org.forgerock.util

Class Reject

java.lang.Object

org.forgerock.util.Reject

public final class Reject
extends Object

A input parameter-validating utility class using fluent invocation:

 public int divide(int dividend, int divisor) {
     Reject.ifTrue(divisor == 0, "Division by zero not supported");
     return dividend / divisor;
 }
 

The example above will cause an IllegalArgumentException to be thrown with the message given.

Another use case is validating constructor parameters:

 public TokenManager(final TokenFactory factory) {
     Reject.ifNull(factory, "Cannot instantiate TokenManager with null TokenFactory");
 }
 

Sometimes, constructor parameters are passed to ancestor constructors which must be called first--thus, the checkNotNull syntax is available:

     import static org.forgerock.util.Reject.checkNotNull;

     public TokenManager(final TokenFactory factory) {
         super(checkNotNull(factory));
     }
 

Note that the methods herein throw generic RuntimeExceptions as opposed to custom, application-specific error Exceptions. This class is intended for wide use among multiple projects whose Exception frameworks may differ. The implementer is encouraged to catch the generic exceptions thrown by this class and rethrow exceptions appropriate to the target application.

Method Summary

Modifier and Type	Method and Description
static <T> T	checkNotNull(T object) Throws a NullPointerException if the object parameter is null, returns the object otherwise.
static <T> T	checkNotNull(T object, String message) Throws a NullPointerException if the object parameter is null, returns the object otherwise.
static void	ifFalse(boolean condition) Throws an IllegalArgumentException if the condition parameter is false.
static void	ifFalse(boolean condition, String message) Throws an IllegalArgumentException with a custom message if the condition parameter is false.
static void	ifNull(Object object) Alias for checkNotNull to be used in fluent Reject.ifNull syntax.
static void	ifNull(Object object, String message) Alias for checkNotNull to be used in fluent Reject.ifNull syntax.
static <T> void	ifNull(T... objects) Throws a NullPointerException if any of the provided arguments are null.
static void	ifTrue(boolean condition) Throws an IllegalArgumentException if the condition parameter is true.
static void	ifTrue(boolean condition, String message) Throws an IllegalArgumentException with a custom message if the condition parameter is true.
static void	rejectStateIfTrue(boolean condition, String message) Throws an IllegalStateException with a custom message if the condition parameter is true.

Methods inherited from class java.lang.Object

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

Method Detail

checkNotNull

public static <T> T checkNotNull(T object)

Throws a NullPointerException if the object parameter is null, returns the object otherwise.

Type Parameters:

T - The type of object to test.

Parameters:

object - the object to test

Returns:

the object

Throws:

NullPointerException - if object is null

checkNotNull

public static <T> T checkNotNull(T object,
                                 String message)

Throws a NullPointerException if the object parameter is null, returns the object otherwise.

Type Parameters:

T - The type of object to test.

Parameters:

object - the object to test

message - a custom exception message to use

Returns:

the object

Throws:

NullPointerException - if object is null

ifFalse

public static void ifFalse(boolean condition)

Throws an IllegalArgumentException if the condition parameter is false.

Parameters:

condition - the condition to test

Throws:

IllegalArgumentException - if condition is false

ifFalse

public static void ifFalse(boolean condition,
                           String message)

Throws an IllegalArgumentException with a custom message if the condition parameter is false.

Parameters:

condition - the condition to test

message - a custom exception message to use

Throws:

IllegalArgumentException - if condition is false

ifNull

public static void ifNull(Object object)

Alias for checkNotNull to be used in fluent Reject.ifNull syntax. Throws a NullPointerException if the object parameter is null.

Parameters:

object - the object to test

Throws:

NullPointerException - if object is null

ifNull

@SafeVarargs
public static <T> void ifNull(T... objects)

Throws a NullPointerException if any of the provided arguments are null.

Type Parameters:

T - The type of object to test.

Parameters:

objects - The objects to test.

Throws:

NullPointerException - If any of the provided arguments are null.

ifNull

public static void ifNull(Object object,
                          String message)

Alias for checkNotNull to be used in fluent Reject.ifNull syntax. Throws a NullPointerException if the object parameter is null.

Parameters:

object - the object to test

message - a custom exception message to use

Throws:

NullPointerException - if object is null

ifTrue

public static void ifTrue(boolean condition)

Throws an IllegalArgumentException if the condition parameter is true.

Parameters:

condition - the condition to test

Throws:

IllegalArgumentException - if condition is true

ifTrue

public static void ifTrue(boolean condition,
                          String message)

Throws an IllegalArgumentException with a custom message if the condition parameter is true.

Parameters:

condition - the condition to test

message - a custom exception message to use

Throws:

IllegalArgumentException - if condition is true

rejectStateIfTrue

public static void rejectStateIfTrue(boolean condition,
                                     String message)

Throws an IllegalStateException with a custom message if the condition parameter is true.

Parameters:

condition - the condition to test

message - a custom exception message to use

Throws:

IllegalStateException - if condition is true