package com.roc.responsibility;

/**

 * 判断是否为空的抽象类

 * @author liaowp

 *

 */

public abstract class IsEmptyAbstract {

    protected IsEmptyAbstract isEmptyAbstract;

    public void setIsEmptyAbstract(IsEmptyAbstract isEmptyAbstract) {

        this.isEmptyAbstract = isEmptyAbstract;

    }

    public boolean  inputMsg(String str){

          if(isEmpty(str)){//

              return true;

          }else{//如果没有判断出来就传入下一个

              if(isEmptyAbstract !=null){

                  return isEmptyAbstract.isEmpty(str);

               }else{

                   System.out.println("判断器没有初始化");

                   return false;

               }

          }

    }

    /**

     * 判断是否为空

     * @return

     */

    abstract protected boolean isEmpty(String str);

}

package com.roc.responsibility;

/**

 * 判断是不是null

 * @author liaowp

 *

 */

public class isNull extends IsEmptyAbstract{

    @Override

    protected boolean isEmpty(String str) {

        return null==str;

    }

}

package com.roc.responsibility;

/**

 * 判断是不是""

 * @author liaowp

 *

 */

public class IsEmpty extends IsEmptyAbstract{

    @Override

    protected boolean isEmpty(String str) {

        return "".equals(str);

    }

}

package com.roc.responsibility;

/**

 * 责任链模式

 * @author liaowp

 *

 */

public class Client {

    public static void main(String[] args) {

        String str = "";

        isNull isNull = new isNull();

        IsEmpty isEmpty = new IsEmpty();

        isNull.setIsEmptyAbstract(isEmpty);

        System.out.println(isNull.inputMsg(str));

    }

}