io.jsonwebtoken.lang.Assert Maven / Gradle / Ivy
/*
* Copyright (C) 2014 jsonwebtoken.io
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.jsonwebtoken.lang;
import java.util.Collection;
import java.util.Map;
/**
* Utility methods for providing argument and state assertions to reduce repeating these patterns and otherwise
* increasing cyclomatic complexity.
*/
public final class Assert {
private Assert() {
} //prevent instantiation
/**
* Assert a boolean expression, throwing IllegalArgumentException
* if the test result is false.
* Assert.isTrue(i > 0, "The value must be greater than zero");
*
* @param expression a boolean expression
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if expression is false
*/
public static void isTrue(boolean expression, String message) {
if (!expression) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert a boolean expression, throwing IllegalArgumentException
* if the test result is false.
* Assert.isTrue(i > 0);
*
* @param expression a boolean expression
* @throws IllegalArgumentException if expression is false
*/
public static void isTrue(boolean expression) {
isTrue(expression, "[Assertion failed] - this expression must be true");
}
/**
* Assert that an object is null .
* Assert.isNull(value, "The value must be null");
*
* @param object the object to check
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if the object is not null
*/
public static void isNull(Object object, String message) {
if (object != null) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that an object is null .
* Assert.isNull(value);
*
* @param object the object to check
* @throws IllegalArgumentException if the object is not null
*/
public static void isNull(Object object) {
isNull(object, "[Assertion failed] - the object argument must be null");
}
/**
* Assert that an object is not null .
* Assert.notNull(clazz, "The class must not be null");
*
* @param object the object to check
* @param the type of object
* @param message the exception message to use if the assertion fails
* @return the non-null object
* @throws IllegalArgumentException if the object is null
*/
public static T notNull(T object, String message) {
if (object == null) {
throw new IllegalArgumentException(message);
}
return object;
}
/**
* Assert that an object is not null .
* Assert.notNull(clazz);
*
* @param object the object to check
* @throws IllegalArgumentException if the object is null
*/
public static void notNull(Object object) {
notNull(object, "[Assertion failed] - this argument is required; it must not be null");
}
/**
* Assert that the given String is not empty; that is,
* it must not be null and not the empty String.
* Assert.hasLength(name, "Name must not be empty");
*
* @param text the String to check
* @param message the exception message to use if the assertion fails
* @see Strings#hasLength
*/
public static void hasLength(String text, String message) {
if (!Strings.hasLength(text)) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given String is not empty; that is,
* it must not be null and not the empty String.
* Assert.hasLength(name);
*
* @param text the String to check
* @see Strings#hasLength
*/
public static void hasLength(String text) {
hasLength(text,
"[Assertion failed] - this String argument must have length; it must not be null or empty");
}
/**
* Assert that the given String has valid text content; that is, it must not
* be null and must contain at least one non-whitespace character.
* Assert.hasText(name, "'name' must not be empty");
*
* @param the type of CharSequence
* @param text the CharSequence to check
* @param message the exception message to use if the assertion fails
* @return the CharSequence if it has text
* @see Strings#hasText
*/
public static T hasText(T text, String message) {
if (!Strings.hasText(text)) {
throw new IllegalArgumentException(message);
}
return text;
}
/**
* Assert that the given String has valid text content; that is, it must not
* be null and must contain at least one non-whitespace character.
* Assert.hasText(name, "'name' must not be empty");
*
* @param text the String to check
* @see Strings#hasText
*/
public static void hasText(String text) {
hasText(text,
"[Assertion failed] - this String argument must have text; it must not be null, empty, or blank");
}
/**
* Assert that the given text does not contain the given substring.
* Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
*
* @param textToSearch the text to search
* @param substring the substring to find within the text
* @param message the exception message to use if the assertion fails
*/
public static void doesNotContain(String textToSearch, String substring, String message) {
if (Strings.hasLength(textToSearch) && Strings.hasLength(substring) &&
textToSearch.indexOf(substring) != -1) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given text does not contain the given substring.
* Assert.doesNotContain(name, "rod");
*
* @param textToSearch the text to search
* @param substring the substring to find within the text
*/
public static void doesNotContain(String textToSearch, String substring) {
doesNotContain(textToSearch, substring,
"[Assertion failed] - this String argument must not contain the substring [" + substring + "]");
}
/**
* Assert that an array has elements; that is, it must not be
* null and must have at least one element.
* Assert.notEmpty(array, "The array must have elements");
*
* @param array the array to check
* @param message the exception message to use if the assertion fails
* @return the non-empty array for immediate use
* @throws IllegalArgumentException if the object array is null or has no elements
*/
public static Object[] notEmpty(Object[] array, String message) {
if (Objects.isEmpty(array)) {
throw new IllegalArgumentException(message);
}
return array;
}
/**
* Assert that an array has elements; that is, it must not be
* null and must have at least one element.
* Assert.notEmpty(array);
*
* @param array the array to check
* @throws IllegalArgumentException if the object array is null or has no elements
*/
public static void notEmpty(Object[] array) {
notEmpty(array, "[Assertion failed] - this array must not be empty: it must contain at least 1 element");
}
/**
* Assert that the specified byte array is not null and has at least one byte element.
