Structure Array Structure Array:軽量レベルのアレイ

紹介する

は、頻繁に変化する属性(または外在的属性)と不変の属性(または内在的属性)を分離して再利用することができ、メモリの使用を減らすことができる.

1)メリット

2）欠点

適用前

public class Client {
	public static void main(String[] args) {
    	Character c1 = new Character('h', "white", "Nanum", 12);
        Character c2 = new Character('e', "white", "Nanum", 12);
        Character c3 = new Character('l', "white", "Nanum", 12);
        Character c4 = new Character('l', "white", "Nanum", 12);
        Character c5 = new Character('o', "white", "Nanum", 12);
    }
}

インプリメンテーション

1）工場の作成

public class FontFactory {
	
    private Map<String, Font> cache = new HashMap<>();
    
    public Font getFont(String font) {
    	if(cache.containsKey(font)) {
        	return cache.get(font);
        } else {
        	String[] splist = font.split(":");
            Font newFont = new Font(split[0], Integer.parseInt(split[1]));
            cache.put(font, newFont);
            return newFont;
        }
    }
}

2)内部要素の定義

public final class Font {
	final String family;
    final int size;
    
    public Font(String family, int size) {
    	this.family = family;
       	this.size = size;
    }
    
    public String getFamily(){
    	return family;
    }
    
    public int getSize() {
    	return size;
    }
}

3)外部要素の定義

public class Character {

	private char value;
    private String color;
    private Font font;
    
    public Character(char value, String color, Font font) {
		this.value = value;
        this.color = color;
        this.font = font;
	}
}

使用

public class Client {
	public static void main(String[] args) {
    	FontFactory fontFactory = new FontFactory();
        Character c1 = new Character('h', "white", fontFactory.getFont("nanum:12");
        Character c2 = new Character('e', "white", fontFactory.getFont("nanum:12");
        Character c3 = new Character('l', "white", fontFactory.getFont("nanum:12");
        Character c4 = new Character('l', "white", fontFactory.getFont("nanum:12");
        Character c5 = new Character('o', "white", fontFactory.getFont("nanum:12");
    }
}