/*
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* Copyright 2002-2007 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.walker.infrastructure.utils;
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import java.util.Collection;
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import java.util.Map;
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/**
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* Assertion utility class that assists in validating arguments.
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* Useful for identifying programmer errors early and clearly at runtime.
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*
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* <p>For example, if the contract of a public method states it does not
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* allow <code>null</code> arguments, Assert can be used to validate that
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* contract. Doing this clearly indicates a contract violation when it
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* occurs and protects the class's invariants.
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*
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* <p>Typically used to validate method arguments rather than configuration
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* properties, to check for cases that are usually programmer errors rather than
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* configuration errors. In contrast to config initialization code, there is
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* usally no point in falling back to defaults in such methods.
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*
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* <p>This class is similar to JUnit's assertion library. If an argument value is
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* deemed invalid, an {@link IllegalArgumentException} is thrown (typically).
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* For example:
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*
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* <pre class="code">
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* Assert.notNull(clazz, "The class must not be null");
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* Assert.isTrue(i > 0, "The value must be greater than zero");</pre>
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*
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* Mainly for internal use within the framework; consider Jakarta's Commons Lang
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* >= 2.0 for a more comprehensive suite of assertion utilities.
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*
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* @author Keith Donald
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* @author Juergen Hoeller
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* @author Colin Sampaleanu
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* @author Rob Harrop
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* @since 1.1.2
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*/
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public abstract class Assert {
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/**
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* Assert a boolean expression, throwing <code>IllegalArgumentException</code>
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* if the test result is <code>false</code>.
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* <pre class="code">Assert.isTrue(i > 0, "The value must be greater than zero");</pre>
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* @param expression a boolean expression
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if expression is <code>false</code>
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*/
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public static void isTrue(boolean expression, String message) {
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if (!expression) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert a boolean expression, throwing <code>IllegalArgumentException</code>
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* if the test result is <code>false</code>.
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* <pre class="code">Assert.isTrue(i > 0);</pre>
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* @param expression a boolean expression
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* @throws IllegalArgumentException if expression is <code>false</code>
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*/
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public static void isTrue(boolean expression) {
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isTrue(expression, "[Assertion failed] - this expression must be true");
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}
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/**
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* Assert that an object is <code>null</code> .
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* <pre class="code">Assert.isNull(value, "The value must be null");</pre>
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* @param object the object to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the object is not <code>null</code>
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*/
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public static void isNull(Object object, String message) {
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if (object != null) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that an object is <code>null</code> .
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* <pre class="code">Assert.isNull(value);</pre>
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* @param object the object to check
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* @throws IllegalArgumentException if the object is not <code>null</code>
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*/
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public static void isNull(Object object) {
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isNull(object, "[Assertion failed] - the object argument must be null");
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}
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/**
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* Assert that an object is not <code>null</code> .
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* <pre class="code">Assert.notNull(clazz, "The class must not be null");</pre>
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* @param object the object to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the object is <code>null</code>
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*/
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public static void notNull(Object object, String message) {
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if (object == null) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that an object is not <code>null</code> .
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* <pre class="code">Assert.notNull(clazz);</pre>
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* @param object the object to check
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* @throws IllegalArgumentException if the object is <code>null</code>
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*/
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public static void notNull(Object object) {
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notNull(object, "[Assertion failed] - this argument is required; it must not be null");
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}
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/**
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* Assert that the given String is not empty; that is,
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* it must not be <code>null</code> and not the empty String.
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* <pre class="code">Assert.hasLength(name, "Name must not be empty");</pre>
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* @param text the String to check
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* @param message the exception message to use if the assertion fails
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* @see StringUtils#hasLength
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*/
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public static void hasLength(String text, String message) {
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if (!StringUtils.hasLength(text)) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that the given String is not empty; that is,
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* it must not be <code>null</code> and not the empty String.
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* <pre class="code">Assert.hasLength(name);</pre>
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* @param text the String to check
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* @see StringUtils#hasLength
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*/
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public static void hasLength(String text) {
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hasLength(text,
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"[Assertion failed] - this String argument must have length; it must not be null or empty");
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}
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/**
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* Assert that the given String has valid text content; that is, it must not
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* be <code>null</code> and must contain at least one non-whitespace character.
