Package 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).

  • Constructor Summary

    Constructors
    Constructor
    Description
    Assert()
     

  • Method Summary

    Modifier and Type
    Method
    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 Details

    • Assert

      public Assert()

  • Method Details

    • 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:

    • 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