Class ListenerMethod

java.lang.Object
  com.vaadin.event.ListenerMethod

All Implemented Interfaces:

Serializable, EventListener

public class ListenerMethod
extends Object
implements EventListener, Serializable

One registered event listener. This class contains the listener object reference, listened event type, the trigger method to call when the event fires, and the optional argument list to pass to the method and the index of the argument to replace with the event object.

This Class provides several constructors that allow omission of the optional arguments, and giving the listener method directly, or having the constructor to reflect it using merely the name of the method.

It should be pointed out that the method receiveEvent(EventObject event) is the one that filters out the events that do not match with the given event type and thus do not result in calling of the trigger method.

Since:

3.0

Version:

6.8.18

Author:

Vaadin Ltd.

See Also:

Serialized Form

Nested Class Summary
class	ListenerMethod.MethodException           Exception that wraps an exception thrown by an invoked method.

 

Constructor Summary
ListenerMethod(Class<?> eventType, Object target, Method method)            Constructs a new event listener from a trigger method.
ListenerMethod(Class<?> eventType, Object target, Method method, Object[] arguments)            Constructs a new event listener from the trigger method and it's arguments.
ListenerMethod(Class<?> eventType, Object target, Method method, Object[] arguments, int eventArgumentIndex)            Constructs a new event listener from a trigger method, it's arguments and the argument index specifying which one is replaced with the event object when the trigger method is called.
ListenerMethod(Class<?> eventType, Object target, String methodName)            Constructs a new event listener from a trigger method name.
ListenerMethod(Class<?> eventType, Object target, String methodName, Object[] arguments)            Constructs a new event listener from a trigger method name and it's arguments.
ListenerMethod(Class<?> eventType, Object target, String methodName, Object[] arguments, int eventArgumentIndex)            Constructs a new event listener from a trigger method name, it's arguments and the argument index specifying which one is replaced with the event object.

 

Method Summary
boolean	equals(Object obj)
Object	getTarget()           Returns the target object which contains the trigger method.
int	hashCode()
boolean	isOrExtendsType(Class<?> eventType)           Compares the type of this ListenerMethod to the given type
boolean	isType(Class<?> eventType)           Compares the type of this ListenerMethod to the given type
boolean	matches(Class<?> eventType, Object target)           Checks if the given object and event match with the ones stored in this listener.
boolean	matches(Class<?> eventType, Object target, Method method)           Checks if the given object, event and method match with the ones stored in this listener.
void	receiveEvent(EventObject event)           Receives one event from the EventRouter and calls the trigger method if it matches with the criteria defined for the listener.

 

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      Method method,
                      Object[] arguments,
                      int eventArgumentIndex)
               throws IllegalArgumentException

Constructs a new event listener from a trigger method, it's arguments and the argument index specifying which one is replaced with the event object when the trigger method is called.

This constructor gets the trigger method as a parameter so it does not need to reflect to find it out.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method

method - the trigger method

arguments - the arguments to be passed to the trigger method

eventArgumentIndex - An index to the argument list. This index points out the argument that is replaced with the event object before the argument set is passed to the trigger method. If the eventArgumentIndex is negative, the triggering event object will not be passed to the trigger method, though it is still called.

Throws:

IllegalArgumentException - if method is not a member of target .

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      String methodName,
                      Object[] arguments,
                      int eventArgumentIndex)
               throws IllegalArgumentException

Constructs a new event listener from a trigger method name, it's arguments and the argument index specifying which one is replaced with the event object. The actual trigger method is reflected from object, and java.lang.IllegalArgumentException is thrown unless exactly one match is found.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method.

methodName - the name of the trigger method. If the object does not contain the method or it contains more than one matching methods java.lang.IllegalArgumentException is thrown.

arguments - the arguments to be passed to the trigger method.

eventArgumentIndex - An index to the argument list. This index points out the argument that is replaced with the event object before the argument set is passed to the trigger method. If the eventArgumentIndex is negative, the triggering event object will not be passed to the trigger method, though it is still called.

