//------------------------------------------------------------------------------
// Creating and Consuming a Custom Event
//------------------------------------------------------------------------------
//
// In this example we have a class (SomeEntryList) that we want to raise events 
// when an item is added so that the consumer will know that it happened and 
// handle it/them accordingly.
//
//------------------------------------------------------------------------------



/*
*=================================================================================
*
* IMPLEMENTING A CONSUMER OF THE EVENT
*
*=================================================================================
*/

SomeEntryList sel = new SomeEntryList();

// Register to receive EntryAddedEvents
sel.addEntryAddedEventListener(new EntryAddedEventListener() {
    @Override
    public void OnEntryAdded(EntryAddedEvent evt) {
        // This is where we have our event handler logic
        String s = evt.getEntryText();
        int i = evt.getNumInList();
        DosSomethingWithSandI(s, i);
    }
});

sel.AddEntries(200);



/*
*=================================================================================
*
* CREATING SomeEntryList CLASS --- EXPOSING THE OnEntryAdded Event
*
*=================================================================================
*/
public class SomeEntryList {

    /*
    * -------------------------------------------------------------------------
    * This is where our class does something and raises our event -------------
    * -------------------------------------------------------------------------
    */

    private java.util.ArrayList<String> _entryList = new java.util.ArrayList<>();

    public void AddEntries(int numToAdd)
	{
        String s;
        EntryAddedEvent eae;

        for (int i=1; i<=numToAdd; i++)
        {
            s = "Entry" + i.toString();
            _entryList.add(s);

            /* 
            * Here is where we're raising the event
            */
            eae = new EntryAddedEvent(this, s, entryList.size()); 
            this.fireOnEntryAddedEvent(eae);
        }
    }


    /*
    *=================================================================================
    *
    * THIS IS WHERE WE CREATE THE EVENT
    *
    *=================================================================================
    */

    /*
    * -------------------------------------------------------------------------
    * Create The Entry Added Event --------------------------------------------
    * -------------------------------------------------------------------------
    */

    /* Declare the event (must extend EventObject) */
    public class EntryAddedEvent extends java.util.EventObject {

        /*
        * Properties --- 
        * These are available for use in the event handler
        */
        private String _entryText = "";
        public String getEntryText()
        {
            return _entryText;
        }
        
        private int _numInList = 0;
        public int getNumInList()
        {
            return _numInList;
        }
        
        /*
        * Constructor --- 
        * "Object source" parameter and super(source) call are required
        */
        public EntryAddedEvent(Object source, String entryText, int numInList) {
            super(source);
            _entryText = entryText;
            _numInList = numInList;
        }
        
    }        

    /* 
    * Declare the listener interface (must extend EventListener)  
    */
    public interface EntryAddedEventListener extends java.util.EventListener {
        public void OnEntryAdded(EntryAddedEvent evt);
    }

    /* 
    * Create the event listener list and the methods to register/unregister listeners
    */
    protected javax.swing.event.EventListenerList onEntryAddedListenerList =
        new javax.swing.event.EventListenerList();

    public void addEntryAddedEventListener(EntryAddedEventListener listener) {
        onEntryAddedListenerList.add(EntryAddedEventListener.class, listener);
    }
    
    public void removeEntryAddedEventListener(EntryAddedEventListener listener) {
        onEntryAddedListenerList.remove(EntryAddedEventListener.class, listener);
    }    

	
    /*
    * This private method is used to fire OnEntryAdded events
    */
    void fireOnEntryAddedEvent(EntryAddedEvent evt) {
        Object[] listeners = onEntryAddedListenerList.getListenerList();
        for (int i=0; i<listeners.length; i+=2) {
            if (listeners[i]==EntryAddedEventListener.class) {
                ((EntryAddedEventListener)listeners[i+1]).OnEntryAdded(evt);
            }
        }
    }
    
    /*
    * -------------------------------------------------------------------------
    * END: Entry Added Event --------------------------------------------------
    * -------------------------------------------------------------------------
    */

}