package io.craft.atom.util;
/**
* Assertion utility class that assists in validating arguments.
* Useful for identifying programmer errors early and clearly at runtime.
*
* <p>For example, if the contract of a public method states it does not
* allow <code>null</code> 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.
*
* <p>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.
*
* <p>This class is similar to JUnit's assertion library. If an argument value is
* deemed invalid, an {@link IllegalArgumentException} is thrown (typically).
* For example:
*
* <pre>
* Assert.notNull(clazz, "The class must not be null");
* Assert.isTrue(i > 0, "The value must be greater than zero");
* </pre>
*
* @author Keith Donald
* @author Juergen Hoeller
* @author Colin Sampaleanu
* @author Rob Harrop
* @author mindwind
* @version 1.0, Oct 17, 2013
*/
public abstract class Assert {
/**
* Assert a boolean expression, throwing
* <code>IllegalArgumentException</code> if the test result is
* <code>false</code>.
*
* <pre class="code">
* Assert.isTrue(i > 0, "The value must be greater than zero");
* </pre>
*
* @param expression
* a boolean expression
* @param message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if expression is <code>false</code>
*/
public static void isTrue(boolean expression, String message) {
if (!expression) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert a boolean expression, throwing
* <code>IllegalArgumentException</code> if the test result is
* <code>false</code>.
*
* <pre class="code">
* Assert.isTrue(i > 0);
* </pre>
*
* @param expression
* a boolean expression
* @throws IllegalArgumentException
* if expression is <code>false</code>
*/
public static void isTrue(boolean expression) {
isTrue(expression, "[Assertion failed] - this expression must be true");
}
/**
* Assert that an object is <code>null</code> .
*
* <pre class="code">
* Assert.isNull(value, "The value must be null");
* </pre>
*
* @param object
* the object to check
* @param message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the object is not <code>null</code>
*/
public static void isNull(Object object, String message) {
if (object != null) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that an object is <code>null</code> .
*
* <pre class="code">
* Assert.isNull(value);
* </pre>
*
* @param object
* the object to check
* @throws IllegalArgumentException
* if the object is not <code>null</code>
*/
public static void isNull(Object object) {
isNull(object, "[Assertion failed] - the object argument must be null");
}
/**
* Assert that an object is not <code>null</code> .
*
* <pre class="code">
* Assert.notNull(clazz, "The class must not be null");
* </pre>
*
* @param object
* the object to check
* @param message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the object is <code>null</code>
*/
public static void notNull(Object object, String message) {
if (object == null) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that an object is not <code>null</code> .
*
* <pre class="code">
* Assert.notNull(clazz);
* </pre>
*
* @param object
* the object to check
* @throws IllegalArgumentException
* if the object is <code>null</code>
*/
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
* <code>null</code> and not the empty String.
*
* <pre class="code">
* Assert.hasLength(name, "Name must not be empty");
* </pre>
*
* @param text
* the String to check
* @param message
* the exception message to use if the assertion fails
* @see StringUtil#hasLength
*/
public static void hasLength(String text, String message) {
if (!StringUtil.hasLength(text)) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given String is not empty; that is, it must not be
* <code>null</code> and not the empty String.
*
* <pre class="code">
* Assert.hasLength(name);
* </pre>
*
* @param text
* the String to check
* @see StringUtil#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 <code>null</code> and must contain at least one non-whitespace
* character.
*
* <pre class="code">
* Assert.hasText(name, "'name' must not be empty");
* </pre>
*
* @param text
* the String to check
* @param message
* the exception message to use if the assertion fails
* @see StringUtil#hasText
*/
public static void hasText(String text, String message) {
if (!StringUtil.hasText(text)) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given String has valid text content; that is, it must not
* be <code>null</code> and must contain at least one non-whitespace
* character.
*
* <pre class="code">
* Assert.hasText(name, "'name' must not be empty");
* </pre>
*
* @param text
* the String to check
* @see StringUtil#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.
*
* <pre class="code">
* Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
* </pre>
*
* @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 (StringUtil.hasLength(textToSearch)
&& StringUtil.hasLength(substring)
&& textToSearch.indexOf(substring) != -1) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given text does not contain the given substring.
*
* <pre class="code">
* Assert.doesNotContain(name, "rod");
* </pre>
*
* @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
* <code>null</code> and must have at least one element.
*
* <pre class="code">
* Assert.notEmpty(array, "The array must have elements");
* </pre>
*
* @param array
* the array to check
* @param message
* the exception message to use if the assertion fails
* @throws IllegalArgumentException
* if the object array is <code>null</code> or has no elements
*/
public static void notEmpty(Object[] array, String message) {
if (isEmpty(array)) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that an array has elements; that is, it must not be
* <code>null</code> and must have at least one element.
*
* <pre class="code">
* Assert.notEmpty(array);
* </pre>
*
* @param array
* the array to check
* @throws IllegalArgumentException
* if the object array is <code>null</code> 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");
}
private static boolean isEmpty(Object[] array) {
return (array == null || array.length == 0);
}
/**
* Assert that an array has no null elements. Note: Does not complain if the
* array is empty!
*
* <pre class="code">
* Assert.noNullElements(array, "The array must have non-null elements");
* </pre>
*
* @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 <code>null</code> 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!
*
* <pre class="code">
* Assert.noNullElements(array);
* </pre>
*
* @param array
* the array to check
* @throws IllegalArgumentException
* if the object array contains a <code>null</code> element
*/
public static void noNullElements(Object[] array) {
noNullElements(array,
"[Assertion failed] - this array must not contain any null elements");
}
}