import.java

Novocode的 SWT 控件框架 丰富了MDI功能

/*******************************************************************************
 * Copyright (c) 2004 Stefan Zeiger and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.novocode.com/legal/epl-v10.html
 * 
 * Contributors:
 *     Stefan Zeiger ([e-mail]) - initial API and implementation
 *******************************************************************************/

package com.novocode.naf.resource;

import org.w3c.dom.Element;

import com.novocode.naf.app.NAFException;


/**
 * An <code>&lt;import&gt;</code> statement.
 *
 * @author Stefan Zeiger ([e-mail])
 * @since Nov 6, 2004
 * @version $Id: Import.java,v 1.2 2005/05/08 18:49:27 szeiger Exp $
 */

public final class Import
{
  private String as, clazz, prefix, suffix, unqualifiedClass, using;


  public Import(String clazz, String as, String using)
  {
    this.clazz = clazz;
    this.as = as;
    
    int sep = clazz.indexOf('*');
    if(sep != -1)
    {
      prefix = clazz.substring(0, sep);
      suffix = clazz.substring(sep+1);
    }
    else
    {
      sep = clazz.lastIndexOf('.');
      if(sep != -1) unqualifiedClass = clazz.substring(sep+1);
      else unqualifiedClass = clazz;
    }
  }
  
  
  public static Import parse(Element e) throws NAFException
  {
    String clazz = e.getAttribute("class");
    String as    = e.getAttribute("as");
    String using = e.getAttribute("using");
    if(as != null && as.length() == 0) as = null;
    if(clazz == null || clazz.length() == 0)
      throw new NAFException("An <import> element must contain a non-empty \"class\" attribute");
    if(clazz.indexOf('*') != -1 && as != null)
      throw new NAFException("An <import> element with a class pattern may not contain an \"as\" attribute");
    return new Import(clazz, as, using);
  }
  
  
  public String toString()
  {
    String s = "[import "+clazz;
    if(as != null) s += " as "+as;
    return s + "]";
  }
  
  
  private String classNameFor(String s)
  {
    if(as != null && as.equals(s)) return clazz;
    else if(prefix != null) return prefix + s + suffix;
    else if(unqualifiedClass.equals(s)) return clazz;
    else return null;
  }
  
  
  public Class classFor(String s)
  {
    String n = classNameFor(s);
    if(n == null) return null;
    try { return Class.forName(n); }
    catch(ClassNotFoundException ex) { return null; }
  }
  
  
  public String getUsing()
  {
    return using;
  }
}