com.github.valid8j.classic

Enum Ensures

java.lang.Object

java.lang.Enum<Ensures>

com.github.valid8j.classic.Ensures

All Implemented Interfaces:

Serializable, Comparable<Ensures>

public enum Ensures
extends Enum<Ensures>

A class that offers entry-points for checking "postconditions" with a normal conditional statement of Java language. That is, if or ternary operator, not an assert statement. This means, the user of your product is not able to disable the checks you write at runtime, unlike ones written using assert statements.

The author of library thinks these methods should be used in "public facing" methods, when you should claim that the "external" party introduced the bug.

The author of library thinks these methods should be used in "public facing" context when the provider of the value to be examined introduced a bug, which makes the condition false.

For instance, it is an intended use-case, where you call ensure at the end of your method in order to express a condition to be satisfied by the value returned from your method.

Method Summary

Modifier and Type	Method and Description
static <T> T	ensure(T value, Predicate<? super T> cond) Checks if a given value satisfies a postcondition cond.
static <T> T	ensureNonNull(T value) Checks if a given value is not null.
static <T> T	ensureState(T value, Predicate<? super T> cond) Checks if a given state value`satisfies a postcondition `cond.
static Ensures	valueOf(String name) Returns the enum constant of this type with the specified name.
static Ensures[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

values

public static Ensures[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Ensures c : Ensures.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Ensures valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

ensureNonNull

public static <T> T ensureNonNull(T value)

Checks if a given value is not null. If not an exception will be thrown.

Type Parameters:

T - The type of the value.

Parameters:

value - A value to be checked.

Returns:

The value itself.

ensureState

public static <T> T ensureState(T value,
                                Predicate<? super T> cond)

Checks if a given state value`satisfies a postcondition `cond. If not an exception will be thrown.

Type Parameters:

T - The type of the value.

Parameters:

value - A value to be checked.

cond - A condition that checks value.

Returns:

The value itself

ensure

public static <T> T ensure(T value,
                           Predicate<? super T> cond)

Checks if a given value satisfies a postcondition cond. If not an exception will be thrown.

Type Parameters:

T - The type of the value.

Parameters:

value - A value to be checked.

cond - A condition that checks value.

Returns:

The value itself.