patterntesting.runtime.junit

Class ObjectTester

java.lang.Object

patterntesting.runtime.junit.AbstractTester

patterntesting.runtime.junit.ObjectTester

public final class ObjectTester
extends AbstractTester

This is a utility class to check some important methods of a class like the Object.equals(Object) or Object.hashCode() method. Before v1.1 the methods are named "checkEquals" or "checkCompareTo". Since 1.1 these methods have now an "assert" prefix ("assertEquals" or "assertCompareTo").

Since:

1.0.3 (21.07.2010)

Author:

oliver

Method Summary

Modifier and Type	Method and Description
static <T> void	assertAll(Class<? extends T> clazz) Starts all known checks like checkEquals(..), checks from the SerializableTester (if the given class is serializable) or from other classes.
static <T> void	assertAll(Collection<Class<? extends T>> classes) Check all.
static void	assertAll(Package pkg) Starts all known checks for all classes of the given package.
static void	assertAll(Package pkg, Class<?>... excluded) Starts all known checks for all classes of the given package except for the "excluded" classes.
static void	assertAllOfPackage(String packageName) Starts all known checks for all classes of the given package.
static void	assertAllOfPackage(String packageName, Class<?>... excluded) Starts all known checks for all classes of the given package but not for the "excluded" classes.
static void	assertAllOfPackage(String packageName, Pattern... excluded) Starts all known checks for all classes of the given package but not for the "excluded" classes.
static void	assertCompareTo(Object o1, Object o2) Check equality of the given objects by using the compareTo() method.
static void	assertEquals(Class<?> clazz) This method will create two objects of the given class using the default constructor.
static void	assertEquals(Cloneable obj) The given object will be cloned to get a copy of that object.
static <T> void	assertEquals(Collection<Class<? extends T>> classes) Check for each class in the given collection if the equals() method is implemented correct.
static void	assertEquals(Object o1, Object o2) Check equality of the given objects.
static void	assertEquals(Package pkg) Check for each class in the given package if the equals() method is implemented correct.
static void	assertEquals(Package pkg, Class<?>... excluded) Check for each class in the given package if the equals() method is implemented correct.
static void	assertEquals(Package pkg, Pattern... excluded) Check for each class in the given package if the equals() method is implemented correct.
static void	assertEquals(Serializable obj) The given object will be serialized and deserialized to get a copy of that object.
static void	assertEqualsOfPackage(String packageName) Check for each class in the given package if the equals() method is implemented correct.
static void	assertEqualsOfPackage(String packageName, Class<?>... excluded) Check for each class in the given package if the equals() method is implemented correct.
static void	assertEqualsOfPackage(String packageName, Pattern... excluded) Check for each class in the given package if the equals() method is implemented correct.
static void	assertNotEquals(Object a, Object b) Checks if the two given objects are really not equals.
static void	assertToString(Object obj) If a object is only partially initalized it sometimes can happen, that calling the toString() method will result in a NullPointerException.
static boolean	hasEqualsDeclared(Class<?> clazz) If you want to know if a class (or one of its super classes, except object) has overwritten the equals method you can use this method here.
static boolean	hasToStringDefaultImpl(Class<?> clazz) Normally you should overwrite the toString() method for better logging and debugging.
static boolean	hasToStringDefaultImpl(Object obj) Normally you should overwrite the toString() method for better logging and debugging.

Methods inherited from class patterntesting.runtime.junit.AbstractTester

removeClasses, removeClasses

Methods inherited from class java.lang.Object

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

Method Detail

assertEquals

public static void assertEquals(Object o1,
                                Object o2)
                         throws AssertionError

Check equality of the given objects. They must be equals otherwise an AssertionError will be thrown. And if A == B also B == A must be true (commutative law, i.e. it is a symmetrical operation).

If two objects are equals they must have also the same hash code (but not the other way around). This condition is also checked here.

Often programmers forget that the Object.equals(Object) method can be called with null as argument and should return false as result. So this case is also tested here.