*
* @param array the byte array to check
* @param msg the exception message to use if the assertion fails
* @return the byte array if the assertion passes
* @throws IllegalArgumentException if the byte array is null or empty
* @since 0.12.0
*/
public static byte[] notEmpty(byte[] array, String msg) {
if (Objects.isEmpty(array)) {
throw new IllegalArgumentException(msg);
}
return array;
}
/**
* Assert that the specified character array is not null and has at least one byte element.
*
* @param chars the character array to check
* @param msg the exception message to use if the assertion fails
* @return the character array if the assertion passes
* @throws IllegalArgumentException if the character array is null or empty
* @since 0.12.0
*/
public static char[] notEmpty(char[] chars, String msg) {
if (Objects.isEmpty(chars)) {
throw new IllegalArgumentException(msg);
}
return chars;
}
/**
* Assert that an array has no null elements.
* Note: Does not complain if the array is empty!
* Assert.noNullElements(array, "The array must have non-null elements");
*
* @param array the array to check
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if the object array contains a null element
*/
public static void noNullElements(Object[] array, String message) {
if (array != null) {
for (int i = 0; i < array.length; i++) {
if (array[i] == null) {
throw new IllegalArgumentException(message);
}
}
}
}
/**
* Assert that an array has no null elements.
* Note: Does not complain if the array is empty!
* Assert.noNullElements(array);
*
* @param array the array to check
* @throws IllegalArgumentException if the object array contains a null element
*/
public static void noNullElements(Object[] array) {
noNullElements(array, "[Assertion failed] - this array must not contain any null elements");
}
/**
* Assert that a collection has elements; that is, it must not be
* null and must have at least one element.
* Assert.notEmpty(collection, "Collection must have elements");
*
* @param collection the collection to check
* @param the type of collection
* @param message the exception message to use if the assertion fails
* @return the non-null, non-empty collection
* @throws IllegalArgumentException if the collection is null or has no elements
*/
public static > T notEmpty(T collection, String message) {
if (Collections.isEmpty(collection)) {
throw new IllegalArgumentException(message);
}
return collection;
}
/**
* Assert that a collection has elements; that is, it must not be
* null and must have at least one element.
* Assert.notEmpty(collection, "Collection must have elements");
*
* @param collection the collection to check
* @throws IllegalArgumentException if the collection is null or has no elements
*/
public static void notEmpty(Collection collection) {
notEmpty(collection,
"[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
}
/**
* Assert that a Map has entries; that is, it must not be null
* and must have at least one entry.
* Assert.notEmpty(map, "Map must have entries");
*
* @param map the map to check
* @param the type of Map to check
* @param message the exception message to use if the assertion fails
* @return the non-null, non-empty map
* @throws IllegalArgumentException if the map is null or has no entries
*/
public static > T notEmpty(T map, String message) {
if (Collections.isEmpty(map)) {
throw new IllegalArgumentException(message);
}
return map;
}
/**
* Assert that a Map has entries; that is, it must not be null
* and must have at least one entry.
* Assert.notEmpty(map);
*
* @param map the map to check
* @throws IllegalArgumentException if the map is null or has no entries
*/
public static void notEmpty(Map map) {
notEmpty(map, "[Assertion failed] - this map must not be empty; it must contain at least one entry");
}
/**
* Assert that the provided object is an instance of the provided class.
* Assert.instanceOf(Foo.class, foo);
*
* @param the type of instance expected
* @param clazz the required class
* @param obj the object to check
* @return the expected instance of type {@code T}
* @throws IllegalArgumentException if the object is not an instance of clazz
* @see Class#isInstance
*/
public static T isInstanceOf(Class clazz, Object obj) {
return isInstanceOf(clazz, obj, "");
}
/**
* Assert that the provided object is an instance of the provided class.
* Assert.instanceOf(Foo.class, foo);
*
* @param type the type to check against
* @param the object's expected type
* @param obj the object to check
* @param message a message which will be prepended to the message produced by
* the function itself, and which may be used to provide context. It should
* normally end in a ": " or ". " so that the function generate message looks
* ok when prepended to it.
* @return the non-null object IFF it is an instance of the specified {@code type}.
* @throws IllegalArgumentException if the object is not an instance of clazz
* @see Class#isInstance
*/
public static T isInstanceOf(Class type, Object obj, String message) {
notNull(type, "Type to check against must not be null");
if (!type.isInstance(obj)) {
throw new IllegalArgumentException(message +
"Object of class [" + (obj != null ? obj.getClass().getName() : "null") +
"] must be an instance of " + type);
}
return type.cast(obj);
}
/**
* Asserts that the provided object is an instance of the provided class, throwing an
* {@link IllegalStateException} otherwise.
* Assert.stateIsInstance(Foo.class, foo);
*
* @param type the type to check against
* @param the object's expected type
* @param obj the object to check
* @param message a message which will be prepended to the message produced by
* the function itself, and which may be used to provide context. It should
* normally end in a ": " or ". " so that the function generate message looks
* ok when prepended to it.
