assert.java

来自「spring framework 2.5.4源代码」· Java 代码 · 共 402 行 · 第 1/2 页

	/**
	 * 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 (ObjectUtils.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");
	}

	/**
	 * 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");
	}

	/**
	 * Assert that a collection has elements; that is, it must not be
	 * <code>null</code> and must have at least one element.
	 * <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
	 * @param collection the collection to check
	 * @param message the exception message to use if the assertion fails
	 * @throws IllegalArgumentException if the collection is <code>null</code> or has no elements
	 */
	public static void notEmpty(Collection collection, String message) {
		if (CollectionUtils.isEmpty(collection)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that a collection has elements; that is, it must not be
	 * <code>null</code> and must have at least one element.
	 * <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
	 * @param collection the collection to check
	 * @throws IllegalArgumentException if the collection is <code>null</code> 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 <code>null</code>
	 * and must have at least one entry.
	 * <pre class="code">Assert.notEmpty(map, "Map must have entries");</pre>
	 * @param map the map to check
	 * @param message the exception message to use if the assertion fails
	 * @throws IllegalArgumentException if the map is <code>null</code> or has no entries
	 */
	public static void notEmpty(Map map, String message) {
		if (CollectionUtils.isEmpty(map)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that a Map has entries; that is, it must not be <code>null</code>
	 * and must have at least one entry.
	 * <pre class="code">Assert.notEmpty(map);</pre>
	 * @param map the map to check
	 * @throws IllegalArgumentException if the map is <code>null</code> 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.
	 * <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.
	 * <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);
		}
	}

	/**
	 * Assert that <code>superType.isAssignableFrom(subType)</code> is <code>true</code>.
	 * <pre class="code">Assert.isAssignable(Number.class, myClass);</pre>
	 * @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 <code>superType.isAssignableFrom(subType)</code> is <code>true</code>.
	 * <pre class="code">Assert.isAssignable(Number.class, myClass);</pre>
	 * @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);
		}
	}


	/**
	 * Assert a boolean expression, throwing <code>IllegalStateException</code>
	 * if the test result is <code>false</code>. Call isTrue if you wish to
	 * throw IllegalArgumentException on an assertion failure.
	 * <pre class="code">Assert.state(id == null, "The id property must not already be initialized");</pre>
	 * @param expression a boolean expression
	 * @param message the exception message to use if the assertion fails
	 * @throws IllegalStateException if expression is <code>false</code>
	 */
	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 <code>false</code>.
	 * <p>Call {@link #isTrue(boolean)} if you wish to
	 * throw {@link IllegalArgumentException} on an assertion failure.
	 * <pre class="code">Assert.state(id == null);</pre>
	 * @param expression a boolean expression
	 * @throws IllegalStateException if the supplied expression is <code>false</code>
	 */
	public static void state(boolean expression) {
		state(expression, "[Assertion failed] - this state invariant must be true");
	}

}