/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* ----------
* Range.java
* ----------
* (C) Copyright 2002-2008, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): Chuanhao Chiu;
* Bill Kelemen;
* Nicolas Brodu;
* Sergei Ivanov;
*
* Changes (from 23-Jun-2001)
* --------------------------
* 22-Apr-2002 : Version 1, loosely based by code by Bill Kelemen (DG);
* 30-Apr-2002 : Added getLength() and getCentralValue() methods. Changed
* argument check in constructor (DG);
* 13-Jun-2002 : Added contains(double) method (DG);
* 22-Aug-2002 : Added fix to combine method where both ranges are null, thanks
* to Chuanhao Chiu for reporting and fixing this (DG);
* 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
* 26-Mar-2003 : Implemented Serializable (DG);
* 14-Aug-2003 : Added equals() method (DG);
* 27-Aug-2003 : Added toString() method (BK);
* 11-Sep-2003 : Added Clone Support (NB);
* 23-Sep-2003 : Fixed Checkstyle issues (DG);
* 25-Sep-2003 : Oops, Range immutable, clone not necessary (NB);
* 05-May-2004 : Added constrain() and intersects() methods (DG);
* 18-May-2004 : Added expand() method (DG);
* ------------- JFreeChart 1.0.x ---------------------------------------------
* 11-Jan-2006 : Added new method expandToInclude(Range, double) (DG);
* 18-Dec-2007 : New methods intersects(Range) and scale(...) thanks to Sergei
* Ivanov (DG);
*
*/
package org.jfree.data;
import java.io.Serializable;
/**
* Represents an immutable range of values.
*/
public strictfp class Range implements Serializable {
/** For serialization. */
private static final long serialVersionUID = -906333695431863380L;
/** The lower bound of the range. */
private double lower;
/** The upper bound of the range. */
private double upper;
/**
* Creates a new range.
*
* @param lower the lower bound (must be <= upper bound).
* @param upper the upper bound (must be >= lower bound).
*/
public Range(double lower, double upper) {
if (lower > upper) {
String msg = "Range(double, double): require lower (" + lower
+ ") <= upper (" + upper + ").";
throw new IllegalArgumentException(msg);
}
this.lower = lower;
this.upper = upper;
}
/**
* Returns the lower bound for the range.
*
* @return The lower bound.
*/
public double getLowerBound() {
return this.lower;
}
/**
* Returns the upper bound for the range.
*
* @return The upper bound.
*/
public double getUpperBound() {
return this.upper;
}
/**
* Returns the length of the range.
*
* @return The length.
*/
public double getLength() {
return this.upper - this.lower;
}
/**
* Returns the central value for the range.
*
* @return The central value.
*/
public double getCentralValue() {
return this.lower / 2.0 + this.upper / 2.0;
}
/**
* Returns <code>true</code> if the range contains the specified value and
* <code>false</code> otherwise.
*
* @param value the value to lookup.
*
* @return <code>true</code> if the range contains the specified value.
*/
public boolean contains(double value) {
return (value >= this.lower && value <= this.upper);
}
/**
* Returns <code>true</code> if the range intersects with the specified
* range, and <code>false</code> otherwise.
*
* @param b0 the lower bound (should be <= b1).
* @param b1 the upper bound (should be >= b0).
*
* @return A boolean.
*/
public boolean intersects(double b0, double b1) {
if (b0 <= this.lower) {
return (b1 > this.lower);
}
else {
return (b0 < this.upper && b1 >= b0);
}
}
/**
* Returns <code>true</code> if the range intersects with the specified
* range, and <code>false</code> otherwise.
*
* @param range another range (<code>null</code> not permitted).
*
* @return A boolean.
*
* @since 1.0.9
*/
public boolean intersects(Range range) {
return intersects(range.getLowerBound(), range.getUpperBound());
}
/**
* Returns the value within the range that is closest to the specified
* value.
*
* @param value the value.
*
* @return The constrained value.