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* <pre class="code">Assert.hasText(name, "'name' must not be empty");</pre>
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* @param text the String to check
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* @param message the exception message to use if the assertion fails
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* @see StringUtils#hasText
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*/
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public static void hasText(String text, String message) {
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if (!StringUtils.hasText(text)) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that the given String has valid text content; that is, it must not
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* be <code>null</code> and must contain at least one non-whitespace character.
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* <pre class="code">Assert.hasText(name, "'name' must not be empty");</pre>
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* @param text the String to check
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* @see StringUtils#hasText
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*/
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public static void hasText(String text) {
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hasText(text,
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"[Assertion failed] - this String argument must have text; it must not be null, empty, or blank");
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}
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/**
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* Assert that the given text does not contain the given substring.
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* <pre class="code">Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");</pre>
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* @param textToSearch the text to search
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* @param substring the substring to find within the text
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* @param message the exception message to use if the assertion fails
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*/
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public static void doesNotContain(String textToSearch, String substring, String message) {
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if (StringUtils.hasLength(textToSearch) && StringUtils.hasLength(substring) &&
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textToSearch.indexOf(substring) != -1) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that the given text does not contain the given substring.
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* <pre class="code">Assert.doesNotContain(name, "rod");</pre>
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* @param textToSearch the text to search
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* @param substring the substring to find within the text
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*/
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public static void doesNotContain(String textToSearch, String substring) {
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doesNotContain(textToSearch, substring,
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"[Assertion failed] - this String argument must not contain the substring [" + substring + "]");
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}
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/**
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* Assert that an array has elements; that is, it must not be
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* <code>null</code> and must have at least one element.
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* <pre class="code">Assert.notEmpty(array, "The array must have elements");</pre>
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* @param array the array to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the object array is <code>null</code> or has no elements
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*/
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public static void notEmpty(Object[] array, String message) {
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if (ObjectUtils.isEmpty(array)) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that an array has elements; that is, it must not be
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* <code>null</code> and must have at least one element.
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* <pre class="code">Assert.notEmpty(array);</pre>
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* @param array the array to check
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* @throws IllegalArgumentException if the object array is <code>null</code> or has no elements
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*/
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public static void notEmpty(Object[] array) {
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notEmpty(array, "[Assertion failed] - this array must not be empty: it must contain at least 1 element");
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}
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/**
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* Assert that an array has no null elements.
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* Note: Does not complain if the array is empty!
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* <pre class="code">Assert.noNullElements(array, "The array must have non-null elements");</pre>
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* @param array the array to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the object array contains a <code>null</code> element
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*/
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public static void noNullElements(Object[] array, String message) {
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if (array != null) {
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for (int i = 0; i < array.length; i++) {
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if (array[i] == null) {
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throw new IllegalArgumentException(message);
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}
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}
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}
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}
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/**
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* Assert that an array has no null elements.
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* Note: Does not complain if the array is empty!
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* <pre class="code">Assert.noNullElements(array);</pre>
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* @param array the array to check
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* @throws IllegalArgumentException if the object array contains a <code>null</code> element
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*/
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public static void noNullElements(Object[] array) {
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noNullElements(array, "[Assertion failed] - this array must not contain any null elements");
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}
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/**
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* Assert that a collection has elements; that is, it must not be
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* <code>null</code> and must have at least one element.
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* <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
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* @param collection the collection to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the collection is <code>null</code> or has no elements
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*/
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public static void notEmpty(Collection<?> collection, String message) {
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if (CollectionUtils.isEmpty(collection)) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that a collection has elements; that is, it must not be
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* <code>null</code> and must have at least one element.
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* <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
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* @param collection the collection to check
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* @throws IllegalArgumentException if the collection is <code>null</code> or has no elements
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*/
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public static void notEmpty(Collection<?> collection) {
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notEmpty(collection,
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"[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
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}
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/**
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* Assert that a Map has entries; that is, it must not be <code>null</code>
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* and must have at least one entry.
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* <pre class="code">Assert.notEmpty(map, "Map must have entries");</pre>
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* @param map the map to check
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* @param message the exception message to use if the assertion fails
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* @throws IllegalArgumentException if the map is <code>null</code> or has no entries
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*/
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public static void notEmpty(Map<?,?> map, String message) {
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if (CollectionUtils.isEmpty(map)) {
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throw new IllegalArgumentException(message);
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}
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}
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/**
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* Assert that a Map has entries; that is, it must not be <code>null</code>
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* and must have at least one entry.
