/*
* AUnit.java, base class for units in jchart2d.
* 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.util.units;
import java.io.Serializable;
/**
* A unit.
* <p>
*
* @author <a href='mailto:Achim.Westermann@gmx.de'>Achim Westermann </a>
*
* @version $Revision: 1.10 $
*
* @see info.monitorenter.util.units.UnitFactory
*
* @see info.monitorenter.util.units.IUnitSystem
*
* @see info.monitorenter.util.units.UnitSystemSI
*/
public abstract class AUnit extends Object implements Serializable {
/** Generated <code>serialVersionUID</code>. **/
private static final long serialVersionUID = -8890511971185813347L;
/**
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + this.m_decimals;
long temp;
temp = Double.doubleToLongBits(this.m_factor);
result = prime * result + (int) (temp ^ (temp >>> 32));
result = prime * result + ((this.m_unitName == null) ? 0 : this.m_unitName.hashCode());
return result;
}
/**
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
AUnit other = (AUnit) obj;
if (this.m_decimals != other.m_decimals) {
return false;
}
if (Double.doubleToLongBits(this.m_factor) != Double.doubleToLongBits(other.m_factor)) {
return false;
}
if (this.m_unitName == null) {
if (other.m_unitName != null) {
return false;
}
} else if (!this.m_unitName.equals(other.m_unitName)) {
return false;
}
return true;
}
/** Decimals for rounding. */
protected int m_decimals = 2;
/**
* The factor a result of {@link #getValue(double)} had to be multiplied with
* if the real (unitless) value has to be calculated.
*/
protected double m_factor;
/**
* The next smaller unit to this one within this unit's {@link IUnitSystem}.
* <p>
*/
protected AUnit m_nexLowerUnit;
/**
* The next greater unit to this one within this unit's {@link IUnitSystem}.
* <p>
*/
protected AUnit m_nextHigherUnit;
/**
* The short unit name of this unit a result of {@link #getValue(double)} has
* to be related with to know the this result is displayed in a unit.
* <p>
*/
protected String m_unitName;
/**
* Protected constructor to ensure package access only.
* <p>
*
* Use {@link UnitFactory#getInstance()} and
* {@link UnitFactory#getUnit(double, IUnitSystem)} to obtain a proper unit.
* <p>
*
*/
protected AUnit() {
// nop
}
/**
* Returns the number of decimals that should be be taken into account if the
* method {@link #getValue(double)} is invoked (rounding).
* <p>
*
* @return the number of decimals that should be be taken into account if the
* method {@link #getValue(double)} is invoked (rounding).
*/
public int getDecimals() {
return this.m_decimals;
}
/**
* Returns the factor a result of {@link #getValue(double)} had to be
* multiplied with if the real (unitless) value has to be calculated.
* <p>
*
* For performance reason (fast access) factor is public. This is against
* "safety by desing" so do never set this value.
* <p>
*
* @return the factor a result of {@link #getValue(double)} had to be
* multiplied with if the real (unitless) value has to be calculated.
*/
public double getFactor() {
return this.m_factor;
}
/**
* Returns the the value divided by this unit's factor, rounded to this unit's
* configured decimals and suffixed by the unit name.
* <p>
*
* @param value
* the value for the label.
*
* @return the the value divided by this unit's factor, rounded by this unit's
* configured decimals and suffixed by the unit name.
*
* @see #getUnitName()
* @see #getDecimals()
*
*/
public String getLabel(final double value) {
return new StringBuffer().append(this.round(value / this.m_factor)).append(" ").append(
this.m_unitName).toString();
}
/**
* Returns the next smaller unit to this one within this unit's
* {@link IUnitSystem}.
* <p>
*
* If this is already the smallest unit, this will be returned so add
* <code>unit == unit.getLowerUnit()</code> as the termination criteria in
* loops to search for the smallest unit (to avoid endless loops).
* <p>
*
* @return the next lower unit to this one within this unit's
* {@link IUnitSystem}.
*/
public AUnit getNexLowerUnit() {
return this.m_nexLowerUnit;
}
/**
* Returns the next greater unit to this one within this unit's
* {@link IUnitSystem}.
* <p>
*
* If this is already the greatest unit, this will be returned so add
* <code>unit == unit.getNextHigherUnit()</code> as the termination criteria
* in loops to search for the greatest unit (to avoid endless loops).
* <p>
*
* @return the next greater unit to this one within this unit's
* {@link IUnitSystem}.
*/
public AUnit getNextHigherUnit() {
return this.m_nextHigherUnit;
}
/**
* Retunrns the short unit name of this unit a result of
* {@link #getValue(double)} has to be related with to know the this result is
* displayed in a unit.
* <p>
*
* @return the short unit name of this unit a result of
* {@link #getValue(double)} has to be related with to know the this
* result is displayed in a unit.
* <p>
*/
public String getUnitName() {
return this.m_unitName;
}
/**
* Transforms the given absolute value into the represented unit value by
* dividing by the specific factor.
* <p>
*
* The result is rounded using the actual decimal setting.
* <p>
*
* @param value
* the value to represent in this unit.
*
* @return The value to display in this unit rounded using the internal
* decimals.
*/
public double getValue(final double value) {
return this.round(value / this.m_factor);
}
/**
* Internal rounding routine for {@link #getValue(double)}.
* <p>
*
* @param value
* the value to round.
* @return the given value rounded to the amount of decimals configured.
*/
private final double round(final double value) {
double tmp = Math.pow(10, this.m_decimals);
return (Math.floor(value * tmp + 0.5d)) / tmp;
}
/**
* Define how many decimals should be taken into account if the method
* {@link #getValue(double)} is invoked (rounding).
* <p>
*
* @param aftercomma
* the number of decimals that should be taken into account if the
* method {@link #getValue(double)} is invoked (rounding)
*/
public void setDecimals(final int aftercomma) {
if (aftercomma >= 0) {
this.m_decimals = aftercomma;
}
}
/**
* Returns the same as {@link #getUnitName()}, prefer calling this directly
* if desired.
* <p>
*
* @return the same as {@link #getUnitName()}, prefer calling this directly
* if desired.
*
*/
@Override
public String toString() {
return this.getUnitName();
}
}