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Some commonly used methods in java
/**
* reference from spring framework
*/
package com.gitee.cliveyuan.tools;
import java.util.Collection;
import java.util.Map;
/**
* Assertion utility class that assists in validating arguments. Useful for
* identifying programmer errors early and clearly at runtime.
*
*
* For example, if the contract of a public method states it does not allow
* {@code null} arguments, Assert can be used to validate that contract. Doing
* this clearly indicates a contract violation when it occurs and protects the
* class's invariants.
*
*
* Typically used to validate method arguments rather than configuration
* properties, to check for cases that are usually programmer errors rather than
* configuration errors. In contrast to config initialization code, there is
* usally no point in falling back to defaults in such methods.
*
*
* This class is similar to JUnit's assertion library. If an argument value is
* deemed invalid, an {@link IllegalArgumentException} is thrown (typically).
* For example:
*
*
* Assert.notNull(clazz, "The class must not be null");
* Assert.isTrue(i < 0, "The value must be greater than zero");
*
*
* Mainly for internal use within the framework; consider Apache's Commons Lang
* >= 2.0 for a more comprehensive suite of assertion utilities.
*
* @author Keith Donald
* @author Juergen Hoeller
* @author Colin Sampaleanu
* @author Rob Harrop
* @author Clive Yuan
* @since 1.1.2
*/
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 StringTools#hasLength
*/
public static void hasLength(String text, String message) {
if (!StringTools.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 StringTools#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 the given String has valid text content; that is, it must not
* be {@code null} and must contain at least one non-whitespace character.
*
*
* Assert.hasText(name, "'name' must not be empty");
*
*
* @param text the String to check
* @param message the exception message to use if the assertion fails
* @see StringTools#hasText
*/
public static void hasText(String text, String message) {
if (!StringTools.hasText(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.
*
*
* Assert.hasText(name, "'name' must not be empty");
*
*
* @param text the String to check
* @see StringTools#hasText
*/
public static void hasText(String text) {
hasText(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.
*
*
* Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
*
*
* @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 doesNotContain(String textToSearch, String substring, String message) {
if (StringTools.hasLength(textToSearch) && StringTools.hasLength(substring)
&& textToSearch.contains(substring)) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the given text does not contain the given substring.
*
*
* Assert.doesNotContain(name, "rod");
*
*
* @param textToSearch the text to search
* @param substring the substring to find within the text
*/
public static void doesNotContain(String textToSearch, String substring) {
doesNotContain(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.
*
*
* 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 an array has elements; that is, it must not be {@code null}
* and must have at least one element.
*
*
* Assert.notEmpty(array);
*
*
* @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!
*
*
* Assert.noNullElements(array, "The array must have non-null elements");
*
*
* @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!
*
*
* Assert.noNullElements(array);
*
*
* @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.
*
*
* 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);
*
*
* @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.
*
*
* Assert.instanceOf(Foo.class, foo);
*
*
* @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(
(StringTools.hasLength(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}.
*
*
* Assert.isAssignable(Number.class, myClass);
*
*
* @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}.
*
*
* Assert.isAssignable(Number.class, myClass);
*
*
* @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.
*
*
* Assert.state(id == null, "The id property must not already be initialized");
*
*
* @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}.
*
* Call {@link #isTrue(boolean)} if you wish to throw
* {@link IllegalArgumentException} on an assertion failure.
*
*
* Assert.state(id == null);
*
*
* @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");
}
public static void notEmpty(String str) {
notEmpty(str, "str can't be empty");
}
/**
* 字符串不能为空
*
* @param str 字符串
* @param message 消息
*/
public static void notEmpty(String str, String message) {
if (StringTools.isEmpty(str)) {
throw new IllegalArgumentException(message);
}
}
public static void notBlank(String str) {
notBlank(str, "str cant't be blank");
}
/**
* 字符串不能为空(包括空格)
*
* @param str 字符串
* @param message 消息
*/
public static void notBlank(String str, String message) {
if (StringTools.isBlank(str)) {
throw new IllegalArgumentException(message);
}
}
}