almost.functional.utils

Class Preconditions

java.lang.Object

almost.functional.utils.Preconditions

public final class Preconditions
extends java.lang.Object

Utility operations designed to be used as precondition tests.

Method Summary

Methods

Modifier and Type	Method and Description
static java.lang.String	checkNonEmptyString(java.lang.String reference, java.lang.String errorMessage) Check that a String is not empty after removing whitespace.
static <T> T	checkNotNull(T reference, java.lang.String errorMessage) Check that a reference is not null, throwing a IllegalArgumentException if it is.
static java.lang.Class	isAssignableTo(java.lang.Class<?> reference, java.lang.Class<?> toValue, java.lang.String message) Check that one class is assignable to another.
static <T> T	precondition(T reference, Predicate<T> predicate, java.lang.Class<? extends java.lang.RuntimeException> ex, java.lang.String msg) Test a Predicate against a reference value, and if it fails throw a runtime exception with a message.

Methods inherited from class java.lang.Object

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

Method Detail

precondition

public static <T> T precondition(T reference,
                 Predicate<T> predicate,
                 java.lang.Class<? extends java.lang.RuntimeException> ex,
                 java.lang.String msg)
                      throws java.lang.RuntimeException

Test a Predicate against a reference value, and if it fails throw a runtime exception with a message.

Type Parameters:

T - The type of the reference value

Parameters:

reference - the value to test

predicate - the predicate test to invoke

ex - The RuntimeException to use

msg - The message to add to the exception

Returns:

The reference value

Throws:

java.lang.RuntimeException - An instance of ex if the predicate fails

checkNotNull

public static <T> T checkNotNull(T reference,
                 java.lang.String errorMessage)

Check that a reference is not null, throwing a IllegalArgumentException if it is.

Type Parameters:

T - the type of the reference

Parameters:

reference - The reference to check

errorMessage - the message for the exception if the reference is null

Throws:

java.lang.IllegalArgumentException - if the reference is null

checkNonEmptyString

public static java.lang.String checkNonEmptyString(java.lang.String reference,
                                   java.lang.String errorMessage)

Check that a String is not empty after removing whitespace.

Parameters:

reference - the string

errorMessage - the message for the exception

Throws:

java.lang.NullPointerException - if the String is null

java.lang.IllegalArgumentException - if the string is non-null but zero length

isAssignableTo

public static java.lang.Class isAssignableTo(java.lang.Class<?> reference,
                             java.lang.Class<?> toValue,
                             java.lang.String message)

Check that one class is assignable to another.

Parameters:

reference - the class to test

toValue - the class assigning to

message - the message used in the exception if thrown

Throws:

java.lang.ClassCastException - if the assignment can not be made