listitemtag.java

招标投标网上系统

/*
 *********************************************************************
 *  文件 : $Workfile: ListItemTag.java $
 *  项目 : 腾龙1.2
 *  公司 : 沈阳东软软件股份有限公司
 *  日期 : $Date: 03-12-10 18:21 $
 *  说明 :
 **********************************************************************
 * 版本历史:
 * $Log: /4 开发工作目录/src/com/neusoft/taglibs/list/ListItemTag.java $
 * 
 * 1     03-12-10 18:21 Lihg
 * 
 * 1     03-12-10 8:44 Lihg
 *
 * 1     03-05-20 9:46 Lihg
 *********************************************************************
 */
package com.neusoft.taglibs.list;

import java.io.*;
import java.lang.reflect.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

import com.neusoft.util.CommonUtil;

/**
 *  这个tag会根据相应的数据对象List，列出单个数据对象，与ListTag配套使用
 *
 *@author     <a href="mailto:[e-mail]">李红国</a>
 *@created    2003年5月19日
 */

public class ListItemTag
    extends TagSupport {

  private Object item = null;
  private String property = null;

  private String precisionString = null;

  /**
   *  构造对象 ListItemTag
   */
  public ListItemTag() {
    super();
  }

  /**
   *  设定ListItemTag object-property的属性值
   *
   *@param  property  属性 property 的值
   */
  public void setProperty(String property) {
    this.property = property;
  }

  /**
   *  遇到tag时触发
   *
   *@return                      操作标志
   *@exception  JspTagException  异常描述
   */
  public int doStartTag() throws JspTagException {
    // check if items tag is in list tag
    ListTag listTag = (ListTag) findAncestorWithClass(this, ListTag.class);

    if (listTag == null) {
      throw new JspTagException(
          "ListDataTag: ListItem tag not inside items tag");
    }
    item = listTag.getCurrentItem();
    if (listTag == null) {
      throw new JspTagException("ListDataTag: There is no item to list.");
    }
    return SKIP_BODY;
  }

  /**
   *  tag结束时触发
   *
   *@return                      描述返回值信息
   *@exception  JspTagException  异常描述
   */
  public int doEndTag() throws JspTagException {
    // print out attribute
    try {
      JspWriter out = pageContext.getOut();
      String targetText = getText();
      //if (format != null) targetText = formatText(targetText);
      pageContext.getRequest().setAttribute(property, targetText);
      out.print(targetText);
    }
    catch (IOException ioe) {
      System.err.println("ListDataTag: Error printing attribute: " + ioe);
      throw new JspTagException("ListDataTag: IO Error printing attribute.");
    }
    return (EVAL_PAGE);
  }

  /**
   *  Using the current Object use reflection to obtain the String data from
   *  the element method the same as a JavaBean would use: <br>
   *  <br>
   *  e.g. a getXXXX method which has no parameters <br>
   *  The target method is the property attribute The default method that is
   *  called is the toString method on the object.
   *
   *@return                      属性 text的值
   *@exception  JspTagException  异常描述
   */
  private String getText() throws JspTagException {

    String targetMethod = "getValue";

    Object returnValue = null;
    try {
      // no arguments are needed
      Class[] args = {
          String.class};
      Object[] params = {
          property};
      Method m = item.getClass().getMethod(targetMethod, args);
      if (m == null) {
        throw new JspTagException(
            "ListDataTag: There is no method by the name of " + targetMethod);
      }
      returnValue = m.invoke(item, params);
    }
    catch (java.lang.NoSuchMethodException ex) {
      throw new JspTagException("ListDataTag: Method for property " + property +
                                " not found.");
    }
    catch (java.lang.reflect.InvocationTargetException ex) {
      throw new JspTagException("ListDataTag: Error calling method " +
                                targetMethod + ":" + ex);
    }
    catch (java.lang.IllegalAccessException ex) {
      throw new JspTagException("ListDataTag: Error calling method " +
                                targetMethod + ":" + ex);
    }
    // do casting of Integers and Dobules here
    if (returnValue instanceof java.lang.String) {
      returnValue = (String) returnValue;
    }
    else if (returnValue instanceof java.lang.Integer) {
      returnValue = ( (Integer) returnValue).toString();

    }
    else if (returnValue instanceof java.lang.Double) {
      returnValue = ( (Double) returnValue).toString();
    }
    else if (returnValue instanceof java.lang.Float) {
      returnValue = ( (Float) returnValue).toString();
    }
    else if (returnValue instanceof java.math.BigDecimal) {
      returnValue = ( (java.math.BigDecimal) returnValue).toString();
    }
    else if (returnValue == null) {
      returnValue = "";
    }
    else {
      throw new JspTagException("ListDataTag: Error extracting property: Can not handle the return type for property " +
                                property);
    }
    return CommonUtil.parseHtml( (String) returnValue);
  }

}