package com.mcxiaoke.minicat.util;
import java.util.Collection;
/**
* @author mcxiaoke
* @version 2.0 2012-2-23 下午12:45:21
*/
public final class Assert {
/**
* Assert a boolean expression, throwing
* <code>IllegalArgumentException</code> if the test result is
* <code>false</code>.
* <p/>
* <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>.
* <p/>
* <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 not <code>null</code> .
* <p/>
* <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> .
* <p/>
* <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");
}
public static void notEmpty(Collection<?> e, String message) {
if (e == null || e.isEmpty()) {
throw new NullPointerException(message);
}
}
public static void notEmpty(Object[] array, String message) {
if (array == null || array.length == 0) {
throw new NullPointerException(message);
}
}
public static void notEmpty(Collection<?> e) {
notEmpty(e,
"[Assertion failed] - this collection must not be null or empty");
}
public static void notEmpty(Object[] array) {
notEmpty(array,
"[Assertion failed] - this array must not be null or empty");
}
/**
* Assert that the given String is not empty; that is, it must not be
* <code>null</code> and not the empty String.
* <p/>
* <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 StringUtils#hasLength
*/
public static void notEmpty(String text, String message) {
if (!StringUtils.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.
* <p/>
* <pre class="code">
* Assert.hasLength(name);
* </pre>
*
* @param text the String to check
* @see StringUtils#hasLength
*/
public static void notEmpty(String text) {
notEmpty(
text,
"[Assertion failed] - this String argument must have length; it must not be null or empty");
}
/**
* Assert that an array has no null elements. Note: Does not complain if the
* array is empty!
* <p/>
* <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!
* <p/>
* <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");
}
/**
* Assert that the provided object is an instance of the provided class.
* <p/>
* <pre class="code">
* Assert.instanceOf(Foo.class, foo);
* </pre>
*
* @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) {
isInstanceOf(clazz, obj, "");
}
/**
* Assert that the provided object is an instance of the provided class.
* <p/>
* <pre class="code">
* Assert.instanceOf(Foo.class, foo);
* </pre>
*
* @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) {
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);
}
}
}