Assert.java

/*
 * @(#)Assert.java 2012-8-10 下午2:48:06
 *
 * Copyright (c) 2011-2012 Makersoft.org all rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *
 */
package org.makersoft.shards.utils;

/**
 * Assertion utility class that assists in validating arguments.
 * 
 * @author Feng Kuok
 */
public class Assert {
	
	private 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 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");
	}

}