Complete Source Code Listings

 

Included Files: application.xml

 

<?xml version="1.0"?>

<!DOCTYPE application PUBLIC "-//Sun Microsystems, Inc.//DTD J2EE Application 1.2//EN" "http://java.sun.com/j2ee/dtds/application_1_2.dtd">

<application>

  <display-name>Tag Library Test Application</display-name>

  <description>

     A sample Tag Library Test Application

  </description>

  <module>

    <web>

      <web-uri>TagLib.war</web-uri>

      <context-root>/TagLib</context-root>

    </web>

  </module>

</application>

 

 

Included Files: web.xml

 

<?xml version="1.0" encoding="UTF-8"?>

 

<!DOCTYPE web-app PUBLIC '-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN' 'http://java.sun.com/dtd/web-app_2_3.dtd'>

 

<web-app>

   <display-name>Tag Library Test Application</display-name>

   <description>

      Web module that contains two JSP's.

   </description>

   <welcome-file-list>

      <welcome-file>untitled1.jsp</welcome-file>

   </welcome-file-list>

  

 <taglib>

  <taglib-uri>/TagLib</taglib-uri>

  <taglib-location>/WEB-INF/TableDisplay.tld</taglib-location>

 </taglib>

   

</web-app>

 

 

Included Files: TableDisplay.tld

 

<?xml version = '1.0' encoding = 'windows-1252'?>

<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">

<taglib>

   <tlibversion>1.0</tlibversion>

   <jspversion>1.1</jspversion>

   <shortname>TableDisplay</shortname>

   <uri>WEB-INF\TableDisplay</uri>

   <info>A short description...</info> 

  

      <tag>

      <name>TableDisplayQuery</name>

      <tagclass>mypackage.TableDisplayQuery</tagclass>

      <bodycontent>JSP</bodycontent>

      <attribute>

      <name>dataSource</name>

      <rtexprvalue>true</rtexprvalue>

      </attribute>

      <attribute>

      <name>userName</name>

      <rtexprvalue>true</rtexprvalue>

      </attribute>

      <attribute>     

      <name>password</name>

      <rtexprvalue>true</rtexprvalue>

      </attribute>

      <attribute>     

      <name>JDBCClass</name>

      <rtexprvalue>true</rtexprvalue>

      </attribute>           

      <attribute>      

      <name>connectionURL</name>

      <rtexprvalue>true</rtexprvalue>

      </attribute>       

      <attribute>

      <name>queryString</name>

      <required>true</required>

      <rtexprvalue>true</rtexprvalue>

      </attribute>

      </tag>

  

</taglib>

 

 

Complete JSP Source Code

 

<%@ page contentType="text/html;charset=windows-1252"%>

<%@ taglib uri="WEB-INF/TableDisplay.tld" prefix="myTags"%>
<html>

<head>
<meta HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1252" />
<title>Testing Table Display Tags</title>
</head>

<body>

<b>
<!-- THE TAG LIBRARY ----->

<myTags:TableDisplayQuery

connectionURL="jdbc:rmi://localhost:1099/jdbc:cloudscape:CloudscapeDB;create=true" JDBCClass="COM.cloudscape.core.RmiJdbcDriver"

userName="APP" queryString="SELECT * FROM USER_INFO" />

<!-- ------------------ -->
<br />
<br />
</b><strong><font size="4" face="Arial">The following statement generated the table
above...</font></strong><hr color="#000000" width="75%" align="left" style="word-spacing: 0; text-align: left; margin-top: 0; margin-bottom: 0" />
<p><br />
<font face="Courier New">&lt;myTags:TableDisplayQuery<br />
connectionURL= &quot;jdbc:rmi://localhost:1099/jdbc:cloudscape:CloudscapeDB;create=true&quot;<br />
JDBCClass=&quot;COM.cloudscape.core.RmiJdbcDriver&quot;<br />
userName=&quot;APP&quot; password=&quot;&quot;<br />
queryString=&quot;SELECT * FROM USER_INFO&quot; /&gt;</font><b><br />
<br />

<!-- THE TAG LIBRARY ----->
<myTags:TableDisplayQuery

dataSource="jdbc/MoneyPlanDS"

userName="APP" queryString="SELECT * FROM USER_INFO" />

<!-- ------------------ -->
<br />
<br />
</b><font size="4" face="Arial">The following statement generated the table above...<br />
In this example, notice the use of the data source attribute</font><br />
</p>
<hr color="#000000" width="75%" align="left" />
<p><font face="Courier New">&lt;myTags:TableDisplayQuery dataSource= &quot;jdbc/MoneyPlanDS&quot;<br />
userName=&quot;APP&quot; password=&quot;&quot;<br />
queryString=&quot;SELECT * FROM USER_INFO&quot; /&gt;</font></p>

