extractpropertytag.java

招标投标网上系统

/*
 * $Id: ExtractPropertyTag.java,v 1.8 2001/10/24 04:15:27 gmurray Exp $
 * Copyright 2000 Sun Microsystems, Inc. All rights reserved.
 * Copyright 2000 Sun Microsystems, Inc. Tous droits r?erv?.
 */

package com.neusoft.taglibs.smart;

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

/**
 *
 * This class allows you to retrieve a parameter from the request and output it to the page
 * This should allow you to avoid expressions for extracting parameter info.
 *
 */

public class ExtractPropertyTag
    extends BodyTagSupport {

  private String sourceId = null;
  private String sourceScope = null;
  private String targetScope = null;
  private String property = null;
  private Object targetObject = null;
  private String destinationId = null;

  private ArrayList parameters = new ArrayList();

  public ExtractPropertyTag() {
    super();
  }

  public void setId(String sourceId) {
    this.sourceId = sourceId;
  }

  public void setScope(String sourceScope) {
    this.sourceScope = sourceScope.toLowerCase();
  }

  public void setDestinationId(String destinationId) {
    this.destinationId = destinationId;
  }

  public void setDestinationScope(String targetScope) {
    this.targetScope = targetScope.toLowerCase();
  }

  public void setProperty(String property) {
    this.property = property;
  }

  public int doStartTag() throws JspTagException {
    targetObject = null;
    if (sourceScope.equals("request")) {
      targetObject = pageContext.getRequest().getAttribute(sourceId);
    }
    else if (sourceScope.equals("session")) {
      targetObject = pageContext.getSession().getAttribute(sourceId);
    }
    else if (sourceScope.equals("page")) {
      targetObject = pageContext.getAttribute(sourceId);
    }
    if (targetObject == null) {
      throw new JspTagException("ExtractPropertyTag: Target Item " + sourceId +
                                " not found in " + sourceScope + " scope.");
    }
    return EVAL_BODY_TAG;
  }

  public int doEndTag() throws JspTagException {
    Object extractedObject = getProperty();
    if (targetScope.equals("request")) {
      pageContext.getRequest().setAttribute(destinationId, extractedObject);
    }
    else if (targetScope.equals("session")) {
      pageContext.getSession().setAttribute(destinationId, extractedObject);
    }
    else if (targetScope.equals("page")) {
      pageContext.setAttribute(destinationId, extractedObject);
    }
    parameters = null;
    sourceId = null;
    sourceScope = null;
    targetScope = null;
    property = null;
    targetObject = null;
    destinationId = null;
    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
   */
  private Object getProperty() throws JspTagException {
    //String targetMethod = property.substring(0,1).toUpperCase() + property.substring(1,property.length());
    String targetMethod = property;
    Object returnValue = null;
    try {
      // set arguments if  needed
      Class[] args = null;
      Object[] params = null;
      if (parameters == null) {
        Class[] tempArgs = {};
        args = tempArgs;
        Object[] tempParams = {};
        params = tempParams;
      }
      else {
        // set the parameters here
        args = new Class[parameters.size()];
        params = new Object[parameters.size()];
        Iterator it = parameters.iterator();
        int index = 0;
        while (it.hasNext()) {
          ParameterItem item = (ParameterItem) it.next();
          if (item.getType().equals("java.lang.String")) {
            args[index] = String.class;
            params[index] = item.getParameter();
          }
          else if (item.getType().equals("int")) {
            args[index] = int.class;
            params[index] = new Integer(item.getParameter());
          }
          else if (item.getType().equals("boolean")) {
            args[index] = boolean.class;
            params[index] = new Boolean(item.getParameter());
          }
          index++;
        }
      }
      //Method[] mm=targetObject.getClass().getMethods();
      //for(int i=0;i<mm.length;i++){
      //	////System.out.printn(mm[i].getName());
      // }
      Method m = targetObject.getClass().getMethod(property, args);

      ////System.out.printn(m.getName());
      if (m == null) {
        throw new JspTagException(
            "ExtractPropertyTag: There is no method by the name of " +
            targetMethod);
      }
      returnValue = m.invoke(targetObject, params);
    }
    catch (java.lang.NoSuchMethodException ex) {
      throw new JspTagException("ExtractPropertyTag: Method for property " +
                                property + " not found.");
    }
    catch (java.lang.reflect.InvocationTargetException ex) {
      ex.printStackTrace();
      throw new JspTagException("ExtractPropertyTag: Error calling method " +
                                targetMethod + ":" + ex);
    }
    catch (java.lang.IllegalAccessException ex) {
      throw new JspTagException("ExtractPropertyTag: Error calling method " +
                                targetMethod + ":" + ex);
    }
    return returnValue;
  }

  public void addParameter(String parameter, String type) {
    if (parameters == null) {
      parameters = new ArrayList();
    }
    parameters.add(new ParameterItem(parameter, type));
  }

  // This class represents a parameter for internal use in this class only

  class ParameterItem {

    private String parameter;
    private String type;

    ParameterItem(String parameter, String type) {
      this.parameter = parameter;
      this.type = type;
    }

    public String getParameter() {
      return parameter;
    }

    public String getType() {
      return type;
    }

  }
}