자바

[자바] builder 패턴

devjones 2021. 6. 3. 14:46 
package builder;

public abstract class Builder {
	public abstract void makeTitle(String title);
	public abstract void makeString(String str);
	public abstract void makeItems(String[] items);
	public abstract void close();
}

package builder;

public class Director {

	private Builder builder;
	
	public Director(Builder builder) {
		this.builder = builder;
	}
	
	public void construct() {
		builder.makeTitle("Greeting");
		builder.makeString("아침과 낮에");
		builder.makeItems(new String[] {
				"좋은 아침입니다.",
				"안녕하세요."
		});
		
		builder.makeString("밤에");
		builder.makeItems(new String[] {
				"안녕하세요",
				"안녕히 주무세요",
				"안녕히 계세요."
		});
		
		builder.close();
	}
}

package builder;

public class TextBuilder extends Builder {
	private StringBuffer buffer = new StringBuffer();
	
	@Override
	public void makeTitle(String title) {
		buffer.append("===============================\n");
		buffer.append("『" + title + "』\n");
		buffer.append("\n");
	}
	
	@Override
	public void makeString(String str) {
		buffer.append("■" + str + "\n");
		buffer.append("\n");
	}
	
	@Override
	public void makeItems(String[] items) {
		for (int i = 0; i < items.length; i++) {
			buffer.append("●" + items[i] + "\n");
		}
		buffer.append("\n");
	}
	
	@Override
	public void close() {
		buffer.append("===============================\n");
	}
	
	public String getResult() {
		return buffer.toString();
	}
}

package builder;

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class HTMLBuilder extends Builder {
	private String fileName;
	
	private PrintWriter writer;
	
	@Override
	public void makeTitle(String title) {
		fileName = title + ".html";
		
		try {
			writer = new PrintWriter(new FileWriter(fileName));
			
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		writer.println("<html><head><title>" + title + "</title></head><body>");
		writer.println("<h1>" + title + "</h1>");
	}
	
	@Override
	public void makeString(String str) {
		writer.println("<p>" + str + "</p>");
	}
	
	@Override
	public void makeItems(String[] items) {
		writer.println("<ul>");
		for (int i = 0; i < items.length; i++) {
			writer.println("<li>" + items[i] + "</li>");
		}
		writer.println("</ul>");
	}
	
	@Override
	public void close() {
		writer.println("</body></html>");
		writer.close();
	}
	
	public String getResult() {
		return fileName;
	}
}

package builder;

public class Main {
	public static void main(String[] args) {
		if(args.length != 1) {
			usage();
			System.exit(0);
		}
		if(args[0].equals("plain")) {
			TextBuilder textBuilder = new TextBuilder();
			Director director = new Director(textBuilder);
			director.construct();
			String result = textBuilder.getResult();
			System.out.println(result);
		}else if(args[0].equals("html")) {
			HTMLBuilder htmlBuilder = new HTMLBuilder();
			Director director = new Director(htmlBuilder);
			director.construct();
			String fileName = htmlBuilder.getResult();
			System.out.println(fileName + "가 작성되었습니다.");
		}else {
			usage();
			System.exit(0);
		}
	}
	public static void usage() {
		System.out.println("NO parameter");
	}
}

 

결과:

 

 

빌더패턴 정리

Builder(건축자)의 역할