Package spark.utils

Class Assert

  • public abstract class Assert
extends java.lang.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

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void hasLength​(java.lang.String text, java.lang.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, java.lang.String message)
      Assert a boolean expression, throwing IllegalArgumentException if the test result is false.
      static void notEmpty​(java.lang.Object[] array, java.lang.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​(java.lang.Object object)
      Assert that an object is not null .
      static void notNull​(java.lang.Object object, java.lang.String message)
      Assert that an object is not null .
      static void state​(boolean expression, java.lang.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,
                          java.lang.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:
        java.lang.IllegalArgumentException - if expression is false

      • notNull

        public static void notNull​(java.lang.Object object,
                           java.lang.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:
        java.lang.IllegalArgumentException - if the object is null

      • notNull

        public static void notNull​(java.lang.Object object)
        Assert that an object is not null . 
        Assert.notNull(clazz);
        Parameters:
        object - the object to check
        Throws:
        java.lang.IllegalArgumentException - if the object is null

      • hasLength

        public static void hasLength​(java.lang.String text,
                             java.lang.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​(java.lang.Object[] array,
                            java.lang.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:
        java.lang.IllegalArgumentException - if the object array is null or has no elements

      • state

        public static void state​(boolean expression,
                         java.lang.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:
        java.lang.IllegalStateException - if expression is false