Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.awt.Component;

import java.util.EventListener;

import javax.swing.event.EventListenerList;

public class Main {
    /**
     * Checks if the listener is always registered to the EventListenerList to avoid duplicated registration of the same listener
     *
     * @param list the EventListenerList to register the listener.
     * @param t    the type of the EventListener.
     * @param l    the listener.
     * @return true if already registered. Otherwise false.
     */
    public static boolean isListenerRegistered(EventListenerList list, Class t, EventListener l) {
        Object[] objects = list.getListenerList();

        return isListenerRegistered(objects, t, l);
    }

    /**
     * Checks if the listener is always registered to the Component to avoid duplicated registration of the same listener
     *
     * @param component the component that you want to register the listener.
     * @param t         the type of the EventListener.
     * @param l         the listener.
     * @return true if already registered. Otherwise false.
     */
    public static boolean isListenerRegistered(Component component, Class t, EventListener l) {
        Object[] objects = component.getListeners(t);

        return isListenerRegistered(objects, t, l);
    }

    private static boolean isListenerRegistered(Object[] objects, Class t, EventListener l) {
        for (int i = 0; i < objects.length; i++) {
            Object listener = objects[i];

            if (t.isAssignableFrom(listener.getClass()) && (listener == l)) {
                return true;
            }
        }

        return false;
    }
}