</body>

</html>
 

 

 

 

Complete Java Source Code: TableTagUtils.java

 

package mypackage;

import java.util.Collection;

import javax.servlet.jsp.JspWriter;

import javax.servlet.jsp.PageContext;

import java.sql.ResultSet;

import java.util.Collection;

 

public class TableTagUtils

{

 

 

  /**

   * displays the actual table

   *

   * @see #displayTitles

   * @param JspWriter out writer from the page the tag is in

   * @param ResultSet rs java.sql.ResultSet from the executed query

   * @param Collection t uses a collection of strings as the input

   * @exception NONE

   * @return String to be displayed

   */

  protected static void writeTheOutput( JspWriter out, ResultSet rs, Collection t )

  {

        try

        {

            out.print("<CENTER>");

            out.print("<TABLE border='2' >");

            out.print("<!-- heading row -->");      

            out.print( displayTitles(t) );

 

            int colCount = t.size();

 

            while ( rs.next() ){

              out.write("<TR>");

              for (int i = 0; i < colCount; i++)

              {

                out.write("<TD>" + rs.getObject(i+1).toString() + "</TD>");               

              }

              out.print("</TR>");

            }        

        } catch(Exception e)  {

            e.printStackTrace();

        } finally {
            try { out.print("</TABLE>"); } catch (Exception e) {}
            try { out.print("</CENTER>"); } catch (Exception e) {}
        }

  }

  /**

   * generates the string for the table.. this string is the column header

   * listing the names of all of the columns

   *

   * @see #generateColumnTitles

   * @see #writeTheOutput  

   * @param Collection t uses a collection of strings as the input

   * @exception NONE

   * @return String to be displayed

   */

      protected static String displayTitles( Collection t ) {

        StringBuffer b = new StringBuffer();

        String d;

       

        b.append("<TR>");

        java.util.Iterator it = t.iterator();

       

        while (it.hasNext()) {

            d = (String)it.next();

            b.append("<TD><STRONG>" + d + "</STRONG></TD>");

        }

        b.append("</TR>");

        return b.toString();

    }

 

  /**

   * Extract the column titles from the jdbc result set meta data, this is really

   * a helper function for the over all utility tag to quickly display results

   * of a query.

   *

   * @see #java.sql.ResultSetMetaData

   * @param ResultSet rs comments

   * @exception javax.servlet.jsp.JspException if ANY Error occurs

   * @return an ArrayList containing all of the colum names

   */

  protected static Collection generateColumnTitles(ResultSet rs) throws javax.servlet.jsp.JspException

  {

    java.util.ArrayList columnTitles = new java.util.ArrayList();   

 

    try {

      java.sql.ResultSetMetaData rsMD = rs.getMetaData();

 

      int x = rsMD.getColumnCount();

      for (int i = 1; i <= x; i++)

      {

        columnTitles.add(rsMD.getColumnName(i));

      } 

    } catch ( Exception e )  {

      throw new javax.servlet.jsp.JspException("Could not get result set");

    }

    return columnTitles;

  }

 

  protected static void checkStringVars( String s, String name ) throws Exception

  {

    if (( s == null ) || s.equals(""))

    {

      throw new javax.servlet.jsp.JspException("Atrtribute \"" + name + "\" cannot be blank or NULL!");

    }

  }

 

 

}

 

 

Complete Java Source Code: TableDisplayQuery.java

 

package mypackage;

import javax.servlet.jsp.tagext.TagSupport;

import javax.servlet.jsp.tagext.BodyTagSupport;

import javax.servlet.jsp.tagext.BodyContent;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.JspTagException;

import javax.servlet.jsp.JspWriter;

import javax.servlet.jsp.PageContext;

import javax.servlet.ServletRequest;

import java.io.PrintWriter;

import java.sql.ResultSet;

import java.sql.DriverManager;

import java.util.Collection;

import java.util.ArrayList;

import mypackage.TableTagUtils.*;

import javax.naming.InitialContext;

import javax.naming.Context;

import javax.rmi.PortableRemoteObject;

 

public class TableDisplayQuery extends BodyTagSupport

{

 

  private ResultSet resultSet;

  private Collection columnTitles;

  private String queryString;

  private javax.sql.DataSource ds;

  private java.sql.Connection conn;

  private String JDBCClass;

  private String userName;

  private String password;

  private String connectionURL;

 

  /**

   * Method called at start of tag.

