agent.java

Java P2P技术内幕：《Java P2P技术内幕》源码

package server;

import java.util.*;
import java.io.*;


/**
 * The agent object that encapsulates a series of questions and answers.
 */
public class Agent {
    private List problems = new Vector();
    private int totalAnswersCorrect;
    private int totalQuestions;
    private String lastAnswer;

    public Agent() {
        initProblems();
        this.totalQuestions = problems.size();
    }

    /**
 * Loads the questions and answers.
 */
    private void initProblems() {
        Problem problem = null;
        problem = new Problem(1, "Who is the first president?", 
                              "George Washington");
        problems.add(problem);
        problem = new Problem(2, "Who is the second  president?", "John Adams");
        problems.add(problem);
        problem = new Problem(3, "Who is the third president?", 
                              "Thomas Jefferson");
        problems.add(problem);
        problem = new Problem(4, "Who is the fourth president?", 
                              "James Madison");
        problems.add(problem);
        problem = new Problem(5, "Who is the fifth president?", "James Monroe");
        problems.add(problem);
        problem = new Problem(6, "Who is the sixth president?", 
                              "John Quincy Adams");
        problems.add(problem);
        problem = new Problem(7, "Who is the seventh president?", 
                              "Andrew Jackson");
        problems.add(problem);
        problem = new Problem(8, "Who is the eight president?", 
                              "Martin Van Buren");
        problems.add(problem);
        problem = new Problem(9, "Who is the ninth president?", 
                              "William Henry Harrison");
        problems.add(problem);
        problem = new Problem(10, "Who is the tenth president?", "John Tyler");
        problems.add(problem);
    }

    /**
 * Gets the total number of questions
 */
    public int getTotalNumberOfQuestions() {
        return this.totalQuestions;
    }

    /**
 * Returns the next problem.
 */
    public Problem getNextProblem() {
        return (Problem) problems.get(0);
    }

    /**
 * Processes the answer to the current problem.
 *
 * @returns true if answered correctly.
 * @returns false if answered incorrectly.
 */
    public boolean processAnswer(String answer) {
        Problem problem = (Problem) problems.remove(0);
        this.lastAnswer = problem.getAnswer();

        if (answer.equals(problem.getAnswer())) {
            totalAnswersCorrect++;

            return true;
        } else {
            return false;
        }
    }

    /**
 * Returns the last answer.
 */
    public String getLastAnswer() {
        return this.lastAnswer;
    }

    /**
 * Returns true if there are more problems left to solve.
 */
    public boolean hasMoreProblems() {
        return !problems.isEmpty();
    }

    /**
 * Returns the total number of questions answered correctly so far.
 */
    public int getTotalAnswersCorrect() {
        return totalAnswersCorrect;
    }

    /**
 * Returns tips and suggestions to help the student improve his score based on 
 * the total number of questions answered correctly.
 */
    public String getSuggestions() {
        return (totalAnswersCorrect >= 8)
               ? "Excellent! Please view this website for further knowledge: http://www.ipl.org/ref/POTUS"
               : "You need to study harder! Here is a website to help http://www.ipl.org/ref/POTUS";
    }

    /**
 * Encapsulates a problem with a solution.
 */
    class Problem {
        private int number;
        private String question;
        private String answer;

        Problem(int number, String question, String answer) {
            this.number = number;
            this.question = question;
            this.answer = answer;
        }

        /**
 * Returns the problem number.
 */
        public int getNumber() {
            return this.number;
        }

        /**
 * Returns the question.
 */
        public String getQuestion() {
            return this.question;
        }

        /**
 * Returns the answer to the problem.
 */
        String getAnswer() {
            return answer;
        }
    } ///:~ Problem
} ///:~ Agent