org.apache.cayenne.event

Class EventSubject

java.lang.Object

org.apache.cayenne.event.EventSubject

All Implemented Interfaces:

Serializable

public class EventSubject
extends Object
implements Serializable

This class encapsulates the String that is used to identify the subject that a listener is interested in. Using plain Strings causes several severe problems:

• it's easy to misspell a subject, leading to undesired behaviour at runtime that is hard to debug.
• in systems with many different subjects there is no safeguard for defining the same subject twice for different purposes. This is especially true in a distributed setting.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	EventSubject(String fullSubjectName) Protected constructor for new subjects.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
static EventSubject	getSubject(Class<?> subjectOwner, String subjectName) Returns an event subject identified by the given owner and subject name.
String	getSubjectName()
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

EventSubject

protected EventSubject(String fullSubjectName)

Protected constructor for new subjects.

Parameters:

fullSubjectName - the name of the new subject to be created

Method Detail

getSubject

public static EventSubject getSubject(Class<?> subjectOwner,
                      String subjectName)

Returns an event subject identified by the given owner and subject name.

Parameters:

subjectOwner - the Class used for uniquely identifying this subject

subjectName - a String used as name, e.g. "MyEventTopic"

Throws:

IllegalArgumentException - if subjectOwner/subjectName are null or subjectName is empty.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getSubjectName

public String getSubjectName()

toString

public String toString()

Overrides:

toString in class Object

Returns:

a String in the form <ClassName 0x123456> SomeName

See Also:

Object.toString()