwable cause) Identical with 'throw new AssertionError(message, cause)', but returns an Object so it can be used in an expression.
static java.lang.Object	fail(java.lang.Throwable cause) Identical with 'throw new AssertionError(cause)', but returns an Object so it can be used in an expression.
static <T> T	notNull(T subject) Verifies that the subject is not null.
static <T> T	notNull(T subject, java.lang.String message) Verifies that the subject is not null.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

enableAssertionsFor

public static void enableAssertionsFor(java.lang.Class<?> clasS)

Enables assertions for the given clasS and the local and anonymous classes that it encloses, regardless of the "enable assertions" command line options that the JVM was started with.

Enabling assertions programmatically makes them much more useful, because unfortunately assertions are disabled by default and hardly any runtime environment provides a simple way to enable them.

Notice that the assertion status of a top-level type or member type is shared with the local and anonymous class that its methods declare, but not with the member types it declares. In other words: This method should be called for local classes and anonymous classes.

enableAssertionsForThisClass() is an even more elegant way to enable assertions for classes as they are loaded and initialized.

enableAssertionsForThisClass

public static void enableAssertionsForThisClass()

Enables assertions for the class that invokes this method, regardless of the "enable assertions" command line options that the JVM was started with.

     public class MyClass {

         static { AssertionUtil.enableAssertionsForThisClass(); }

         // ...
     }
 

Adding such static initializers to all classes makes assertions much more helpful, because unfortunately assertions are disabled by default and hardly any runtime environment provides a simple way to enable them.

Must only be called from the static initializer of a class.

Should not be called from local and anonymous classes, because these share the assertion state with the enclosing (non-local, non-anonymous) type.

notNull

public static <T> T notNull(@Nullable
                            T subject)

Verifies that the subject is not null.

Returns:

The subject

Throws:

java.lang.NullPointerException

notNull

public static <T> T notNull(@Nullable
                            T subject,
                            java.lang.String message)

Verifies that the subject is not null.

Returns:

The subject

Throws:

java.lang.NullPointerException - with the given message iff the subject is null

fail

public static java.lang.Object fail()

Identical with 'throw new AssertionError()', but returns an Object so it can be used in an expression.

fail

public static <T> T fail(java.lang.String message)

Identical with 'throw new AssertionError(message)', but returns an Object so it can be used in an expression.

fail

public static java.lang.Object fail(java.lang.Throwable cause)

Identical with 'throw new AssertionError(cause)', but returns an Object so it can be used in an expression.

fail

public static java.lang.Object fail(java.lang.String message,
                                    java.lang.Throwable cause)

Identical with 'throw new AssertionError(message, cause)', but returns an Object so it can be used in an expression.