org.tinygroup.commons.tools

Class Assert

java.lang.Object

org.tinygroup.commons.tools.Assert

public final class Assert
extends Object

断言工具，用来实现Fail-Fast。

注意事项：

• Assertion是用来明确设置程序中的条件和约定的，它是一种程序员之间交流的工具，而不是和最终用户交流的工具。
• 一个经过完整单元测试的正确程序，不应该使任何一条assertion失败。
• 应避免过于复杂的assertion条件，而占用过多的运行时间。除非Assertion失败。
• Assertion的出现异常信息不是给最终用户看的，因此没必要写得过于详细，更没必要考虑国际化的问题，以至于浪费CPU的时间。 例如下面的语句是要避免的：

   assertTrue(type instanceof MyType, "Unsupported type: " + type);
   

  可以替换成：

   assertTrue(type instanceof MyType, "Unsupported type: %s", type);
   

  这样，当assertion顺利通过时，不会占用CPU时间。

此外，部分方法具有返回值，以方便编程，例如：

 void foo(String param) {
     bar(assertNotNull(param));
 }

 int bar(String param) {
     if (true) {
         ...
     }

     return unreachableCode();
 }
 

Author:

renhui

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Assert.ExceptionType Assertion错误类型。

Constructor Summary

Constructors

Constructor and Description
Assert()

Method Summary

Modifier and Type	Method and Description
static <T> T	assertNotNull(T object) 确保对象不为空，否则抛出IllegalArgumentException。
static <T> T	assertNotNull(T object, Assert.ExceptionType exceptionType, String message, Object... args) 确保对象不为空，否则抛出指定异常，默认为IllegalArgumentException。
static <T> T	assertNotNull(T object, String message, Object... args) 确保对象不为空，否则抛出IllegalArgumentException。
static <T> T	assertNull(T object) 确保对象为空，否则抛出IllegalArgumentException。
static <T> T	assertNull(T object, Assert.ExceptionType exceptionType, String message, Object... args) 确保对象为空，否则抛出指定异常，默认为IllegalArgumentException。
static <T> T	assertNull(T object, String message, Object... args) 确保对象为空，否则抛出IllegalArgumentException。
static void	assertTrue(boolean expression) 确保表达式为真，否则抛出IllegalArgumentException。
static void	assertTrue(boolean expression, Assert.ExceptionType exceptionType, String message, Object... args) 确保表达式为真，否则抛出指定异常，默认为IllegalArgumentException。
static void	assertTrue(boolean expression, String message, Object... args) 确保表达式为真，否则抛出IllegalArgumentException。
static <T> T	fail() 未预料的失败。
static <T> T	fail(String message, Object... args) 未预料的失败。
static void	hasLength(String text) Assert that the given String is not empty; that is, it must not be null and not the empty String.
static void	hasLength(String text, String message) Assert that the given String is not empty; that is, it must not be null and not the empty String.
static void	hasText(String text) Assert that the given String has valid text content; that is, it must not be null and must contain at least one non-whitespace character.
static void	hasText(String text, String message) Assert that the given String has valid text content; that is, it must not be null and must contain at least one non-whitespace character.
static void	isAssignable(Class superType, Class subType) Assert that superType.isAssignableFrom(subType) is true.
static void	isAssignable(Class superType, Class subType, String message) Assert that superType.isAssignableFrom(subType) is true.
static void	notEmpty(Object[] array, String message)
static <T> T	unexpectedException(Throwable e) 不可能发生的异常。
static <T> T	unexpectedException(Throwable e, String message, Object... args) 不可能发生的异常。
static <T> T	unreachableCode() 不可能到达的代码。
static <T> T	unreachableCode(String message, Object... args) 不可能到达的代码。
static <T> T	unsupportedOperation() 不支持的操作。
static <T> T	unsupportedOperation(String message, Object... args) 不支持的操作。

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Assert

public Assert()