* @return the non-null object IFF it is an instance of the specified {@code type}.
* @throws IllegalStateException if the object is not an instance of clazz
* @see Class#isInstance
*/
public static T stateIsInstance(Class type, Object obj, String message) {
notNull(type, "Type to check cannot be null.");
if (!type.isInstance(obj)) {
String msg = message + "Object of class [" + Objects.nullSafeClassName(obj) +
"] must be an instance of " + type;
throw new IllegalStateException(msg);
}
return type.cast(obj);
}
/**
* Assert that superType.isAssignableFrom(subType) is true.
* Assert.isAssignable(Number.class, myClass);
*
* @param superType the super type to check
* @param subType the sub type to check
* @throws IllegalArgumentException if the classes are not assignable
*/
public static void isAssignable(Class superType, Class subType) {
isAssignable(superType, subType, "");
}
/**
* Assert that superType.isAssignableFrom(subType) is true.
* Assert.isAssignable(Number.class, myClass);
*
* @param superType the super type to check against
* @param subType the sub type to check
* @param message a message which will be prepended to the message produced by
* the function itself, and which may be used to provide context. It should
* normally end in a ": " or ". " so that the function generate message looks
* ok when prepended to it.
* @throws IllegalArgumentException if the classes are not assignable
*/
public static void isAssignable(Class superType, Class subType, String message) {
notNull(superType, "Type to check against must not be null");
if (subType == null || !superType.isAssignableFrom(subType)) {
throw new IllegalArgumentException(message + subType + " is not assignable to " + superType);
}
}
/**
* Asserts that a specified {@code value} is equal to the given {@code requirement}, throwing
* an {@link IllegalArgumentException} with the given message if not.
*
* @param the type of argument
* @param value the value to check
* @param requirement the requirement that {@code value} must be greater than
* @param msg the message to use for the {@code IllegalArgumentException} if thrown.
* @return {@code value} if greater than the specified {@code requirement}.
* @since 0.12.0
*/
public static > T eq(T value, T requirement, String msg) {
if (compareTo(value, requirement) != 0) {
throw new IllegalArgumentException(msg);
}
return value;
}
private static > int compareTo(T value, T requirement) {
notNull(value, "value cannot be null.");
notNull(requirement, "requirement cannot be null.");
return value.compareTo(requirement);
}
/**
* Asserts that a specified {@code value} is greater than the given {@code requirement}, throwing
* an {@link IllegalArgumentException} with the given message if not.
*
* @param the type of value to check and return if the requirement is met
* @param value the value to check
* @param requirement the requirement that {@code value} must be greater than
* @param msg the message to use for the {@code IllegalArgumentException} if thrown.
* @return {@code value} if greater than the specified {@code requirement}.
* @since 0.12.0
*/
public static > T gt(T value, T requirement, String msg) {
if (!(compareTo(value, requirement) > 0)) {
throw new IllegalArgumentException(msg);
}
return value;
}
/**
* Asserts that a specified {@code value} is less than or equal to the given {@code requirement}, throwing
* an {@link IllegalArgumentException} with the given message if not.
*
* @param the type of value to check and return if the requirement is met
* @param value the value to check
* @param requirement the requirement that {@code value} must be greater than
* @param msg the message to use for the {@code IllegalArgumentException} if thrown.
* @return {@code value} if greater than the specified {@code requirement}.
* @since 0.12.0
*/
public static > T lte(T value, T requirement, String msg) {
if (compareTo(value, requirement) > 0) {
throw new IllegalArgumentException(msg);
}
return value;
}
/**
* Assert a boolean expression, throwing IllegalStateException
* if the test result is false. Call isTrue if you wish to
* throw IllegalArgumentException on an assertion failure.
* Assert.state(id == null, "The id property must not already be initialized");
*
* @param expression a boolean expression
* @param message the exception message to use if the assertion fails
* @throws IllegalStateException if expression is false
*/
public static void state(boolean expression, String message) {
if (!expression) {
throw new IllegalStateException(message);
}
}
/**
* Assert a boolean expression, throwing {@link IllegalStateException}
* if the test result is false.
* Call {@link #isTrue(boolean)} if you wish to
* throw {@link IllegalArgumentException} on an assertion failure.
*
Assert.state(id == null);
*
* @param expression a boolean expression
* @throws IllegalStateException if the supplied expression is false
*/
public static void state(boolean expression) {
state(expression, "[Assertion failed] - this state invariant must be true");
}
/**
* Asserts that the specified {@code value} is not null, otherwise throws an
* {@link IllegalStateException} with the specified {@code msg}. Intended to be used with
* code invariants (as opposed to method arguments, like {@link #notNull(Object)}).
*
* @param value value to assert is not null
* @param msg exception message to use if {@code value} is null
* @param value type
* @return the non-null value
* @throws IllegalStateException with the specified {@code msg} if {@code value} is null.
* @since 0.12.0
*/
public static T stateNotNull(T value, String msg) throws IllegalStateException {
if (value == null) {
throw new IllegalStateException(msg);
}
return value;
}
}