/*
* 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 org.pentaho.reporting.engine.classic.core.Element;
import org.pentaho.reporting.engine.classic.core.event.PageEventListener;
import org.pentaho.reporting.engine.classic.core.event.ReportEvent;
import org.pentaho.reporting.libraries.base.util.ObjectUtilities;
/**
* The ItemHideFunction hides equal values in a group. Only the first changed value is printed. This function uses the
* property <code>element</code> to define the name of the element in the ItemBand that should be made visible or
* invisible by this function. The property <code>field</code> defines the field in the datasource or the expression
* which should be used to determine the visibility.
* <p/>
* In simple cases, this function can be replaced with a style-formula on the visibly-stylekey:
* <code>=NOT(ISCHANGED("fieldname"))</code>. In addition to the simple case, this function behaves special on
* pagebreaks and intermediate group changes.
*
* @author Thomas Morgner
*/
public class ItemHideFunction extends AbstractFunction implements PageEventListener, LayoutProcessorFunction
{
/**
* The last object. This is part of the internal state and therefore not serialized.
*/
private transient Object lastObject;
/**
* The 'visible' flag. This is part of the internal state and therefore not serialized.
*/
private transient boolean visible;
/**
* The 'first-in-group' flag. This is part of the internal state and therefore not serialized.
*/
private transient boolean firstInGroup;
/**
* A flag indicating whether a group start resets the visiblity of the element.
*/
private boolean ignoreGroupBreaks;
/**
* A flag indicating whether a page start resets the visiblity of the element.
*/
private boolean ignorePageBreaks;
/**
* The name of the element that should be hidden.
*/
private String element;
/**
* The data-row column that should be checked for changed values.
*/
private String field;
/**
* Constructs an unnamed function. <P> Make sure to set the function name before it is used, or function
* initialisation will fail.
*/
public ItemHideFunction()
{
}
/**
* Constructs a named function. <P> The field must be defined before using the function.
*
* @param name The function name.
*/
public ItemHideFunction(final String name)
{
this();
setName(name);
}
/**
* Returns whether a group start resets the visiblity of the element.
*
* @return false, if group breaks reset the visiblity, true otherwise.
*/
public boolean isIgnoreGroupBreaks()
{
return ignoreGroupBreaks;
}
/**
* Defines whether a group start resets the visiblity of the element.
*
* @param ignoreGroupBreaks false, if group breaks reset the visiblity, true otherwise.
*/
public void setIgnoreGroupBreaks(final boolean ignoreGroupBreaks)
{
this.ignoreGroupBreaks = ignoreGroupBreaks;
}
/**
* Returns whether a page start resets the visiblity of the element.
*
* @return false, if page breaks reset the visiblity, true otherwise.
*/
public boolean isIgnorePageBreaks()
{
return ignorePageBreaks;
}
/**
* Returns whether a page start resets the visiblity of the element.
*
* @param ignorePageBreaks false, if page breaks reset the visiblity, true otherwise.
*/
public void setIgnorePageBreaks(final boolean ignorePageBreaks)
{
this.ignorePageBreaks = ignorePageBreaks;
}
/**
* Returns the name of the element in the item band that should be set visible/invisible.
*
* @return The element name.
*/
public String getElement()
{
return element;
}
/**
* Sets the name of the element in the item band that should be set visible/invisible.
*
* @param name the element name (must not be null).
*/
public void setElement(final String name)
{
this.element = name;
}
/**
* Returns the field used by the function. The field name corresponds to a column name in the report's data-row.
*
* @return The field name.
*/
public String getField()
{
return field;
}
/**
* Sets the field name for the function. The field name corresponds to a column name in the report's data-row.
*
* @param field the field name.
*/
public void setField(final String field)
{
this.field = field;
}
/**
* Receives notification that a row of data is being processed. Reads the data from the field defined for this
* function and hides the field if the value is equal to the last value and the this is not the first row of the item
* group.
*
* @param event Information about the event.
*/
public void itemsAdvanced(final ReportEvent event)
{
final Object fieldValue = event.getDataRow().get(getField());
// is visible when last and current object are not equal
// first element in group is always visible
if (firstInGroup == true)
{
visible = true;
firstInGroup = false;
}
else
{
visible = (ObjectUtilities.equal(lastObject, fieldValue) == false);
}
lastObject = fieldValue;
final Element[] elements = FunctionUtilities.findAllElements(event.getReport().getItemBand(), getElement());
for (int i = 0; i < elements.length; i++)
{
final Element e = elements[i];
e.setVisible(visible);
}
}
/**
* Resets the state of the function when a new ItemGroup has started.
*
* @param event the report event.
*/
public void itemsStarted(final ReportEvent event)
{
if (ignoreGroupBreaks == false)
{
lastObject = null;
firstInGroup = true;
}
}
/**
* Returns the function value, in this case the visibility of the defined element.
*
* @return The function value.
*/
public Object getValue()
{
if (visible)
{
return Boolean.TRUE;
}
return Boolean.FALSE;
}
/**
* Receives notification that a page is completed.
*
* @param event The event.
*/
public void pageFinished(final ReportEvent event)
{
}
/**
* Receives notification that a new page is being started.
*
* @param event The event.
*/
public void pageStarted(final ReportEvent event)
{
if (ignorePageBreaks)
{
return;
}
final Object fieldValue = event.getDataRow().get(getField());
// is visible when last and current object are not equal
// first element in group is always visible
// after a page start, reset the function ...
visible = true;
firstInGroup = true;
lastObject = fieldValue;
final Element[] elements = FunctionUtilities.findAllElements(event.getReport().getItemBand(), getElement());
for (int i = 0; i < elements.length; i++)
{
final Element e = elements[i];
e.setVisible(visible);
}
}
/**
* Return a completly separated copy of this function. The copy does no longer share any changeable objects with the
* original function.
*
* @return a copy of this function.
*/
public Expression getInstance()
{
final ItemHideFunction ih = (ItemHideFunction) super.getInstance();
ih.lastObject = null;
return ih;
}
/**
* Receives notification that the report has started.
*
* @param event the event.
*/
public void reportInitialized(final ReportEvent event)
{
lastObject = null;
firstInGroup = true;
}
}