/*
* 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 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.function;
import java.math.BigDecimal;
/**
* Computes the horizontal average over all columns specified in the field-list. The average will be computed over all
* fields of the current data-row, it will not be computed for all rows in the group. For that use the
* {@link org.pentaho.reporting.engine.classic.core.function.ItemAvgFunction} instead.
* <p/>
* Non numeric and null-columns will be treated as zero for the task of summing up all members. Whether these fields are
* used counted as valid fields can be controlled with the 'onlyValidFields' flag.
*
* @author Thomas Morgner
* @deprecated the same can be achived with a formula "AVG([column1], [column2], [column3])"
*/
public class ColumnAverageExpression extends ColumnAggregationExpression {
/**
* A flag defining whether non-numeric and null-values should be ignored.
*/
private boolean onlyValidFields;
/**
* A flag defining whether the expression should return infinity if there are no valid fields. If set to false, this
* expression returns null instead.
*/
private boolean returnInfinity;
/**
* 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;
/**
* Default Constructor.
*/
public ColumnAverageExpression() {
this.returnInfinity = true; // for backward compatiblity.
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, whether the expression returns infinity if there are no valid fields. If set to false, this expression
* returns null instead.
*
* @return true, if infinity is returned, false otherwise.
*/
public boolean isReturnInfinity() {
return returnInfinity;
}
/**
* Defines, whether the expression returns infinity if there are no valid fields. If set to false, this expression
* returns null instead.
*
* @param returnInfinity
* true, if infinity is returned, false otherwise.
*/
public void setReturnInfinity( final boolean returnInfinity ) {
this.returnInfinity = returnInfinity;
}
/**
* Returns, whether non-numeric and null-values are ignored for the average-computation.
*
* @return true, if the invalid fields will be ignored, false if they count as valid zero-value fields.
*/
public boolean isOnlyValidFields() {
return onlyValidFields;
}
/**
* Defines, whether non-numeric and null-values are ignored for the average-computation.
*
* @param onlyValidFields
* true, if the invalid fields will be ignored, false if they count as valid zero-value fields.
*/
public void setOnlyValidFields( final boolean onlyValidFields ) {
this.onlyValidFields = onlyValidFields;
}
/**
* Computes the horizontal average of all field in the field-list. The average will be computed over all fields of the
* current data-row, it will not be computed for all rows in the group. For that use the
* {@link org.pentaho.reporting.engine.classic.core.function.ItemAvgFunction} instead.
*
* @return the value of the function.
*/
public Object getValue() {
final Object[] values = getFieldValues();
BigDecimal computedResult = new BigDecimal( 0 );
int count = 0;
for ( int i = 0; i < values.length; i++ ) {
final Object value = values[i];
if ( value instanceof Number == false ) {
continue;
}
final Number n = (Number) value;
final BigDecimal nval = new BigDecimal( n.toString() );
computedResult = computedResult.add( nval );
count += 1;
}
if ( onlyValidFields ) {
if ( count == 0 ) {
if ( returnInfinity == false ) {
return null;
}
if ( computedResult.signum() == -1 ) {
return new Double( Double.NEGATIVE_INFINITY );
} else {
return new Double( Double.POSITIVE_INFINITY );
}
}
return computedResult.divide( new BigDecimal( count ), scale, roundingMode );
}
if ( values.length == 0 ) {
if ( returnInfinity == false ) {
return null;
}
if ( computedResult.signum() == -1 ) {
return new Double( Double.NEGATIVE_INFINITY );
} else {
return new Double( Double.POSITIVE_INFINITY );
}
}
return computedResult.divide( new BigDecimal( values.length ), scale, roundingMode );
}
}