de.rwth.swc.coffee4j.engine.util

Class Preconditions

java.lang.Object

de.rwth.swc.coffee4j.engine.util.Preconditions

public final class Preconditions
extends Object

Preconditions which can be used to validate the argument passed to methods. This functionality is already implemented with guava, but importing the complete guava library for just the preconditions seems like a bit of an overkill.

Method Summary

Modifier and Type	Method and Description
static void	check(boolean expression) Checks whether the given expression evaluates to true.
static void	check(boolean expression, String message) Checks whether the given expression evaluates to true.
static void	check(boolean expression, java.util.function.Supplier<String> messageSupplier) Checks whether the given expression evaluates to true.
static <T> Collection<T>	doesNotContainNull(Collection<T> collection) Checks if the given Collection contains any null element.
static <T> Collection<T>	doesNotContainNull(Collection<T> collection, String message) Checks if the given Collection contains any null element.
static <T> Collection<T>	doesNotContainNull(Collection<T> collection, java.util.function.Supplier<String> messageSupplier) Checks if the given Collection contains any null element.
static <T> T	notNull(T object) Checks if the given object is null.
static <T> T	notNull(T object, String message) Checks if the given object if null.
static <T> T	notNull(T object, java.util.function.Supplier<String> messageSupplier) Checks if the given object is null.

Methods inherited from class java.lang.Object

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

Method Detail

notNull

public static <T> T notNull(T object)

Checks if the given object is null. If this is the case, a NullPointerException is thrown.

Type Parameters:

T - the type of the object. This is needed to return the correct type again

Parameters:

object - the object to be checked

Returns:

the object which was passed if it is not null

Throws:

NullPointerException - if the passed object is null

notNull

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

Checks if the given object if null. If this is the case, a NullPointerException with the given message is thrown.

Type Parameters:

T - the type of the object. This is needed to returned the correct type again

Parameters:

object - the object to be checked

message - the message for the exception if the object is null

Returns:

the object which was passed if it is not null

Throws:

NullPointerException - if the passed object is null

notNull

public static <T> T notNull(T object,
                            java.util.function.Supplier<String> messageSupplier)

Checks if the given object is null. If this is the case, a NullPointerException with the message provided by the Supplier is thrown.

Type Parameters:

T - the type of the object. This is needed to returned the correct * type again

Parameters:

object - the object to be checked

messageSupplier - a supplier for the message of the exception which will be thrown if object is null

Returns:

the object which was passed if it is not null

Throws:

NullPointerException - if the passed object is null

doesNotContainNull

public static <T> Collection<T> doesNotContainNull(Collection<T> collection)

Checks if the given Collection contains any null element. If this is the case, a IllegalArgumentException is thrown.

Type Parameters:

T - the type of the collection

Parameters:

collection - to be examined for a null element. Must not be null

Returns:

the same collection which was initally given to this method

Throws:

IllegalArgumentException - if collection contains null

NullPointerException - if the collection it was null itself. Note that some Collection implementations may throw a NullPointerException during the check if they do not permit the null type

doesNotContainNull

public static <T> Collection<T> doesNotContainNull(Collection<T> collection,
                                                   String message)

Checks if the given Collection contains any null element. If this is the case, a IllegalArgumentException with the given message is thrown.

Type Parameters:

T - the type of the collection

Parameters:

collection - to be examined for a null element. Must not be null

message - for the exception if it is thrown

Returns:

the same collection which was initally given to this method

Throws:

IllegalArgumentException - if collection contains null

NullPointerException - if the collection it was null itself. Note that some Collection implementations may throw a NullPointerException during the check if they do not permit the null type

doesNotContainNull

public static <T> Collection<T> doesNotContainNull(Collection<T> collection,
                                                   java.util.function.Supplier<String> messageSupplier)

Checks if the given Collection contains any null element. If this is the case, a IllegalArgumentException with the message given by the supplier.

Type Parameters:

T - the type of the collection

Parameters:

collection - to be examined for a null element. Must not be null

messageSupplier - for the exception message if it is thrown

Returns:

the same collection which was initally given to this method

Throws:

IllegalArgumentException - if collection contains null

NullPointerException - if the collection it was null itself. Note that some Collection implementations may throw a NullPointerException during the check if they do not permit the null type

check

public static void check(boolean expression)

Checks whether the given expression evaluates to true. If this is not the case, an IllegalArgumentException is thrown.

Parameters:

expression - the expression to be evaluated

Throws:

IllegalArgumentException - if the expression evaluates to false

check

public static void check(boolean expression,
                         String message)

Checks whether the given expression evaluates to true. If this is not the case, an IllegalArgumentException with the given message is thrown.

Parameters:

expression - the expression to be evaluated

message - the message for the exception

Throws:

IllegalArgumentException - if the expression evaluates to false

check

public static void check(boolean expression,
                         java.util.function.Supplier<String> messageSupplier)

Checks whether the given expression evaluates to true. If this is not the case, an IllegalArgumentException with the message given by the Supplier is thrown.

Parameters:

expression - the expression to be evaluated

messageSupplier - the supplier for the exception message

Throws:

IllegalArgumentException - if the expression evaluates to false