/*
* ILabelFormatter.java of project jchart2d, a formatter for labels
* of axis.
* Copyright (C) 2004 - 2011 Achim Westermann.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* If you modify or optimize the code in a useful way please let me know.
* Achim.Westermann@gmx.de
*
*/
package info.monitorenter.gui.chart;
import info.monitorenter.util.units.AUnit;
import java.beans.PropertyChangeListener;
import java.io.Serializable;
/**
* An interface used by Axis to format labels and determine the maximum width
* for the labels.
*
* In order to get as much labels as possible on the Chart2D's axes, an Axis
* should be configured in a way that reduces the return value of the method
* {@link #getMaxAmountChars()}.
*
*
* @see info.monitorenter.gui.chart.axis.AAxis
*
* @author Achim Westermann
*
* @version $Revision: 1.5 $
*/
public interface IAxisLabelFormatter extends Serializable {
/**
* Constant for {@link java.beans.PropertyChangeEvent} fired
* when the configuration changes.
*/
public static final String PROPERTY_FORMATCHANGE = "IAxisLabelFormatter.PROPERTY_FORMATCHANGE";
/**
* Registers a property change listener that will be informed about changes of
* the property identified by the given propertyName.
*
*
* @param propertyName
* the name of the property the listener is interested in
*
* @param listener
* a listener that will only be informed if the property identified
* by the argument propertyName changes
*
*
*/
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener);
/**
* Provide a String for the value. Subclasses should override the label
* formatting here. The raw value is passed here to allow a general treatment.
* Transformations of this raw value should be done here (e.g. division by
* multiples of 1000 for scientific unit system display, date formatting,...).
*
*
* @param value
* the value to format.
*
* @return the formatted value.
*/
public String format(double value);
/**
* Returns the maximum amount of characters that will be returned from
* {@link #format(double)}.
*
*
* @return the maximum amount of characters that will be returned from
* {@link #format(double)}.
*
*/
public int getMaxAmountChars();
/**
* Returns the minimum change in the value to format that will cause to return
* a different formatted String.
*
* To achieve two different formatted Strings to be returned from the format
* method the corresponding values given to the format method have to differ
* at least by this value.
*
* Some implementations (e.g. a formatter for date) have to use their own
* format method an increas a value to determine when the first change will
* occur. This is expensive and it's recommended that this action is performed
* once only and the result is stored. Additionally this routine has to start
* with an "even" (see {@link #getNextEvenValue(double, boolean)}) value to
* get a correct result (the distance from even number to even number).
*
*
* @return the minimum change in the value to format that will cause to return
* a different formatted String.
*/
double getMinimumValueShiftForChange();
/**
* Returns the next "even" value to the given one. "Even" means that the
* format method will exactly return the String for the value and not cut or
* round any information. A label String created with an "even" number will be
* exactly at the position it describes.
*
*
* @param value
* the value to get the next "even" value for.
* @param ceiling
* if true, the next higher number will returned, else the next lower
* one.
* @return the next "even" value to the given one.
*
*/
double getNextEvenValue(double value, boolean ceiling);
/**
* Returns the unit that is currently used by this formatter.
*
*
* @return the unit that is currently used by this formatter.
*/
public AUnit getUnit();
/**
* Callback method invoked by the corresponding
* {@link info.monitorenter.gui.chart.axis.AAxis} upon start of a paint
* iteration of the {@link Chart2D}.
*
*
*/
public void initPaintIteration();
/**
* The reverse operation to {@link #format(double)}.
*
* The given argument has to be in the format that will be generated by that
* method or exceptions may be thrown.
* test.parse(test.format(d))== d
* has to be true if no rounding occurs by the formatter.
*
*
* @param formatted
* a String in the format that will be produced by
* method {@link #format(double)}.
*
* @return the parsed number.
*
* @throws NumberFormatException
* if the format of the argument is invalid.
*
*/
public Number parse(String formatted) throws NumberFormatException;
/**
* Deregisters a property change listener that has been registerd for
* listening on the given property.
*
*
* @param listener
* a listener that will only be informed if the property identified
* by the argument propertyName changes
*
* @param property
* the property the listener was registered to.
*/
public void removePropertyChangeListener(final String property, PropertyChangeListener listener);
/**
* Allows the {@link info.monitorenter.gui.chart.axis.AAxis} to register
* itself with the given formatter so that it may get information about the
* data (e.g. range) it has to format.
*
*
* This method should only be invoked by
* {@link info.monitorenter.gui.chart.axis.AAxis}, all other invocations will
* cause trouble.
*
*
* @param axis
* the axis to gain information about.
*/
public void setAxis(IAxis axis);
}
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