Parameters:

o1 - the 1st object

o2 - the 2nd object

Throws:

AssertionError - if the check fails

Since:

1.1

assertNotEquals

public static void assertNotEquals(Object a,
                                   Object b)
                            throws AssertionError

Checks if the two given objects are really not equals. The following conditions should be fullfilled: if (a != b) then also (b != a) should be true. This is tested here.

Parameters:

a - the a

b - the b

Throws:

AssertionError - the assertion error

Since:

1.5

assertEquals

public static void assertEquals(Serializable obj)
                         throws NotSerializableException

The given object will be serialized and deserialized to get a copy of that object. The copy must be equals to the original object.

If the check fails (e.g. if copy and original object are not equals) an AssertionError will be thrown.

Parameters:

obj - the object

Throws:

NotSerializableException - if obj is not serializable

Since:

1.1

assertEquals

public static void assertEquals(Cloneable obj)
                         throws AssertionError

The given object will be cloned to get a copy of that object. The copy must be equals to the original object.

Parameters:

obj - the obj

Throws:

AssertionError - the assertion error

Since:

1.1

assertEquals

public static void assertEquals(Class<?> clazz)
                         throws AssertionError

This method will create two objects of the given class using the default constructor. So three preconditions must be true:

1. the class must not be abstract
2. there must be a (public) default constructor
3. it must be Cloneable, Serializable or return always the same object

That a constructor creates equals objects is not true for all classes. For example the default constructor of the Date class will generate objects with different timestamps which are not equal. But most classes should meet the precondition.

Parameters:

clazz - the clazz

Throws:

AssertionError - if the check fails

Since:

1.1

assertEquals

public static <T> void assertEquals(Collection<Class<? extends T>> classes)
                             throws Failures

Check for each class in the given collection if the equals() method is implemented correct.

Type Parameters:

T - the generic type

Parameters:

classes - the classes

Throws:

Failures - the collected assertion errors

Since:

1.1

assertEquals

public static void assertEquals(Package pkg)

Check for each class in the given package if the equals() method is implemented correct.

To get a name of a package call Package.getPackage(String). But be sure that you can't get null as result. In this case use assertEqualsOfPackage(String).

Parameters:

pkg - the package e.g. "patterntesting.runtime"

Since:

1.1

See Also:

assertEqualsOfPackage(String)

assertEquals

public static void assertEquals(Package pkg,
                                Class<?>... excluded)

Check for each class in the given package if the equals() method is implemented correct.

To get a name of a package call Package.getPackage(String). But be sure that you can't get null as result. In this case use assertEqualsOfPackage(String, Class...).

Parameters:

pkg - the package e.g. "patterntesting.runtime"

excluded - classes which are excluded from the check

Since:

1.1

See Also:

assertEqualsOfPackage(String, Class...)

assertEquals

public static void assertEquals(Package pkg,
                                Pattern... excluded)

Check for each class in the given package if the equals() method is implemented correct. E.g. if your unit test classes ends all with "...Test" and you want to remove them from the check you can call

 ObjectTester.assertEquals(pkg, Pattern.compile(".*Test"));
 

Parameters:

pkg - the package

excluded - class pattern which should be excluded from the check

Since:

1.6

assertEqualsOfPackage

public static void assertEqualsOfPackage(String packageName)

Check for each class in the given package if the equals() method is implemented correct.

This method does the same as assertEquals(Package) but was introduced by Package.getPackage(String) sometimes return null if no class of this package is loaded.

Parameters:

packageName - the package name e.g. "patterntesting.runtime"

Since:

1.1

See Also:

assertEquals(Package)

assertEqualsOfPackage

public static void assertEqualsOfPackage(String packageName,
                                         Class<?>... excluded)

Check for each class in the given package if the equals() method is implemented correct.

