package org.apache.struts.util;

import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyContent;

public class ResponseUtils {
  protected static MessageResources messages = MessageResources.getMessageResources("org.apache.struts.util.LocalStrings");
  
  public static String filter(String value) {
    if (value == null)
      return null; 
    char[] content = new char[value.length()];
    value.getChars(0, value.length(), content, 0);
    StringBuffer result = new StringBuffer(content.length + 50);
    for (int i = 0; i < content.length; i++) {
      switch (content[i]) {
        case '<':
          result.append("&lt;");
          break;
        case '>':
          result.append("&gt;");
          break;
        case '&':
          result.append("&amp;");
          break;
        case '"':
          result.append("&quot;");
          break;
        case '\'':
          result.append("&#39;");
          break;
        default:
          result.append(content[i]);
          break;
      } 
    } 
    return result.toString();
  }
  
  public static void write(PageContext pageContext, String text) throws JspException {
    JspWriter writer = pageContext.getOut();
    try {
      writer.print(text);
    } catch (IOException e) {
      RequestUtils.saveException(pageContext, e);
      throw new JspException(messages.getMessage("write.io", e.toString()));
    } 
  }
  
  public static void writePrevious(PageContext pageContext, String text) throws JspException {
    JspWriter writer = pageContext.getOut();
    if (writer instanceof BodyContent)
      writer = ((BodyContent)writer).getEnclosingWriter(); 
    try {
      writer.print(text);
    } catch (IOException e) {
      RequestUtils.saveException(pageContext, e);
      throw new JspException(messages.getMessage("write.io", e.toString()));
    } 
  }
}