primitivecommandnode.java~2~

《深入浅出设计模式》的完整源代码

package littlecompiler;
// <primitive command> ::= PRINT <string> | SPACE | BREAK | LINEBREAK
public class PrimitiveCommandNode implements Node {
  private String name;
  private String text;

  public void parse (Context context) {
    name = context.currentToken ();
    context.skipToken (name);
    if (!name.equals ("PRINT") && !name.equals ("BREAK") &&
        !name.equals ("LINEBREAK") && !name.equals ("SPACE")) {
      System.err.println ("Undefined Command");
    }

    if (name.equals ("PRINT")) {
      text = context.currentToken ();
      name += text;
      context.nextToken ();
    }
  }
  public void execute() {
      if(name.equals("PRINT"))
          System.out.print(text);
      else if(name.equals("SPACE"))
          System.out.print(" ");
      else if(name.equals("BREAK"))
          System.out.println();
      else if(name.equals("LINEBREAK"))
          System.out.println("\n------------------------------");
  }

  public String toString() {
      return name;
  }
}