沒有上下文類 Java 的策略模式

以下是使用沒有上下文類的策略模式的簡單示例。實現介面有兩種實現策略，以不同的方式解決同一問題。通過指定所需策略，EnglishTranslation 類的使用者可以呼叫 translate 方法並選擇他們想要用於翻譯的策略。

// The strategy interface
public interface TranslationStrategy {
    String translate(String phrase);
}

// American strategy implementation 
public class AmericanTranslationStrategy implements TranslationStrategy {

    @Override
    public String translate(String phrase) {
        return phrase + ", bro";
    }
}

// Australian strategy implementation     
public class AustralianTranslationStrategy implements TranslationStrategy {

    @Override
    public String translate(String phrase) {
        return phrase + ", mate";
    }
}

// The main class which exposes a translate method
public class EnglishTranslation {

    //  translate a phrase using a given strategy
    public static String translate(String phrase, TranslationStrategy strategy) {
        return strategy.translate(phrase);
    }

    // example usage
    public static void main(String[] args) {

        // translate a phrase using the AustralianTranslationStrategy class
        String aussieHello = translate("Hello", new AustralianTranslationStrategy());
        // Hello, mate

        // translate a phrase using the AmericanTranslationStrategy class    
        String usaHello = translate("Hello", new AmericanTranslationStrategy());
        // Hello, bro
    }
}