Method Detail

assertNotNull

public static <T> T assertNotNull(T object)

确保对象不为空，否则抛出IllegalArgumentException。

assertNotNull

public static <T> T assertNotNull(T object,
                                  String message,
                                  Object... args)

确保对象不为空，否则抛出IllegalArgumentException。

assertNotNull

public static <T> T assertNotNull(T object,
                                  Assert.ExceptionType exceptionType,
                                  String message,
                                  Object... args)

确保对象不为空，否则抛出指定异常，默认为IllegalArgumentException。

notEmpty

public static void notEmpty(Object[] array,
                            String message)

assertNull

public static <T> T assertNull(T object)

确保对象为空，否则抛出IllegalArgumentException。

assertNull

public static <T> T assertNull(T object,
                               String message,
                               Object... args)

确保对象为空，否则抛出IllegalArgumentException。

assertNull

public static <T> T assertNull(T object,
                               Assert.ExceptionType exceptionType,
                               String message,
                               Object... args)

确保对象为空，否则抛出指定异常，默认为IllegalArgumentException。

assertTrue

public static void assertTrue(boolean expression)

确保表达式为真，否则抛出IllegalArgumentException。

assertTrue

public static void assertTrue(boolean expression,
                              String message,
                              Object... args)

确保表达式为真，否则抛出IllegalArgumentException。

assertTrue

public static void assertTrue(boolean expression,
                              Assert.ExceptionType exceptionType,
                              String message,
                              Object... args)

确保表达式为真，否则抛出指定异常，默认为IllegalArgumentException。

unreachableCode

public static <T> T unreachableCode()

不可能到达的代码。

unreachableCode

public static <T> T unreachableCode(String message,
                                    Object... args)

不可能到达的代码。

unexpectedException

public static <T> T unexpectedException(Throwable e)

不可能发生的异常。

unexpectedException

public static <T> T unexpectedException(Throwable e,
                                        String message,
                                        Object... args)

不可能发生的异常。

fail

public static <T> T fail()

未预料的失败。

fail

public static <T> T fail(String message,
                         Object... args)

未预料的失败。

unsupportedOperation

public static <T> T unsupportedOperation()

不支持的操作。

unsupportedOperation

public static <T> T unsupportedOperation(String message,
                                         Object... args)

不支持的操作。

hasLength

public static void hasLength(String text,
                             String message)

Assert that the given String is not empty; that is, it must not be null and not the empty String.

Assert.hasLength(name, "Name must not be empty");

Parameters:

text - the String to check

message - the exception message to use if the assertion fails

See Also:

StringUtils#hasLength

hasLength

public static void hasLength(String text)

Assert that the given String is not empty; that is, it must not be null and not the empty String.

Assert.hasLength(name);

Parameters:

text - the String to check

See Also:

StringUtils#hasLength

hasText

public static void hasText(String text,
                           String message)

Assert that the given String has valid text content; that is, it must not be null and must contain at least one non-whitespace character.

Assert.hasText(name, "'name' must not be empty");

Parameters:

text - the String to check

message - the exception message to use if the assertion fails

See Also:

StringUtils#hasText

hasText

public static void hasText(String text)

Assert that the given String has valid text content; that is, it must not be null and must contain at least one non-whitespace character.

Assert.hasText(name, "'name' must not be empty");

Parameters:

text - the String to check

See Also:

StringUtils#hasText

isAssignable

public static void isAssignable(Class superType,
                                Class subType)

Assert that superType.isAssignableFrom(subType) is true.

Assert.isAssignable(Number.class, myClass);

Parameters:

superType - the super type to check

subType - the sub type to check

Throws:

IllegalArgumentException - if the classes are not assignable

isAssignable

public static void isAssignable(Class superType,
                                Class subType,
                                String message)

Assert that superType.isAssignableFrom(subType) is true.

Assert.isAssignable(Number.class, myClass);

Parameters:

superType - the super type to check against

subType - the sub type to check

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