解释器设计模式_lua解释器交互模式_解释器模式c语言(13)

public class StrategyPatternDemo {
    public static void main(String[] args) {
        Context context = new Context(new OperationAdd());
        System.out.println("10 + 5 = " + context.executeStrategy(10, 5));

        context = new Context(new OperationSubstract());
        System.out.println("10 - 5 = " + context.executeStrategy(10, 5));

        context = new Context(new OperationMultiply());
        System.out.println("10 * 5 = " + context.executeStrategy(10, 5));
    }
}

请求以命令的形式包裹在对象中，并传给调用对象。调用对象寻找可以处理该命令的合适的对象，并把该命令传给相应的对象，该对象执行命令。解释器设计模式

public intece Command {
    void execute();
}

public class AddCommand implements Command {
    private Document document;

    public AddCommand(Document document) {
        this.document = document;
    }

    @Override
    public void execute() {
        this.document.add();
    }
}

public class RedoCommand implements Command {
    private Document document;

    public RedoCommand(Document document) {
        this.document = document;
    }

    @Override
    public void execute() {
        this.document.redo();
    }
}

public class UndoCommand implements Command {
    private Document document;

    public UndoCommand(Document document) {
        this.document = document;
    }

    @Override
    public void execute() {
        this.document.undo();
    }
}

public class Document {
    public static StringBuffer sbr = new StringBuffer();
    /**
     * 计数器
     */
    public static int count = 0;

    /**
     * 撤销实现方法
     */
    public void undo() {
        System.out.println("调用撤销实现方法，字符串递减");
        sbr.deleteCharAt(sbr.length() - 1);
        count--;
        System.out.println("当前文本为：" + sbr.toString());
    }

    /**
     * 恢复实现方法
     */
    public void redo() {
        System.out.println("调用恢复实现方法，字符串递加");
        this.sbr.append(count);
        count++;
        System.out.println("当前文本为：" + sbr.toString());
    }

    /**
     * 执行实现方法
     */
    public void add() {
        System.out.println("调用执行实现方法，字符串递加");
        this.sbr.append(count);
        count++;
        System.out.println("当前文本为：" + sbr.toString());
    }
}

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