   * @return EVAL_BODY_INCLUDE

   */

  public int doStartTag() throws JspException

  {

 

    try {

      if ( ds == null ) {

        mypackage.TableTagUtils.checkStringVars(JDBCClass, "JDBCClass");

        mypackage.TableTagUtils.checkStringVars(connectionURL,"connectionURL");

        mypackage.TableTagUtils.checkStringVars(userName,"userName");

       

        Class.forName(JDBCClass);

        conn = DriverManager.getConnection(connectionURL,

                     userName, password);

      } else {

        conn = this.ds.getConnection();   

      }

   

      resultSet = executeTheQuery();

      if ( columnTitles == null )  columnTitles = mypackage.TableTagUtils.generateColumnTitles(resultSet);

      TableTagUtils.writeTheOutput( pageContext.getOut(), resultSet, columnTitles );

    } catch (Exception e) {

      throw new javax.servlet.jsp.JspException(e.toString());       

    }

    finally {

        try { if (resultSet != null) resultSet.close(); } catch ( Exception e) {};

        try { if (conn != null) conn.close();} catch ( Exception e) {};

    }

   

    return SKIP_BODY;

  }

 

 

  /**

   * Method called at end of tag.

   * @return EVAL_PAGE

   */

  public int doEndTag()

  {

    return EVAL_PAGE;

  }

 

 

  /**

   * Method is invoked after every body evaluation to control whether the body will be reevaluated or not.

   * @return SKIP_BODY

   */

  public int doAfterBody() throws JspException

  {

    return SKIP_BODY;

  }

 

 

  public void setQueryString( String qs )

  {

    queryString = qs;

  }

 

  public void setJDBCClass( String className ) { JDBCClass = className; }

 

  public void setUserName( String s ) { userName = s; }

  public void setPassword( String s ) { password = s; }

  public void setConnectionURL( String theURL ) { connectionURL = theURL; }

 

  public void setDataSource( String dsName ) throws javax.servlet.jsp.JspException

  {

    try {

      Context ic = new InitialContext();

      ds = (javax.sql.DataSource) ic.lookup(dsName);

    } catch (Exception e) {

      throw new javax.servlet.jsp.JspException(e.getMessage());

    } 

  }

 

 

 

  private java.sql.ResultSet executeTheQuery() throws javax.servlet.jsp.JspException

  {

    java.sql.ResultSet results = null;

   

    try {

      java.sql.Statement stmt = conn.createStatement();

      results =  stmt.executeQuery( this.queryString );

    } catch (Exception e ) {

      throw new javax.servlet.jsp.JspException(e.getLocalizedMessage());     

    }

    return results;

  }

}

 

 

 

Complete Java Source Code: TableDisplayRS.java

 

package mypackage;

import javax.servlet.jsp.tagext.TagSupport;

import javax.servlet.jsp.tagext.BodyTagSupport;

import javax.servlet.jsp.tagext.BodyContent;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.JspTagException;

import javax.servlet.jsp.JspWriter;

import javax.servlet.jsp.PageContext;

import javax.servlet.ServletRequest;

import java.io.PrintWriter;

import java.sql.ResultSet;

import java.util.Collection;

import java.util.Collections;

import java.util.ArrayList;

import mypackage.TableTagUtils;

 

public class TableDisplayRS extends BodyTagSupport

{

 

  private ResultSet resultSet;

  private Collection columnTitles;

 

  /**

   * Method called at start of tag.

   * @return EVAL_BODY_INCLUDE

   */

  public int doStartTag() throws JspException

  {

        try

        {

            JspWriter out = pageContext.getOut();

            out.print("<CENTER>");

            out.print("<TABLE border='2' >");

            out.print("<!-- heading row -->");

 

            if ( columnTitles == null ) columnTitles = TableTagUtils.generateColumnTitles(resultSet);

           

            out.print( TableTagUtils.displayTitles(columnTitles) );

 

            int colCount = columnTitles.size();

 

 

            while ( resultSet.next() ){

              out.write("<TR>");

              for (int i = 0; i < colCount; i++)

              {

                out.write("<TD>" + resultSet.getObject(i+1).toString() + "</TD>");               

              }

            }

            } catch ( Exception e) {

              throw new JspException( e.getLocalizedMessage());

            }

 

    return SKIP_BODY;

  }

 

 

  /**

   * Method called at end of tag.

   * @return EVAL_PAGE

   */

  public int doEndTag()

  {

    return EVAL_PAGE;

  }

 

 

  /**

   * Method is invoked after every body evaluation to control whether the body will be reevaluated or not.

   * @return SKIP_BODY

   */

  public int doAfterBody() throws JspException

  {

    return SKIP_BODY;

  }

 

  private ResultSet getResultSet()

  {

    return resultSet;

  }

 

  public void setResultSet(Object newResultSet)

  {

    resultSet = (ResultSet)newResultSet;

  }

 

  private Collection getColumnTitles()

  {

    return columnTitles;

  }

 

  public void setColumnTitles(Collection newColumnTitles)

  {

    columnTitles = newColumnTitles;

  }

 

}