Assert.java

package com.xiaoleilu.hutool.lang;

import java.util.Collection;
import java.util.Map;

import com.xiaoleilu.hutool.util.ArrayUtil;
import com.xiaoleilu.hutool.util.CollectionUtil;
import com.xiaoleilu.hutool.util.StrUtil;

/**
 * 断言<br>
 * 断言某些对象或值是否符合规定，否则抛出异常。经常用于做变量检查
 * @author Looly
 *
 */
public final class Assert {
	
	private Assert() {}
	
	/**
	 * 断言是否为真，如果为 {@code false} 抛出 {@code IllegalArgumentException} 异常<br>
	 * 
	 * <pre class="code">
	 * Assert.isTrue(i > 0, "The value must be greater than zero");
	 * </pre>
	 * 
	 * @param expression 波尔值
	 * @param message 错误抛出异常附带的消息
	 * @throws IllegalArgumentException if expression is {@code false}
	 */
	public static void isTrue(boolean expression, String message) {
		if (!expression) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * 断言是否为真，如果为 {@code false} 抛出 {@code IllegalArgumentException} 异常<br>
	 * 
	 * <pre class="code">
	 * Assert.isTrue(i > 0, "The value must be greater than zero");
	 * </pre>
	 * 
	 * @param expression 波尔值
	 * @throws IllegalArgumentException if expression is {@code false}
	 */
	public static void isTrue(boolean expression) {
		isTrue(expression, "[Assertion failed] - this expression must be true");
	}

	/**
	 * Assert that an object is {@code null} .
	 * 
	 * <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}
	 */
	public static void isNull(Object object, String message) {
		if (object != null) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that an object is {@code null} .
	 * 
	 * <pre class="code">
	 * Assert.isNull(value);
	 * </pre>
	 * 
	 * @param object the object to check
	 * @throws IllegalArgumentException if the object is not {@code null}
	 */
	public static void isNull(Object object) {
		isNull(object, "[Assertion failed] - the object argument must be null");
	}

	/**
	 * Assert that an object is not {@code null} .
	 * 
	 * <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}
	 */
	public static void notNull(Object object, String message) {
		if (object == null) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that an object is not {@code null} .
	 * 
	 * <pre class="code">
	 * Assert.notNull(clazz);
	 * </pre>
	 * 
	 * @param object the object to check
	 * @throws IllegalArgumentException if the object is {@code null}
	 */
	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} 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 StrUtil#isNotEmpty
	 */
	public static void notEmpty(String text, String message) {
		if (StrUtil.isEmpty(text)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that the given String is not empty; that is, it must not be {@code null} and not the empty String.
	 * 
	 * <pre class="code">
	 * Assert.hasLength(name);
	 * </pre>
	 * 
	 * @param text the String to check
	 * @see StrUtil#isNotEmpty
	 */
	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 the given String has valid text content; that is, it must not be {@code null} 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 StrUtil#isNotBlank
	 */
	public static void notBlank(String text, String message) {
		if (StrUtil.isBlank(text)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that the given String has valid text content; that is, it must not be {@code null} 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 StrUtil#isNotBlank
	 */
	public static void notBlank(String text) {
		notBlank(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 notContain(String textToSearch, String substring, String message) {
		if (StrUtil.isNotEmpty(textToSearch) && StrUtil.isNotEmpty(substring) && textToSearch.contains(substring)) {
			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 notContain(String textToSearch, String substring) {
		notContain(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} 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} or has no elements
	 */
	public static void notEmpty(Object[] array, String message) {
		if (ArrayUtil.isEmpty(array)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that an array has elements; that is, it must not be {@code null} 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} 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} element
	 */
	public static void noNullElements(Object[] array, String message) {
		if (array != null) {
			for (Object element : array) {
				if (element == 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} 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} 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} or has no elements
	 */
	public static void notEmpty(Collection<?> collection, String message) {
		if (CollectionUtil.isEmpty(collection)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that a collection has elements; that is, it must not be {@code null} 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} 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} 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} or has no entries
	 */
	public static void notEmpty(Map<?, ?> map, String message) {
		if (CollectionUtil.isEmpty(map)) {
			throw new IllegalArgumentException(message);
		}
	}

	/**
	 * Assert that a Map has entries; that is, it must not be {@code null} 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} 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(
					(StrUtil.isNotEmpty(message) ? message + " " : "") + "Object of class [" + (obj != null ? obj.getClass().getName() : "null") + "] must be an instance of " + type);
		}
	}

	/**
	 * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}.
	 * 
	 * <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)} is {@code true}.
	 * 
	 * <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} if the test result is {@code false}. 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}
	 */
	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}.
	 * <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}
	 */
	public static void state(boolean expression) {
		state(expression, "[Assertion failed] - this state invariant must be true");
	}
}