Package spark.utils
Class Assert
- java.lang.Object
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- spark.utils.Assert
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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).
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Constructor Summary
Constructors Constructor Description Assert()
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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 benull
and not the empty String.static void
isTrue(boolean expression, java.lang.String message)
Assert a boolean expression, throwingIllegalArgumentException
if the test result isfalse
.static void
notEmpty(java.lang.Object[] array, java.lang.String message)
Assert that an array has elements; that is, it must not benull
and must have at least one element.static void
notNull(java.lang.Object object)
Assert that an object is notnull
.static void
notNull(java.lang.Object object, java.lang.String message)
Assert that an object is notnull
.static void
state(boolean expression, java.lang.String message)
Assert a boolean expression, throwingIllegalStateException
if the test result isfalse
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Method Detail
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isTrue
public static void isTrue(boolean expression, java.lang.String message)
Assert a boolean expression, throwingIllegalArgumentException
if the test result isfalse
.Assert.isTrue(i > 0, "The value must be greater than zero");
- Parameters:
expression
- a boolean expressionmessage
- the exception message to use if the assertion fails- Throws:
java.lang.IllegalArgumentException
- if expression isfalse
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notNull
public static void notNull(java.lang.Object object, java.lang.String message)
Assert that an object is notnull
.Assert.notNull(clazz, "The class must not be null");
- Parameters:
object
- the object to checkmessage
- the exception message to use if the assertion fails- Throws:
java.lang.IllegalArgumentException
- if the object isnull
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notNull
public static void notNull(java.lang.Object object)
Assert that an object is notnull
.Assert.notNull(clazz);
- Parameters:
object
- the object to check- Throws:
java.lang.IllegalArgumentException
- if the object isnull
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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 benull
and not the empty String.Assert.hasLength(name, "Name must not be empty");
- Parameters:
text
- the String to checkmessage
- the exception message to use if the assertion fails- See Also:
StringUtils.hasLength(java.lang.CharSequence)
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notEmpty
public static void notEmpty(java.lang.Object[] array, java.lang.String message)
Assert that an array has elements; that is, it must not benull
and must have at least one element.Assert.notEmpty(array, "The array must have elements");
- Parameters:
array
- the array to checkmessage
- the exception message to use if the assertion fails- Throws:
java.lang.IllegalArgumentException
- if the object array isnull
or has no elements
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state
public static void state(boolean expression, java.lang.String message)
Assert a boolean expression, throwingIllegalStateException
if the test result isfalse
. 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 expressionmessage
- the exception message to use if the assertion fails- Throws:
java.lang.IllegalStateException
- if expression isfalse
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