commandnode.java

来自「《深入浅出设计模式》的完整源代码」· Java 代码 · 共 21 行

package littlecompiler;
//命令类，相应的文法为:<command> ::= <repeat command> | <primitive command>
public class CommandNode implements Node {
  private Node node;
  public void parse (Context context) {
    if (context.currentToken ().equals ("REPEAT")) {
      node = new RepeatCommandNode ();
      node.parse (context);
    }
    else {
      node = new PrimitiveCommandNode ();
      node.parse (context);
    }
  }
  public void execute() {
      node.execute();
  }
  public String toString() {
      return node.toString();
  }
}