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Java程序组织:如何摆脱这个庞大的case语句?

switch-statement oop architecture java

sixtyfootersdude · 技术社区 · 15 年前

public class WordDescriptor {

    public static final String noun = "N";
    public static final String plural = "p";
    public static final String nounPhrase = "h";
    public static final String usuParticipleVerb = "V";
    public static final String transitiveVerb = "t";
    public static final String intransitiveVerb = "i";
    public static final String adjective = "A";
    public static final String adverb = "v";
    public static final String conjunction = "C";
    public static final String preposition = "P";
    public static final String interjection = "!";
    public static final String pronoun = "r";
    public static final String definiteArticle = "D";
    public static final String indefiniteArticle = "I";
    public static final String nominative = "o";
    public static final String defaultTag = "?";

    private String word; // where word is one of the constants defined above.  

    public String getWord(){
        return word;
    }

    public String setWord(){
        return word;
    }

    /** For debugging only.  
     * 
     * @param s
     * @return
     */
    protected static String getKind(String s){
        if(s.equals(noun)){
            return "noun";
        }else if(s.equals(plural)){
            return "plural";
        }else if(s.equals(nounPhrase)){
            return "nounPhrase";
        }else if(s.equals(usuParticipleVerb)){
            return "usuParticipleVerb";
        }else if(s.equals(transitiveVerb)){
            return "transitiveVerb";
        }else if(s.equals(intransitiveVerb)){
            return "intransitiveVerb";
        }else if(s.equals(adjective)){
            return "adjective";
        }else if(s.equals(adverb)){
            return "adverb";
        }else if(s.equals(conjunction)){
            return "conjunction";
        }else if(s.equals(preposition)){
            return "preposition";
        }else if(s.equals(interjection)){
            return "interjection";
        }else if(s.equals(pronoun)){
            return "pronoun";
        }else if(s.equals(definiteArticle)){
            return "definiteArticle";
        }else if(s.equals(indefiniteArticle)){
            return "indefiniteArticle";
        }else if(s.equals(nominative)){
            return "nominative";
        } else if(s.equals(defaultTag)){
            return "defaultTag";
        }else{
            return "other: "+s;
        }
    }

}

这几乎是我能想象到的最难看的代码。我知道我可以通过使用一个案例来让它更好一点,但是它仍然非常难看。我的问题是:

我怎样才能使它美丽?我在考虑做:

- 类名词,含子类:
  - 单数的
- 类动词
- 类副词

编辑:如果我真的采取了第二种方法,我甚至不知道这些类会是什么样子。举个例子:

public abstract class WordDescriptor {

   public String toString();

}

public class Noun extends WordDescriptor {

    public String toString(){
        return "Noun";
    }
}

public class Plural extends Noun{
    public String toString(){
        return "Plural";
    }
}

3 回复 | 直到 15 年前

Barry Brown 15 年前

您可以使用枚举类型执行某些操作。

public enum SpeechPart
{
    NOUN ("noun"),
    PLURAL ("plural"),
    NOUNPHRASE ("noun phrase"),
    ADVERB ("adverb"),
    ADJECTIVE ("adjective"),
    CONJUNCTION ("conjunction"),
    VERB ("verb");

    private String english;

    SpeechPart(String inEnglish)
    {
        this.english = inEnglish;
    }

    public String toString() { return english; }
}

SpeechPart dog = SpeechPart.NOUN;
SpeechPart ran = SpeechPart.VERB;
SpeechPart quickly = SpeechPart.ADVERB;

然后你可以看到他们的词性:

System.out.println(dog.toString());
System.out.println(quickly);        // Implicit call to toString()

Decorator Pattern

另一个建议是列举修饰符:

public enum SpeechModifier
{
    SINGULAR,
    PLURAL,
    FIRST_PERSON,
    SECOND_PERSON,
    THIRD_PERSON,
    PRESENT,
    PAST,
    PERFECT,
    PROGRESSIVE;
}

public class Word
{
    String word;
    SpeechPart part;
    EnumSet<SpeechModifier> modifiers;
}

现在你可以模拟一个完整的单词:

Word w1 = new Word();
w1.word = "bouncing";
w1.part = SpeechPart.VERB;
w1.modifiers = EnumSet<SpeechModifier>.of(SpeechModifier.PRESENT, SpeechModifier.PROGRESSIVE);

然而,这个解决方案并不能阻止非感官的组合,比如第一人称名词过去。

Gabe Timothy Khouri 15 年前

我只需要创建一个从缩写到完整描述的字典或地图。那么 getKind 将在映射中查找其输入并返回结果,或者 other

Chris Diver 15 年前

你能用一本有代码的字典吗( s