Package org.xjge.core

Class Observable

java.lang.Object
org.xjge.core.Observable
public class Observable
extends java.lang.Object
A Component object which can be used to relay information about state changes occurring in the implementing object to one or more observers located anywhere in the codebase.

Objects which make use of observable should define the properties (often fields) observers should look for in their constructors with the properties collection provided. This usually looks something like this: 

 int prop1     = 0;
 boolean prop2 = false;
 char prop3    = 'someVal';
 
 Observable observable = new Observable(this);
 
 MyObject(Object other) {
     ...
     observable.properties.put("myProperty1", prop1);
     observable.properties.put("myProperty2", prop2);
     observable.properties.put("myProperty3", prop3);
     ...
     observable.addObserver(other);
     ...
 }
 
 //Called every game tick...
 MyObject.update() {
     notifyObservers("myProperty1", prop1);
     notifyObservers("myProperty2", prop2);
     notifyObservers("myProperty3", prop3);
     ...
 }
Since:
2.0.0

  • Field Summary

    Fields
    Modifier and Type Field Description
    java.util.HashMap<java.lang.String,​java.lang.Object> properties  

  • Constructor Summary

    Constructors
    Constructor Description
    Observable​(java.lang.Object object)
    Creates a new observable object that will look for state changes in the object provided and supply it to other parts of the codebase.

  • Method Summary

    Modifier and Type Method Description
    void addObserver​(java.beans.PropertyChangeListener observer)
    Exposes this objects state to another.
    void notifyObservers​(java.lang.String name, java.lang.Object property)
    Notifies all observers of state changes in this object.
    void removeObserver​(java.beans.PropertyChangeListener observer)
    Revokes an observers access to view the state changes of implementing objects.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • properties

      public final java.util.HashMap<java.lang.String,​java.lang.Object> properties

  • Constructor Details

    • Observable

      public Observable​(java.lang.Object object)
      Creates a new observable object that will look for state changes in the object provided and supply it to other parts of the codebase.
      Parameters:
      object - the implementing object that will expose its state

  • Method Details

    • addObserver

      public void addObserver​(java.beans.PropertyChangeListener observer)
      Exposes this objects state to another. Observer objects must implement PropertyChangeListener.
      Parameters:
      observer - the object that is interested in the state changes of the one implementing the Observable component

    • removeObserver

      public void removeObserver​(java.beans.PropertyChangeListener observer)
      Revokes an observers access to view the state changes of implementing objects.
      Parameters:
      observer - the observer to remove

    • notifyObservers

      public void notifyObservers​(java.lang.String name, java.lang.Object property)
      Notifies all observers of state changes in this object.
      Parameters:
      name - the name of the property (field) we're observing
      property - an object representing the value of the property changed