Returns all elements of a specific class from a container. - Java java.awt

Java examples for java.awt:Container

  1. HOME
  2. Java
  3. java.awt
  4. Container

Description

Returns all elements of a specific class from a container.

Demo Code


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

import java.util.ArrayList;

import java.util.List;

public class Main {
    /**/*from  w  w  w .j av a  2  s  .c o m*/
     * Returns all elements of a specific class from a container.
     *
     * <em>Only elements of that class are detected, not sub- and supertyes!</em>
     *
     * @param <T> class type
     * @param container container
     * @param clazz class
     * @return found elements or empty list
     */
    public static <T> List<T> getAllOf(Container container, Class<T> clazz) {
        if (container == null) {
            throw new NullPointerException("container == null");
        }

        if (clazz == null) {
            throw new NullPointerException("clazz == null");
        }

        List<T> components = new ArrayList<>();

        addAllOf(container, clazz, components);

        return components;
    }

    @SuppressWarnings("unchecked")
    private static <T> void addAllOf(Container container, Class<T> clazz,
            List<T> all) {
        int count = container.getComponentCount();

        if (container.getClass().equals(clazz)) {
            all.add((T) container);
        }

        for (int i = 0; i < count; i++) {
            Component component = container.getComponent(i);

            if (component instanceof Container) {
                addAllOf((Container) component, clazz, all); // Recursive
            } else if (component.getClass().equals(clazz)) {
                all.add((T) component);
            }
        }
    }
}

Related Tutorials