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* <pre class="code">Assert.notEmpty(map);</pre>
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* @param map the map to check
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* @throws IllegalArgumentException if the map is <code>null</code> or has no entries
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*/
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public static void notEmpty(Map<?,?> map) {
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notEmpty(map, "[Assertion failed] - this map must not be empty; it must contain at least one entry");
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}
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/**
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* Assert that the provided object is an instance of the provided class.
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* <pre class="code">Assert.instanceOf(Foo.class, foo);</pre>
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* @param clazz the required class
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* @param obj the object to check
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* @throws IllegalArgumentException if the object is not an instance of clazz
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* @see Class#isInstance
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*/
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public static void isInstanceOf(Class<?> clazz, Object obj) {
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isInstanceOf(clazz, obj, "");
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}
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/**
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* Assert that the provided object is an instance of the provided class.
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* <pre class="code">Assert.instanceOf(Foo.class, foo);</pre>
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* @param type the type to check against
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* @param obj the object to check
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* @param message a message which will be prepended to the message produced by
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* the function itself, and which may be used to provide context. It should
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* normally end in a ": " or ". " so that the function generate message looks
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* ok when prepended to it.
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* @throws IllegalArgumentException if the object is not an instance of clazz
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* @see Class#isInstance
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*/
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public static void isInstanceOf(Class<?> type, Object obj, String message) {
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notNull(type, "Type to check against must not be null");
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if (!type.isInstance(obj)) {
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throw new IllegalArgumentException(message +
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"Object of class [" + (obj != null ? obj.getClass().getName() : "null") +
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"] must be an instance of " + type);
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}
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}
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/**
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* Assert that <code>superType.isAssignableFrom(subType)</code> is <code>true</code>.
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* <pre class="code">Assert.isAssignable(Number.class, myClass);</pre>
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* @param superType the super type to check
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* @param subType the sub type to check
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* @throws IllegalArgumentException if the classes are not assignable
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*/
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public static void isAssignable(Class<?> superType, Class<?> subType) {
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isAssignable(superType, subType, "");
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}
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/**
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* Assert that <code>superType.isAssignableFrom(subType)</code> is <code>true</code>.
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* <pre class="code">Assert.isAssignable(Number.class, myClass);</pre>
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* @param superType the super type to check against
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* @param subType the sub type to check
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* @param message a message which will be prepended to the message produced by
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* the function itself, and which may be used to provide context. It should
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* normally end in a ": " or ". " so that the function generate message looks
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* ok when prepended to it.
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* @throws IllegalArgumentException if the classes are not assignable
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*/
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public static void isAssignable(Class<?> superType, Class<?> subType, String message) {
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notNull(superType, "Type to check against must not be null");
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if (subType == null || !superType.isAssignableFrom(subType)) {
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throw new IllegalArgumentException(message + subType + " is not assignable to " + superType);
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}
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}
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/**
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* Assert a boolean expression, throwing <code>IllegalStateException</code>
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* if the test result is <code>false</code>. Call isTrue if you wish to
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* throw IllegalArgumentException on an assertion failure.
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* <pre class="code">Assert.state(id == null, "The id property must not already be initialized");</pre>
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* @param expression a boolean expression
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* @param message the exception message to use if the assertion fails
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* @throws IllegalStateException if expression is <code>false</code>
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*/
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public static void state(boolean expression, String message) {
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if (!expression) {
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throw new IllegalStateException(message);
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}
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}
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/**
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* Assert a boolean expression, throwing {@link IllegalStateException}
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* if the test result is <code>false</code>.
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* <p>Call {@link #isTrue(boolean)} if you wish to
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* throw {@link IllegalArgumentException} on an assertion failure.
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* <pre class="code">Assert.state(id == null);</pre>
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* @param expression a boolean expression
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* @throws IllegalStateException if the supplied expression is <code>false</code>
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*/
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public static void state(boolean expression) {
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state(expression, "[Assertion failed] - this state invariant must be true");
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}
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}
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