java - 干净的代码，如何改进一个类

Question

我有我的 CommandFormatValidator 类，它检查输入的字符串是否符合任何预定义的模式。随着时间的推移，类实现了越来越多的新模式，导致了类的以下形式:

import java.util.StringTokenizer;
import java.util.regex.Pattern;

public class CommandFormatValidator {

    private Pattern adlPatternAll = Pattern
            .compile("^ACTV/(READ|ADD|DEL|RPL)/ADL.*");

    private Pattern adlPatternAddDefault = Pattern
            .compile("^ACTV/ADD/ADL/(DFLTTY((/([A-Z0-9]{7})){1,5})|DFLMIN(/[0-9]{1,4}))");

    private Pattern adlPatternDeleteTtymailGeneral = Pattern
            .compile("^ACTV/(DEL|READ)/ADL/TTYMAIL(/[A-Z0-9]{7})?");

//around 20 more pattern declarations...

public void validate(Object payload){

        String command = (String)payload;

        if (adlPatternAll.matcher(command).matches()) {
            if (!adlPatternAddDefault.matcher(command).matches()) {
                if (!adlPatternAddCityTty.matcher(command).matches()) {
                    if (!adlPatternAddCityFltTty.matcher(command).matches()) {
                        if (!adlPatternAdd.matcher(command).matches()) {
                            if (!adlPatternDelDefault.matcher(command).matches()) {
                                if (!adlPatternDel.matcher(command).matches()) {
                                    if (!adlPatternDelCityFltTty.matcher(command).matches()) {
                                        if (!adlPatternRpl.matcher(command).matches()) {
                                            if (!adlPatternRead.matcher(command).matches()) {
                                                if (!adlPatternReadCityFlt.matcher(command).matches()) {
                                                    if(!adlPatternAddTtymail.matcher(command).matches()) {
                                                        if( !adlPatternDeleteTtymailGeneral.matcher(command).matches()) {
                                                            if (!adlPatternDeleteTtymail.matcher(command).matches()) {
                                                                throw new ServiceException(CommandErrors.INVALID_FORMAT);
                                                            }
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

现在我想清理这个类。有谁知道我怎样才能实现这一目标？我将特别感谢任何可以应用于我的案例的设计模式。

Answer 1

您可以将它们全部列出在一个数组中，然后迭代该数组。

顺便说一句:使用 matches() 时不需要 ^ anchor 。

不知道您是否在第一次测试中错过了!，但这里没有:

public class CommandFormatValidator {

    private Pattern adlPatternAll = Pattern
            .compile("^ACTV/(READ|ADD|DEL|RPL)/ADL.*");

    private Pattern adlPatternAddDefault = Pattern
            .compile("^ACTV/ADD/ADL/(DFLTTY((/([A-Z0-9]{7})){1,5})|DFLMIN(/[0-9]{1,4}))");

    private Pattern adlPatternDeleteTtymailGeneral = Pattern
            .compile("^ACTV/(DEL|READ)/ADL/TTYMAIL(/[A-Z0-9]{7})?");

    //around 20 more pattern declarations...

    private Pattern[] adlAll = { adlPatternAddDefault
                               , adlPatternDeleteTtymailGeneral
                               //more
                               };

    public void validate(Object payload){
        String command = (String)payload;
        if (! adlPatternAll.matcher(command).matches())
            return;
        for (Pattern p : adlAll)
            if (p.matcher(command).matches())
                return;
        throw new ServiceException(CommandErrors.INVALID_FORMAT);
    }
}