Java设计模式-解释其模式（六）

package com.utstar.pattern.expression;

public abstract class Expression{
    public abstract void interpret(Context c);
}

 

package com.utstar.pattern.expression;


import java.util.*;

public class Context{
    public String content;
    public List<Expression> list;
    public Context(){
        list = new ArrayList<Expression>();
    }
    public void setContent(String c){
        this.content = c;
    }
    public String getContent(){
        return this.content;
    }
    public void add(Expression e){
        this.list.add(e);
    }
    public List<Expression> getList(){
        return this.list;
    }
}

package com.utstar.pattern.expression;

public class SimpleExpression extends Expression{
    public void interpret(Context c){
        System.out.println("Simple.");
    }
}

package com.utstar.pattern.expression;

public class AdvancedExpression extends Expression{
    public void interpret(Context c){
        System.out.println("Advanced.");
    }
}

package com.utstar.pattern.expression;

public class Test{
    public static void main(String args[]){
        Context text = new Context();
        text.add(new SimpleExpression());
        text.add(new AdvancedExpression());
        text.add(new SimpleExpression());
        for(Expression exp:text.getList())
            exp.interpret(text);
    }
}