软件设计-Tutorial18

```mermaid
classDiagram
    class Expression {
        <<interface>>
        +interpret() String
    }

    class Direction {
        -String direction
        +interpret() String
    }

    class Action {
        -String action
        +interpret() String
    }

    class Distance {
        -int distance
        +interpret() String
    }

    class SimpleExpression {
        -Expression direction
        -Expression action
        -Expression distance
        +interpret() String
    }

    class CompositeExpression {
        -List~Expression~ expressions
        +addExpression(Expression expression) void
        +interpret() String
    }

    class InterpreterContext {
        +parse(String input) Expression
    }

    Expression <|.. Direction
    Expression <|.. Action
    Expression <|.. Distance
    Expression <|.. SimpleExpression
    Expression <|.. CompositeExpression
    InterpreterContext --> CompositeExpression
    CompositeExpression o-- Expression

```

package Tutorial17;

import java.util.ArrayList;
import java.util.List;

// 1. Expression接口，定义解析接口
interface Expression {
    String interpret();
}

// 2. Direction、Action和Distance表达式类，用于解释基本指令
class Direction implements Expression {
    private String direction;

    public Direction(String direction) {
        this.direction = direction;
    }

    @Override
    public String interpret() {
        return switch (direction) {
            case "up" -> "向上";
            case "down" -> "向下";
            case "left" -> "向左";
            case "right" -> "向右";
            default -> throw new IllegalArgumentException("无效的方向: " + direction);
        };
    }
}

class Action implements Expression {
    private String action;

    public Action(String action) {
        this.action = action;
    }

    @Override
    public String interpret() {
        return switch (action) {
            case "move" -> "移动";
            case "run" -> "奔跑";
            default -> throw new IllegalArgumentException("无效的动作: " + action);
        };
    }
}

class Distance implements Expression {
    private int distance;

    public Distance(int distance) {
        this.distance = distance;
    }

    @Override
    public String interpret() {
        return distance + "个单位";
    }
}

// 3. SimpleExpression类，解释单一的方向-动作-距离指令
class SimpleExpression implements Expression {
    private Expression direction;
    private Expression action;
    private Expression distance;

    public SimpleExpression(Expression direction, Expression action, Expression distance) {
        this.direction = direction;
        this.action = action;
        this.distance = distance;
    }

    @Override
    public String interpret() {
        return direction.interpret() + action.interpret() + distance.interpret();
    }
}

// 4. CompositeExpression类，用于处理“and”复合表达式
class CompositeExpression implements Expression {
    private List<Expression> expressions = new ArrayList<>();

    public void addExpression(Expression expression) {
        expressions.add(expression);
    }

    @Override
    public String interpret() {
        StringBuilder result = new StringBuilder();
        for (int i = 0; i < expressions.size(); i++) {
            result.append(expressions.get(i).interpret());
            if (i < expressions.size() - 1) {
                result.append("再");
            }
        }
        return result.toString();
    }
}

// 5. 解释器上下文类，解析并生成对应的表达式
class InterpreterContext {
    public Expression parse(String input) {
        String[] parts = input.split(" and ");
        CompositeExpression composite = new CompositeExpression();

        for (String part : parts) {
            String[] tokens = part.split(" ");
            Expression direction = new Direction(tokens[0]);
            Expression action = new Action(tokens[1]);
            Expression distance = new Distance(Integer.parseInt(tokens[2]));
            composite.addExpression(new SimpleExpression(direction, action, distance));
        }

        return composite;
    }
}

// 6. 测试类
public class Main {
    public static void main(String[] args) {
        InterpreterContext context = new InterpreterContext();

        String input1 = "up move 5";
        Expression expression1 = context.parse(input1);
        System.out.println("输入: " + input1 + "，输出: " + expression1.interpret());

        String input2 = "down run 10 and left move 20";
        Expression expression2 = context.parse(input2);
        System.out.println("输入: " + input2 + "，输出: " + expression2.interpret());
    }
}