Parameters:

packageName - the package name e.g. "patterntesting.runtime"

excluded - classes which should be excluded from the check

Since:

1.1

See Also:

assertEqualsOfPackage(String)

assertEqualsOfPackage

public static void assertEqualsOfPackage(String packageName,
                                         Pattern... excluded)

Check for each class in the given package if the equals() method is implemented correct. E.g. if your unit test classes ends all with "...Test" and you want to remove them from the check you can call

 ObjectTester.assertEqualsOfPackage("my.package", Pattern.compile(".*Test"));
 

Parameters:

packageName - the package name e.g. "patterntesting.runtime"

excluded - class pattern which should be excluded from the check

Since:

1.6

hasEqualsDeclared

public static boolean hasEqualsDeclared(Class<?> clazz)

If you want to know if a class (or one of its super classes, except object) has overwritten the equals method you can use this method here.

Parameters:

clazz - the clazz

Returns:

true, if successful

assertCompareTo

public static void assertCompareTo(Object o1,
                                   Object o2)
                            throws AssertionError

Check equality of the given objects by using the compareTo() method. Because casting an object to the expected Comparable is awesome we provide this additional method here

Parameters:

o1 - the first object (must be of type Comparable)

o2 - the second object (must be of type Comparable)

Throws:

AssertionError - if the check fails

Since:

1.1

See Also:

ComparableTester.assertCompareTo(Comparable, Comparable)

assertToString

public static void assertToString(Object obj)

If a object is only partially initalized it sometimes can happen, that calling the toString() method will result in a NullPointerException. This should not happen so there are several check methods available where you can proof it.

Parameters:

obj - the object to be checked

Since:

1.1

hasToStringDefaultImpl

public static boolean hasToStringDefaultImpl(Object obj)

Normally you should overwrite the toString() method for better logging and debugging. This is the method to check it.

Parameters:

obj - the object to be checked

Returns:

true, if object has default implementation

hasToStringDefaultImpl

public static boolean hasToStringDefaultImpl(Class<?> clazz)

Normally you should overwrite the toString() method for better logging and debugging. This is the method to check it.

Parameters:

clazz - the clazz

Returns:

true, if object has default implementation

assertAll

public static <T> void assertAll(Class<? extends T> clazz)

Starts all known checks like checkEquals(..), checks from the SerializableTester (if the given class is serializable) or from other classes.

Type Parameters:

T - the generic type

Parameters:

clazz - the clazz to be checked.

Since:

1.1

assertAll

public static <T> void assertAll(Collection<Class<? extends T>> classes)

Check all.

Type Parameters:

T - the generic type

Parameters:

classes - the classes to be checked

Since:

1.1

assertAll

public static void assertAll(Package pkg)

Starts all known checks for all classes of the given package.

To get a name of a package call Package.getPackage(String). But be sure that you can't get null as result. In this case use assertAllOfPackage(String).

Parameters:

pkg - the package e.g. "patterntesting.runtime"

Since:

1.1

assertAll

public static void assertAll(Package pkg,
                             Class<?>... excluded)

Starts all known checks for all classes of the given package except for the "excluded" classes.

To get a name of a package call Package.getPackage(String). But be sure that you can't get null as result. In this case use assertEqualsOfPackage(String, Class...).

Parameters:

pkg - the package e.g. "patterntesting.runtime"

excluded - classes which are excluded from the check

Since:

1.1

See Also:

assertAllOfPackage(String, Class...)

assertAllOfPackage

public static void assertAllOfPackage(String packageName)

Starts all known checks for all classes of the given package.

Parameters:

packageName - the package e.g. "patterntesting.runtime"

Since:

1.1

assertAllOfPackage

public static void assertAllOfPackage(String packageName,
                                      Class<?>... excluded)

Starts all known checks for all classes of the given package but not for the "excluded" classes.

Parameters:

packageName - the package name e.g. "patterntesting.runtime"

excluded - classes which should be excluded from the check

Since:

1.1

See Also:

assertAllOfPackage(String)

assertAllOfPackage

public static void assertAllOfPackage(String packageName,
                                      Pattern... excluded)

Starts all known checks for all classes of the given package but not for the "excluded" classes. E.g. if your unit test classes ends all with "...Test" and you want to remove them from the check you can call

 ObjectTester.assertEqualsOfPackage("my.package", Pattern.compile(".*Test"));
 

Parameters:

packageName - the package name e.g. "patterntesting.runtime"

excluded - class pattern which should be excluded from the check

Since:

1.6