[DesignPattern - Decorator] sample1

Design Pattern - Decorator

1. 클래스다이어그램

2. Source

• Display.java

  package com.dazzilove.decorator.sample1;
  
  public abstract class Display {
      public abstract int getColumns();
      public abstract int getRows();
      public abstract String getRowText(int row);
      public final void show() {
          for(int i=0; i            System.out.println(getRowText(i));
          }
      }
  }

• StringDisplay.java

  package com.dazzilove.decorator.sample1;
  
  public class StringDisplay extends Display {
      private String string;
      public StringDisplay(String string) {
          this.string = string;
      }
      @Override
      public int getColumns() {
          return string.getBytes().length;
      }
      @Override
      public int getRows() {
          return 1;
      }
      @Override
      public String getRowText(int row) {
          if(row == 0) {
              return string;
          } else {
              return null;
          }
      }
  }

• Border.java

  package com.dazzilove.decorator.sample1;
  
  public abstract class Border extends Display {
      protected Display display;
      protected Border(Display display) {
          this.display = display;
      }
  }

• SideBorder.java

  package com.dazzilove.decorator.sample1;
  
  public class SideBorder extends Border {
      private char borderChar;
      public SideBorder(Display display, char ch) {
          super(display);
          this.borderChar = ch;
      }
  
      @Override
      public int getColumns() {
          return 1 + display.getColumns() + 1;
      }
  
      @Override
      public int getRows() {
          return display.getRows();
      }
  
      @Override
      public String getRowText(int row) {
          return borderChar + display.getRowText(row) + borderChar;
      }
  }

• FullBorder.java

  package com.dazzilove.decorator.sample1;
  
  public class FullBorder extends Border {
      public FullBorder(Display display) {
          super(display);
      }
      @Override
      public int getColumns() {
          return 1 + display.getColumns() + 1; // 문자의 수는 내용물의 양쪽에 좌우의 장식 문자 개수를 더한 것
      }
      @Override
      public int getRows() {
          return 1 + display.getRows() + 1; // 줄 수는 내용물의 줄 수에 상하의 장식문자분을 더한 것
      }
      @Override
      public String getRowText(int row) {
          if(row == 0) {                                                  // 장식의 상단
              return "+" + makeLine('-', display.getColumns()) + "+";
          } else if(row == display.getRows() + 1) {       // 장식의 하단
              return "+" + makeLine('-', display.getColumns()) + "+";
          } else {                                                           // 그밖에
              return "|" + display.getRowText(row - 1) + "|";
          }
      }
      private String makeLine(char ch, int count) {
          StringBuffer sb = new StringBuffer();
          for(int i=0; i            sb.append(ch);
          }
          return sb.toString();
      }
  }

• Main.java

  package com.dazzilove.decorator.sample1;
  
  public class Main {
      public static void main(String[] args) {
          Display display1 = new StringDisplay("Hello, world.");
          display1.show();
          System.out.println("");
          
          Display display2 = new SideBorder(display1, '#');
          display2.show();
          System.out.println("");
          
          Display display3 = new FullBorder(display2);
          display3.show();
          System.out.println("");
          
          Display display4 = new SideBorder(new FullBorder(new FullBorder(new SideBorder(new FullBorder(new StringDisplay("안녕하세요")), '*'))), '/');
          display4.show();
      }
  }

3. 결과출력