com.io7m.jnull

Class NullCheck

java.lang.Object

com.io7m.jnull.NullCheck

public final class NullCheck
extends Object

Functions for enforcing non-nullable references at run time.

The functions are intended for use in the manner of assertions. That is, the program should behave identically if all of the checks are removed. The functions raise NullCheckException to indicate that a null reference has been explicitly forbidden (rather than the accidental deference implied by NullPointerException). Exceptions of this type are not intended to be caught and handled; they indicate program bugs.

See Also:

NullCheckException

Method Summary

Methods

Modifier and Type	Method and Description
static <T> T	notNull(T x) Check that x is not null, raising NullPointerException iff x == null.
static <T> T	notNull(T x, String message) Check that x is not null, raising NullPointerException iff x == null.
static <T,U extends Collection<T>> U	notNullAll(U x) Check that x is not null, and that all elements of x are not null, raising NullPointerException iff x == null.
static <T,U extends Collection<T>> U	notNullAll(U x, String message) Check that x is not null, and that all elements of x are not null, raising NullPointerException iff x == null.

Methods inherited from class java.lang.Object

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

Method Detail

notNull

@NonNull
public static <T> T notNull(@Nullable
                    T x)

Check that x is not null, raising NullPointerException iff x == null.

Type Parameters:

T - The type of values

Parameters:

x - An arbitrary value

Returns:

x

notNull

@NonNull
public static <T> T notNull(@Nullable
                    T x,
                    @NonNull
                    String message)

Check that x is not null, raising NullPointerException iff x == null.

Type Parameters:

T - The type of values

Parameters:

x - An arbitrary value

message - A descriptive message describing the value

Returns:

x

notNullAll

@NonNull
public static <T,U extends Collection<T>> U notNullAll(@Nullable
                                               U x)

Check that x is not null, and that all elements of x are not null, raising NullPointerException iff x == null.

Type Parameters:

T - The type of values

U - The type of collections of T

Parameters:

x - An arbitrary value

Returns:

x

notNullAll

@NonNull
public static <T,U extends Collection<T>> U notNullAll(@Nullable
                                               U x,
                                               @NonNull
                                               String message)

Check that x is not null, and that all elements of x are not null, raising NullPointerException iff x == null.

Type Parameters:

T - The type of values

U - The type of collections of T

Parameters:

x - An arbitrary value

message - A descriptive message describing the value

Returns:

x