/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2009 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.function;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Arrays;
/**
* An expression that takes values from one or more fields and returns the average of them.
*
* @author Thomas Morgner
* @deprecated this has been replaced by the ColumnAverageExpression.
*/
public class AverageExpression extends AbstractExpression
{
/**
* An ordered list containing the fieldnames used in the expression.
*/
private ArrayList fieldList;
/**
* The scale-property defines the precission of the divide-operation.
*/
private int scale;
/**
* The rounding-property defines the precission of the divide-operation.
*/
private int roundingMode;
private static final BigDecimal ZERO = new BigDecimal("0");
/**
* Creates a new expression. The fields used by the expression are defined using properties named '0', '1', ... 'N'.
* These fields should contain {@link Number} instances.
*/
public AverageExpression()
{
this.fieldList = new ArrayList();
scale = 14;
roundingMode = BigDecimal.ROUND_HALF_UP;
}
/**
* Returns the defined rounding mode. This influences the precision of the divide-operation.
*
* @return the rounding mode.
* @see java.math.BigDecimal#divide(java.math.BigDecimal,int)
*/
public int getRoundingMode()
{
return roundingMode;
}
/**
* Defines the rounding mode. This influences the precision of the divide-operation.
*
* @param roundingMode the rounding mode.
* @see java.math.BigDecimal#divide(java.math.BigDecimal,int)
*/
public void setRoundingMode(final int roundingMode)
{
this.roundingMode = roundingMode;
}
/**
* Returns the scale for the divide-operation. The scale influences the precision of the division.
*
* @return the scale.
*/
public int getScale()
{
return scale;
}
/**
* Defines the scale for the divide-operation. The scale influences the precision of the division.
*
* @param scale the scale.
*/
public void setScale(final int scale)
{
this.scale = scale;
}
/**
* Returns the average of the values.
*
* @return a BigDecimal instance.
*/
public Object getValue()
{
final Number[] values = collectValues();
BigDecimal total = ZERO;
int count = 0;
for (int i = 0; i < values.length; i++)
{
final Number n = values[i];
if (n != null)
{
total = total.add(new BigDecimal(n.toString()));
count++;
}
}
if (count > 0)
{
return total.divide(new BigDecimal(String.valueOf(count)), scale, roundingMode);
}
return ZERO;
}
/**
* collects the values of all fields defined in the fieldList.
*
* @return an Objectarray containing all defined values from the datarow
*/
private Number[] collectValues()
{
final Number[] retval = new Number[this.fieldList.size()];
for (int i = 0; i < this.fieldList.size(); i++)
{
final String field = (String) this.fieldList.get(i);
final Object o = getDataRow().get(field);
if (o instanceof Number)
{
retval[i] = (Number) o;
}
}
return retval;
}
/**
* Clones the expression.
*
* @return A copy of this expression.
*/
public Expression getInstance()
{
final AverageExpression ae = (AverageExpression) super.getInstance();
ae.fieldList = (ArrayList) fieldList.clone();
return ae;
}
/**
* Returns the defined fields as array.
*
* @return the fields
*/
public String[] getField()
{
return (String[]) fieldList.toArray(new String[fieldList.size()]);
}
/**
* Defines all fields as array. This completely replaces any previously defined fields.
*
* @param fields the new list of fields.
*/
public void setField(final String[] fields)
{
this.fieldList.clear();
this.fieldList.addAll(Arrays.asList(fields));
}
/**
* Returns the defined field at the given index-position.
*
* @param index the position of the field name that should be queried.
* @return the field name at the given position.
*/
public String getField(final int index)
{
return (String) this.fieldList.get(index);
}
/**
* Defines the field in the field-list at the given index.
*
* @param index the position in the list, where the field should be defined.
* @param field the name of the field.
*/
public void setField(final int index, final String field)
{
if (this.fieldList.size() == index)
{
this.fieldList.add(field);
}
else
{
this.fieldList.set(index, field);
}
}
/**
* Returns the number of fields defined in this expression.
*
* @return the number of fields.
*/
public int getFieldCount()
{
return fieldList.size();
}
}