account.java

来自「《Java与模式》一书的源代码」· Java 代码 · 共 36 行

package com.javapatterns.templatemethod.InterestRate;

public abstract class Account
{
    protected String accountNumber;

    public Account()
    {
        accountNumber = null;
    }

    public Account(String accountNumber)
    {
        this.accountNumber = accountNumber;
    }

    public final double calculateInterest()
    {
        double interestRate = doCalculateInterestRate();
        String accountType = doCalculateAccountType();
        double amount = calculateAmount(accountType, accountNumber);

        return amount * interestRate;
    }

    protected abstract String doCalculateAccountType();

    protected abstract double doCalculateInterestRate();

    public final double calculateAmount(String accountType, String accountNumber)
    {
        //retrieve amount from database...here is only a mock-up
        return 7243.00D;
    }
}