spark.utils

Class Assert

java.lang.Object

spark.utils.Assert

public abstract class Assert
extends Object

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 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 usually 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 IllegalArgumentException is thrown (typically).

Author:

Keith Donald, Juergen Hoeller, Colin Sampaleanu, Rob Harrop Code copied from Spring source. Modifications made (mostly removal of methods) by Per Wendel.

Constructor Summary

Constructors

Constructor and Description
Assert()

Method Summary

Modifier and Type	Method and Description
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	isTrue(boolean expression, String message) Assert a boolean expression, throwing IllegalArgumentException if the test result is false.
static void	notEmpty(Object[] array, String message) Assert that an array has elements; that is, it must not be null and must have at least one element.
static void	notNull(Object object) Assert that an object is not null .
static void	notNull(Object object, String message) Assert that an object is not null .
static void	state(boolean expression, String message) Assert a boolean expression, throwing IllegalStateException if the test result is false.

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

isTrue

public static void isTrue(boolean expression,
                          String message)

Assert a boolean expression, throwing IllegalArgumentException if the test result is false.

Assert.isTrue(i > 0, "The value must be greater than zero");

Parameters:

expression - a boolean expression

message - the exception message to use if the assertion fails

Throws:

IllegalArgumentException - if expression is false

notNull

public static void notNull(Object object,
                           String message)

Assert that an object is not null .

Assert.notNull(clazz, "The class must not be null");

Parameters:

object - the object to check

message - the exception message to use if the assertion fails

Throws:

IllegalArgumentException - if the object is null

notNull

public static void notNull(Object object)

Assert that an object is not null .

Assert.notNull(clazz);

Parameters:

object - the object to check

Throws:

IllegalArgumentException - if the object is null

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(java.lang.CharSequence)

notEmpty

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

Assert that an array has elements; that is, it must not be null and must have at least one element.

Assert.notEmpty(array, "The array must have elements");

Parameters:

array - the array to check

message - the exception message to use if the assertion fails

Throws:

IllegalArgumentException - if the object array is null or has no elements

state

public static void state(boolean expression,
                         String message)

Assert a boolean expression, throwing IllegalStateException if the test result is 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");

Parameters:

expression - a boolean expression

message - the exception message to use if the assertion fails

Throws:

IllegalStateException - if expression is false