需要协助说明特定方法的目的和操作

Question

考试前只看了一些编程问题，我对这个问题感到困惑...

关于附录A中详细介绍的Java类，解释了matchProgrammeCode()方法的目的和操作。 （10）

功能接口– 2个标记，本地等级– 3个标记，操作– 5个标记

附录A学生

 public class Student {
    int studentId;
    String studentName;
    String programmeCode;
    Collection<ModuleRegistration> registeredModules;

    static int noStudents = 0;

    public Student() { … }

    public Student(String studentName, String programmeCode) { … }

    public Student(int studentId, String studentName,
                   String programmeCode) { … }

    public int getStudentId(){ … }

    public String getStudentName(){ … }

    public void setStudentName(String studentName) { … }

    public String getProgrammeCode(){ … }

    public void setProgrammeCode(String programmeCode) { … }

    public void addModule(ModuleRegistration moduleRegistration)
    { … }

    @Override
    public String toString() { … }

    interface CheckStudent { boolean test(Student s); }

    class CheckStudentProgrammeCode implements CheckStudent {
        String programmeCode;

        CheckStudentProgrammeCode(String programmeCode) {
            this.programmeCode = programmeCode;
        }

        @Override
        public boolean test(Employee s) {
            return s.getProgrammeCode().equals(this.programmeCode);
        }
    }

    public boolean matchProgrammeCode(String programmeCode) {
        CheckStudentProgrammeCode tester =
            new CheckStudentProgrammeCode(String programmeCode);
        return tester.test(this);
    }
}

任何帮助将不胜感激，谢谢。

Answer 1

这种方法实际上做无非是比较多programmeCode您的实例的属性Student你给它作为一个参数的字符串。 然后，您可以在主目录中这样使用它：

Student s = Student();
s.setProgrammeCode("Hello World");
if(s.matchProgrammeCode("Hello World")) {
    /* Programmecode is equal :) */
}

很难解释您的代码中发生了什么，因为我不知道您在Java编程方面有多高级，但是我已经编辑了您的代码，以便仅保留问题的相关部分，并添加了一些注释，希望可以解释一下足够好：

public class Student {
    String programmeCode;

    public Student() { … }

    // Everything that implements this interface will assure it has the method "test"
    interface CheckStudent { boolean test(Student s); }

    // Implements CheckStudent, therefore has to have the method "test"
    // Also is an inner class of your Student-class
    class CheckStudentProgrammeCode implements CheckStudent {
        String programmeCode;

        CheckStudentProgrammeCode(String programmeCode) {
            // Constructor safes a string
            this.programmeCode = programmeCode;
        }
        // Concrete implementation of the test-method which is required after implementing the interface
        @Override
        public boolean test(Employee s) {
            // equals compares the programmeCode that was safed by the constructor with the s.getProgrammeCode() of the given object
            // then returns the outcome of the equal method - true if they are equal, false if not
            // It is equivalent to:
            // if(s.getProgrammeCode().equals(this.programmeCode)) {return true;} else {return false;}
            return s.getProgrammeCode().equals(this.programmeCode);
        }
    }

    public boolean matchProgrammeCode(String programmeCode) {
        // Creating a new, local instance of CheckStudentProgrammeCode and passing the
        // String programmeCode directly from the parameter of the method into the instance's constructor
        CheckStudentProgrammeCode tester =
            new CheckStudentProgrammeCode(String programmeCode);
        // The test-method takes the instance of Student itself (this) and returns a boolean, which will then be passed directly into the return of the method
        return tester.test(this);
    }
}