jstlcorechoose.java

来自「RESIN 3.2 最新源码」· Java 代码 · 共 109 行

/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *   Free SoftwareFoundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.jsp.java;

import com.caucho.jsp.JspParseException;
import com.caucho.vfs.WriteStream;

import java.io.IOException;

public class JstlCoreChoose extends JstlNode {
  /**
   * Children are handled specially.
   */
  public void addChild(JspNode node)
    throws JspParseException
  {
    if (node instanceof JstlCoreWhen)
      super.addChild(node);
    else if (node instanceof JstlXmlWhen)
      super.addChild(node);
    else if (node instanceof JstlCoreOtherwise)
      super.addChild(node);
    else
      throw error(L.l("<{0}> is not allowed as a child of <{1}>.  Only <when> and <otherwise> are allowed children.",
                      node.getTagName(), getTagName()));
  }

  /**
   * Whitespace text is ignored.
   */
  public JspNode addText(String text)
    throws JspParseException
  {
    if (! isWhitespace(text))
      throw error(L.l("text is not allowed as a child of <{1}>.  Only <c:when> and <c:otherwise> are allowed children.",
                      getTagName()));

    return null;
  }

  /**
   * Validity checking.
   */
  public void endElement()
    throws JspParseException
  {
    if (_children == null || _children.size() == 0)
      throw error(L.l("<{0}> must have at least one <c:when> clause.",
                      getTagName()));
  }

  /**
   * Generates the XML text representation for the tag validation.
   *
   * @param os write stream to the generated XML.
   */
  public void printXml(WriteStream os)
    throws IOException
  {
    os.print("<c:choose>");

    printXmlChildren(os);

    os.print("</c:choose>");
  }

  /**
   * Generates the code for the c:out tag.
   */
  public void generate(JspJavaWriter out)
    throws Exception
  {
    for (int i = 0; i < _children.size(); i++) {
      JspNode node = _children.get(i);
      
      if (i != 0)
        out.print("else ");

      node.generate(out);
    }
  }
}