Java8 Lambda表达式+策略设计模式

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/**
 * 策略模式代表了一类算法的通用解决方案，可以在运行时选择那种方案
 */
public interface Strategy {
    boolean execute(String s);
}
class IsAllLowerCase implements Strategy{
    @Override
    public boolean execute(String s) {
        return s.matches("[a-z]+");
    }
}
class IsNumric implements Strategy{
    @Override
    public boolean execute(String s) {
        return s.matches("\\d+");
    }
}
public class Validator {
    private final Strategy strategy;

    public Validator(Strategy strategy) {
        this.strategy = strategy;
    }
    public boolean validate(String s){
        return strategy.execute(s);
    }
}

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import org.junit.Test;

import static org.junit.Assert.*;

public class ValidatorTest {

    @Test
    public void validate() {
        ///java8以前的策略模式实现
        Validator validator = new Validator(new IsNumric());
        System.out.println(validator.validate("aaaa"));
        ///使用Lambda表达式
        Validator numericValidate = new Validator((s)->s.matches("\\d+"));
        System.out.println(numericValidate.validate("89"));
        Validator lowerValidate = new Validator((s)->s.matches("[a-z]+"));
        System.out.println(lowerValidate.validate("addd"));
    }
}

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