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Jave Web Validator Framework
/*
* Copyright 2016-2017, Youqian Yue ([email protected]).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.devefx.validator.util;
import java.util.Collection;
import java.util.Map;
public abstract class Assert {
/**
* Assert a boolean expression, throwing {@code IllegalArgumentException}
* if the test result is {@code false}.
* Assert.isTrue(i > 0, "The value must be greater than zero");
* @param expression a boolean expression
* @param message the exception message to use if the assertion fails
* @throws IllegalArgumentException if expression is {@code false}
*/
public static void isTrue(boolean expression, String message) {
if (!expression) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert a boolean expression, throwing {@code IllegalArgumentException}
* if the test result is {@code false}.
* Assert.isTrue(i > 0);
* @param expression a boolean expression
* @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} .
* Assert.isNull(value, "The value must be null");
* @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} .
* Assert.isNull(value);
* @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} .
* Assert.notNull(clazz, "The class must not be null");
* @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} .
* Assert.notNull(clazz);
* @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.
* Assert.hasLength(name, "Name must not be empty");
* @param text the String to check
* @param message the exception message to use if the assertion fails
* @see StringUtils#hasLength
*/
public static void hasLength(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} and not the empty String.
* Assert.hasLength(name);
* @param text the String to check
* @see StringUtils#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 an array has elements; that is, it must not be
* {@code null} and must have at least one element.
* Assert.notEmpty(array, "The array must have elements");
* @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 (array == null || array.length == 0) {
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.
* Assert.notEmpty(collection, "Collection must have elements");
* @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 (collection == null || collection.isEmpty()) {
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.
* Assert.notEmpty(collection, "Collection must have elements");
* @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.
* Assert.notEmpty(map, "Map must have entries");
* @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 (map == null || map.isEmpty()) {
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.
* Assert.notEmpty(map);
* @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.
* Assert.instanceOf(Foo.class, foo, "Foo expected");
* @param type the type to check against
* @param obj the object to check
* @param message a message which will be prepended to provide further context.
* If it is empty or ends in ":" or ";" or "," or ".", a full exception message
* will be appended. If it ends in a space, the name of the offending object's
* type will be appended. In any other case, a ":" with a space and the name
* of the offending object's type will be appended.
* @throws IllegalArgumentException if the object is not an instance of type
*/
public static void isInstanceOf(Class type, Object obj, String message) {
notNull(type, "Type to check against must not be null");
if (!type.isInstance(obj)) {
instanceCheckFailed(type, obj, message);
}
}
private static void instanceCheckFailed(Class type, Object obj, String msg) {
String className = (obj != null ? obj.getClass().getName() : "null");
String result = "";
boolean defaultMessage = true;
if (StringUtils.hasLength(msg)) {
if (endsWithSeparator(msg)) {
result = msg + " ";
}
else {
result = messageWithTypeName(msg, className);
defaultMessage = false;
}
}
if (defaultMessage) {
result = result + ("Object of class [" + className + "] must be an instance of " + type);
}
throw new IllegalArgumentException(result);
}
private static boolean endsWithSeparator(String msg) {
return (msg.endsWith(":") || msg.endsWith(";") || msg.endsWith(",") || msg.endsWith("."));
}
private static String messageWithTypeName(String msg, Object typeName) {
return msg + (msg.endsWith(" ") ? "" : ": ") + typeName;
}
}