設計模式——模板方法模式

模板方法模式就是在父（基）類定義模板（流程），而具體的處理環節交給子類來實現

/**
 * @author maikec
 * @date 2019/5/10
 */
public abstract class AbstractDisplay {
    private final Integer PRINT_COUNT =5;
    /**
     * 打開操作
     */
    protected abstract void open();

    /**
     * 列印操作
     */
    protected abstract void print();

    /**
     * 關閉操作
     */
    protected abstract void close();
     /**
     * 定義模板
     */
    public final void display(){
        open();
        for (int i = 0; i < PRINT_COUNT; i++) {
            print();
        }
        close();
    }
}

/**
 * @author maikec
 * @date 2019/5/10
 */
public class CharDisplay extends AbstractDisplay {
    private final Character aChar;
    public CharDisplay(Character aChar){
        if (null == aChar){
            throw new IllegalArgumentException( "Character cannot be null" );
        }
        this.aChar = aChar;
    }
    @Override
    public void open() {
        System.out.println( "Open Char " );
    }

    @Override
    public void print() {
        System.out.println( aChar.charValue() );
    }

    @Override
    public void close() {
        System.out.println( "Close Char" );
    }
}

/**
 * @author maikec
 * @date 2019/5/10
 */
public class StringDisplay extends AbstractDisplay {
    private final String string ;
    public StringDisplay(String string){
        if (null == string){
            throw new IllegalArgumentException( "String cannot be null" );
        }
        this.string = string;
    }
    @Override
    public void open() {
        System.out.println( "Open String" );
    }

    @Override
    public void print() {
        System.out.println( string );
    }

    @Override
    public void close() {
        System.out.println( "Close String" );
    }
}

/**
 * @author maikec
 * @date 2019/5/10
 */
public class TemplateDemo {
    public static void main(String[] args) {
        AbstractDisplay display = new CharDisplay( '*' );
        display.display();

        AbstractDisplay stringDisplay = new StringDisplay( "Hi" );
        stringDisplay.display();
    }
}

附錄

github.com/maikec/patt… 個人GitHub設計模式案例

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