Throws:

IllegalArgumentException - unless exactly one match methodName is found in target.

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      Method method,
                      Object[] arguments)
               throws IllegalArgumentException

Constructs a new event listener from the trigger method and it's arguments. Since the the index to the replaced parameter is not specified the event triggering this listener will not be passed to the trigger method.

This constructor gets the trigger method as a parameter so it does not need to reflect to find it out.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method.

method - the trigger method.

arguments - the arguments to be passed to the trigger method.

Throws:

IllegalArgumentException - if method is not a member of target .

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      String methodName,
                      Object[] arguments)
               throws IllegalArgumentException

Constructs a new event listener from a trigger method name and it's arguments. Since the the index to the replaced parameter is not specified the event triggering this listener will not be passed to the trigger method.

The actual trigger method is reflected from target, and java.lang.IllegalArgumentException is thrown unless exactly one match is found.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method.

methodName - the name of the trigger method. If the object does not contain the method or it contains more than one matching methods java.lang.IllegalArgumentException is thrown.

arguments - the arguments to be passed to the trigger method.

Throws:

IllegalArgumentException - unless exactly one match methodName is found in object.

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      Method method)
               throws IllegalArgumentException

Constructs a new event listener from a trigger method. Since the argument list is unspecified no parameters are passed to the trigger method when the listener is triggered.

This constructor gets the trigger method as a parameter so it does not need to reflect to find it out.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method.

method - the trigger method.

Throws:

IllegalArgumentException - if method is not a member of object .

ListenerMethod

public ListenerMethod(Class<?> eventType,
                      Object target,
                      String methodName)
               throws IllegalArgumentException

Constructs a new event listener from a trigger method name. Since the argument list is unspecified no parameters are passed to the trigger method when the listener is triggered.

The actual trigger method is reflected from object, and java.lang.IllegalArgumentException is thrown unless exactly one match is found.

Parameters:

eventType - the event type that is listener listens to. All events of this kind (or its subclasses) result in calling the trigger method.

target - the object instance that contains the trigger method.

methodName - the name of the trigger method. If the object does not contain the method or it contains more than one matching methods java.lang.IllegalArgumentException is thrown.

Throws:

IllegalArgumentException - unless exactly one match methodName is found in target.

Method Detail

receiveEvent

public void receiveEvent(EventObject event)

Receives one event from the EventRouter and calls the trigger method if it matches with the criteria defined for the listener. Only the events of the same or subclass of the specified event class result in the trigger method to be called.

Parameters:

event - the fired event. Unless the trigger method's argument list and the index to the to be replaced argument is specified, this event will not be passed to the trigger method.

matches

public boolean matches(Class<?> eventType,
                       Object target)

Checks if the given object and event match with the ones stored in this listener.

Parameters:

target - the object to be matched against the object stored by this listener.

eventType - the type to be tested for equality against the type stored by this listener.

Returns:

true if target is the same object as the one stored in this object and eventType equals the event type stored in this object. *

matches

public boolean matches(Class<?> eventType,
                       Object target,
                       Method method)

Checks if the given object, event and method match with the ones stored in this listener.

Parameters:

target - the object to be matched against the object stored by this listener.

eventType - the type to be tested for equality against the type stored by this listener.

method - the method to be tested for equality against the method stored by this listener.

Returns:

true if target is the same object as the one stored in this object, eventType equals with the event type stored in this object and method equals with the method stored in this object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

isType

public boolean isType(Class<?> eventType)

Compares the type of this ListenerMethod to the given type

Parameters:

eventType - The type to compare with

Returns:

true if this type of this ListenerMethod matches the given type, false otherwise

isOrExtendsType

public boolean isOrExtendsType(Class<?> eventType)

Compares the type of this ListenerMethod to the given type

Parameters:

eventType - The type to compare with

Returns:

true if this event type can be assigned to the given type, false otherwise

getTarget

public Object getTarget()

Returns the target object which contains the trigger method.

Returns:

The target object