Generator.java :  » Web-Framework » anvil » anvil » script » Java Open Source

/*
 * $Id: Generator.java,v 1.9 2002/09/16 08:05:03 jkl Exp $
 *
 * Copyright (c) 2002 Njet Communications Ltd. All Rights Reserved.
 *
 * Use is subject to license terms, as defined in
 * Anvil Sofware License, Version 1.1. See LICENSE 
 * file, or http://njet.org/license-1.1.txt
 */
package anvil.script;

import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import anvil.Location;
import anvil.core.Any;
import anvil.core.AnyBindingEnumeration;
import anvil.core.AnyClass;
import anvil.script.compiler.FunctionBase;
import anvil.java.util.BindingEnumeration;

/**
 * interface Generator
 *
 * @author: Jani Lehtimki
 */
public class Generator extends StackFrame implements BindingEnumeration
{
  protected GeneratorDispatcher _dispatcher;
  protected Any     _next;
  protected boolean _hasmore = true;
  protected int     _index;
  protected boolean _running = false;
  protected int     _state;
  protected Any     _wrapper;
  
  
  public Generator(Context context, Module script, AnyClass self, Function function, int maxlocals, int line)
  {
    super(script, self, function, maxlocals, line, true);
    _escape     = context.consumeEscape();
    _wrapper    = new AnyBindingEnumeration(this);
    _dispatcher = ((FunctionBase)_function).getGeneratorDispatcher(context);
  }

  
  public String toString()
  {
    return "generator "+_function+" at state "+_state;
  }

  
  public final void detach()
  {
    //
  }
  
  public Any getWrapper()
  {
    return _wrapper;
  }


  public int getState()
  {
    return _state;
  }


  public void setState(int state)
  {
    _state = state;
  }


  public void setClosedState()
  {
    _state = -1;
  }


  public boolean hasMoreElements()
  {
    if (_hasmore) {
      Any next = _next;
      if (next == null) {
        return getNextElement();
      } else {
        return true;
      }
    }
    return false;
  }


  public Object nextKey()
  {
    return Any.create(_index);
  }


  public Object nextElement()
  {
    _index++;
    try {
      return _next;
    } finally {
      _next = null;
    }
  }


  protected boolean getNextElement()
  {
    Context context = Context.getInstance();
    
    synchronized(this) {
      if (_running) {       
        throw context.BadState("Generator '"+this+"' is already running");
      }
      _running = true;
    }
    
    try {
      context.push(this);
      Any next = _dispatcher.execute(context, _self, this);
      if (_state == -1) {
        _hasmore = false;
      } 
      _next = next;  

    } finally {
      context.pop();
      _running = false;
    }
    
    return _hasmore;
  }

}