org.batoo.common.util.Assert Maven / Gradle / Ivy
/*
* Copyright (c) 2012 - Batoo Software ve Consultancy Ltd.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.batoo.common.util;
import java.util.Collection;
import java.util.Map;
/**
* Assertion utility class that assists in validating arguments. Useful for identifying programmer errors early and clearly at runtime.
*
*
* For example, if the contract of a public method states it does not allow null arguments, Assert can be used to validate that
* contract. Doing this clearly indicates a contract violation when it occurs and protects the class's invariants.
*
*
* Typically used to validate method arguments rather than configuration properties, to check for cases that are usually programmer errors
* rather than configuration errors. In contrast to config initialization code, there is usally no point in falling back to defaults in such
* methods.
*
*
* This class is similar to JUnit's assertion library. If an argument value is deemed invalid, an {@link IllegalArgumentException} is thrown
* (typically). For example:
*
*
* Assert.notNull(clazz, "The class must not be null");
* Assert.isTrue(i > 0, "The value must be greater than zero");
*
*
* Mainly for internal use within the framework; consider Jakarta's Commons Lang >= 2.0 for a more comprehensive suite of assertion
* utilities.
*
*
* The original code is based on org.springframework.util.Assert
*
* @author hceylan
* @since 2.0.1
*/
public abstract class Assert {
/**
* 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) {
Assert.doesNotContain(textToSearch, substring, "[Assertion failed] - this String argument must not contain the substring [" + substring + "]");
}
/**
* 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 (StringUtils.hasLength(textToSearch) && StringUtils.hasLength(substring) && (textToSearch.indexOf(substring) != -1)) {
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 StringUtils#hasLength
*/
public static void hasLength(String text) {
Assert.hasLength(text, "[Assertion failed] - this String argument must have length; it must not be null or empty");
}
/**
* 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 StringUtils#hasLength
*/
public static void hasLength(String text, String message) {
if (!StringUtils.hasLength(text)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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 StringUtils#hasText
*/
public static void hasText(String text) {
Assert.hasText(text, "[Assertion failed] - this String argument must have text; it must not be null, empty, or blank");
}
/**
* 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
* @param message
* the exception message to use if the assertion fails
* @see StringUtils#hasText
*/
public static void hasText(String text, String message) {
if (!StringUtils.hasText(text)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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) {
Assert.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) {
Assert.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);
}
}
/**
* Assert that the provided object is an instance of the provided class.
*
*
* Assert.instanceOf(Foo.class, foo);
*
*
* @param clazz
* the required class
* @param obj
* the object to check
* @throws IllegalArgumentException
* if the object is not an instance of clazz
* @see Class#isInstance
*/
public static void isInstanceOf(Class clazz, Object obj) {
Assert.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 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.
* @throws IllegalArgumentException
* if the object is not an instance of clazz
* @see Class#isInstance
*/
public static void isInstanceOf(Class type, Object obj, String message) {
Assert.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);
}
}
/**
* 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) {
Assert.isNull(object, "[Assertion failed] - the object argument must be null");
}
/**
* 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 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) {
Assert.isTrue(expression, "[Assertion failed] - this expression must be true");
}
/**
* 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 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) {
Assert.noNullElements(array, "[Assertion failed] - this array must not contain any null elements");
}
/**
* 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 (final Object element : array) {
if (element == null) {
throw new IllegalArgumentException(message);
}
}
}
}
/**
* Assert that a string is not null, and has characters other than white space characters.
*
*
* Assert.notEmpty(string, "String must not be empty");
*
*
* @param string
* the string to check
* @throws IllegalArgumentException
* if the string is blank
*/
public static void notBlank(String string) {
Assert.notBlank(string, "[Assertion failed] - this string must not be blank or null");
}
/**
* Assert that a string is not null, and has charachters other than white space characters.
*
*
* Assert.notEmpty(string, "String must have elements");
*
*
* @param string
* the string to check
* @param message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the string is empty
*/
public static void notBlank(String string, String message) {
if (StringUtils.isBlank(string)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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) {
Assert.notEmpty(collection, "[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
}
/**
* 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 message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the collection is null or has no elements
*/
public static void notEmpty(Collection collection, String message) {
if (CollectionUtils.isEmpty(collection)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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) {
Assert.notEmpty(map, "[Assertion failed] - this map must not be empty; it must contain at least one entry");
}
/**
* 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 message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the map is null or has no entries
*/
public static void notEmpty(Map map, String message) {
if (CollectionUtils.isEmpty(map)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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) {
Assert.notEmpty(array, "[Assertion failed] - this array must not be empty: it must contain at least 1 element");
}
/**
* 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
* @throws IllegalArgumentException
* if the object array is null or has no elements
*/
public static void notEmpty(Object[] array, String message) {
if (ObjectUtils.isEmpty(array)) {
throw new IllegalArgumentException(message);
}
}
/**
* 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) {
Assert.notNull(object, "[Assertion failed] - this argument is required; it must not 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 message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the object is null
*/
public static void notNull(Object object, String message) {
if (object == null) {
throw new IllegalArgumentException(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) {
Assert.state(expression, "[Assertion failed] - this state invariant must be true");
}
/**
* 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);
}
}
}