External Custom Webject Examples

package examples.customwebjects;

import com.infoengine.util.IEException;
import com.infoengine.exception.fatal.IEInternalServiceException;
import com.infoengine.procunit.webject.GroupWebjectException;
import com.infoengine.object.factory.*;

import java.util.Enumeration;
import java.util.Vector;

/**
* NumericColumnWebjects
*
* supplies implementation for two simple webjects: 
* <li>totalColumn - return the numeric total of a column
* <li>averageColumn - return the numeric average of a column
* The implementation is simple minded using a 'double' to calculate
* totals and averages. No formating of the results is performed.
* 
* Example: 
* <ie:webject name="Query-Objects" type="OBJ">
* <ie:param name="INSTANCE" data="jdbcAdapter"/>
* <ie:param name="CLASS" data="EMP"/>
* <ie:param name="WHERE" data="()"/>
* <ie:param name="GROUP_OUT" data="employees"/>
* </ie:webject>
*
* <ie:webject name="Total-Column" type="EXT" use="examples.custom
webjects.NumericColumnWebjects">
* <ie:param name="COLUMN" data="SAL"/>
* <ie:param name="GROUP_IN" data="employees"/>
* <ie:param name="GROUP_OUT" data="total_salary"/>
* </ie:webject>
*
* <ie:webject name="Average-Column" type="EXT" use="examples.custom
webjects.NumericColumnWebjects">
* <ie:param name="COLUMN" data="SAL"/>
* <ie:param name="GROUP_IN" data="employees"/>
* <ie:param name="GROUP_OUT" data="average_salary"/>
* </ie:webject>
**/

public class NumericColumnWebjects
{

/**
 * return a list of column elements
 *
 * @return Vector
 * @exception IEException if required values aren't found within
the webject
 **/

 private static Vector getColumnElements ( Task task ) throws IE
Exception {
 Webject w = task.getWebject();
 String grp_out = null;
 String column = null;
 String grp_in = null;
 Group group_in = null;

 // get the column name to retrieve
 Param param = w.getParam ( "COLUMN" );
 if ( param == null )
 throw new GroupWebjectException ( "NumericColumnWebjects:
no COLUMN" );

 column = param.getData();

 // if GROUP_IN not supplied take the default group off the VDB
 param = w.getParam ( "GROUP_IN" );
 if ( param == null )
 group_in = task.getGroupIn();
 else
 group_in = task.getVdb ( param.getData() );
 if ( group_in == null )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no GROUP_IN" );

 // build the Vector of column contents

 int element_count = group_in.getElementCount();
 Vector elements = new Vector ();
 for ( int i = 0; i < element_count; i++ ) {
 Element e = group_in.getElementAt ( i );

 Vector ev = e.getValues ( column, true );

 if ( ev == null ) continue;

 for ( int j = 0; j < ev.size (); ++j )
 elements.addElement ( ev.elementAt ( j ) );
 }
 if ( !(elements.size() > 0) )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no COLUMN \"" + column
\"" );

 return elements;
 }
/**
 * given a input group, column name, and group out name
 * generate the numeric average of the column's contents
 * return the value in a group.
 *
 * @return Task - response
 * @exception IEException - if required parameters are
missing or column
 * is not numeric.
 **/

 public static Task averageColumn ( Task task ) throws IE
Exception {
 try {
 String grp_out = null;
 String column = null;
 Webject w = task.getWebject();
 // get the name of the group to create
 Param param = w.getParam ( "GROUP_OUT" );
 if ( param == null )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no GROUP_OUT" );
 grp_out = param.getData();
 // get the name of the column to average
 param = w.getParam ( "COLUMN" );
 if ( param == null )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no COLUMN" );

 column = param.getData();

 Vector elements = getColumnElements ( task );

 // total the values
 Object val;
 Double dval;
 double average = 0;
 for ( Enumeration en = elements.elements();
 en.hasMoreElements (); ) {
 val = en.nextElement();
 dval = new Double ( val.toString() );
 average += dval.doubleValue();
 }
 // calculate the average
 average = average / elements.size();

 Element elem = new Element ();
 Att att = new Att ( column + " average" );
 att.addValue ( "" + average );
 elem.addAtt ( att );
 Group group_out = new Group ( grp_out );
 group_out.setElement ( elem );

 Task response = new Task();
 response.addVdb ( group_out );

 return response;
 } catch ( Exception exc ) {
 exc.printStackTrace ( System.err );
 if ( exc instanceof IEException )
 throw (IEException)exc;
 throw new IEInternalServiceException ( exc );
 }
 }
/**
 * given a input group, column name, and group out name
 * generate the numeric total of the column's contents
 * return the value in a group.
 *
 * @return Task - response
 * @exception IEException - if required parameters are
missing or column
 * is not numeric.
 **/

 public static Task totalColumn ( Task task ) throws IE
Exception {
 try {
 String grp_out = null;
 String column = null;

 Webject w = task.getWebject();

 // get the name of the group to create
 Param param = w.getParam ( "GROUP_OUT" );
 if ( param == null )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no GROUP_OUT" );

 grp_out = param.getData();

 // get the name of the column to total
 param = w.getParam ( "COLUMN" );
 if ( param == null )
 throw new GroupWebjectException
 ( "NumericColumnWebjects: no COLUMN" );

 column = param.getData();

 Vector elements = getColumnElements ( task );

 // calculate the total
 Object val;
 Double dval;
 double total = 0;
 for ( Enumeration en = elements.elements();
 en.hasMoreElements (); ) {
 val = en.nextElement();
 dval = new Double ( val.toString() );
 total += dval.doubleValue();
 }

 // build GROUP_OUT and response
 Element elem = new Element ();
 Att att = new Att ( column + " total" );
 att.addValue ( "" + total );
 elem.addAtt ( att );
 Group group_out = new Group ( grp_out );
 group_out.setElement ( elem );

 Task response = new Task();
 response.addVdb ( group_out );

 return response;
 } catch ( Exception exc ) {
 exc.printStackTrace ( System.err );
 if ( exc instanceof IEException )
 throw (IEException)exc;
 throw new IEInternalServiceException ( exc );
 }
 }
}