*/
public double constrain(double value) {
double result = value;
if (!contains(value)) {
if (value > this.upper) {
result = this.upper;
}
else if (value < this.lower) {
result = this.lower;
}
}
return result;
}
/**
* Creates a new range by combining two existing ranges.
* <P>
* Note that:
* <ul>
* <li>either range can be <code>null</code>, in which case the other
* range is returned;</li>
* <li>if both ranges are <code>null</code> the return value is
* <code>null</code>.</li>
* </ul>
*
* @param range1 the first range (<code>null</code> permitted).
* @param range2 the second range (<code>null</code> permitted).
*
* @return A new range (possibly <code>null</code>).
*/
public static Range combine(Range range1, Range range2) {
if (range1 == null) {
return range2;
}
else {
if (range2 == null) {
return range1;
}
else {
double l = Math.min(range1.getLowerBound(),
range2.getLowerBound());
double u = Math.max(range1.getUpperBound(),
range2.getUpperBound());
return new Range(l, u);
}
}
}
/**
* Returns a range that includes all the values in the specified
* <code>range</code> AND the specified <code>value</code>.
*
* @param range the range (<code>null</code> permitted).
* @param value the value that must be included.
*
* @return A range.
*
* @since 1.0.1
*/
public static Range expandToInclude(Range range, double value) {
if (range == null) {
return new Range(value, value);
}
if (value < range.getLowerBound()) {
return new Range(value, range.getUpperBound());
}
else if (value > range.getUpperBound()) {
return new Range(range.getLowerBound(), value);
}
else {
return range;
}
}
/**
* Creates a new range by adding margins to an existing range.
*
* @param range the range (<code>null</code> not permitted).
* @param lowerMargin the lower margin (expressed as a percentage of the
* range length).
* @param upperMargin the upper margin (expressed as a percentage of the
* range length).
*
* @return The expanded range.
*/
public static Range expand(Range range,
double lowerMargin, double upperMargin) {
if (range == null) {
throw new IllegalArgumentException("Null 'range' argument.");
}
double length = range.getLength();
double lower = range.getLowerBound() - length * lowerMargin;
double upper = range.getUpperBound() + length * upperMargin;
if (lower > upper) {
lower = lower / 2.0 + upper / 2.0;
upper = lower;
}
return new Range(lower, upper);
}
/**
* Shifts the range by the specified amount.
*
* @param base the base range (<code>null</code> not permitted).
* @param delta the shift amount.
*
* @return A new range.
*/
public static Range shift(Range base, double delta) {
return shift(base, delta, false);
}
/**
* Shifts the range by the specified amount.
*
* @param base the base range (<code>null</code> not permitted).
* @param delta the shift amount.
* @param allowZeroCrossing a flag that determines whether or not the
* bounds of the range are allowed to cross
* zero after adjustment.
*
* @return A new range.
*/
public static Range shift(Range base, double delta,
boolean allowZeroCrossing) {
if (base == null) {
throw new IllegalArgumentException("Null 'base' argument.");
}
if (allowZeroCrossing) {
return new Range(base.getLowerBound() + delta,
base.getUpperBound() + delta);
}
else {
return new Range(shiftWithNoZeroCrossing(base.getLowerBound(),
delta), shiftWithNoZeroCrossing(base.getUpperBound(),
delta));
}
}
/**
* Returns the given <code>value</code> adjusted by <code>delta</code> but
* with a check to prevent the result from crossing <code>0.0</code>.
*
* @param value the value.
* @param delta the adjustment.
*
* @return The adjusted value.
*/
private static double shiftWithNoZeroCrossing(double value, double delta) {
if (value > 0.0) {
return Math.max(value + delta, 0.0);
}
else if (value < 0.0) {
return Math.min(value + delta, 0.0);
}
else {
return value + delta;
}
}
/**
* Scales the range by the specified factor.
*
* @param base the base range (<code>null</code> not permitted).
* @param factor the scaling factor (must be non-negative).
*
* @return A new range.
*
* @since 1.0.9
*/
public static Range scale(Range base, double factor) {
if (base == null) {
throw new IllegalArgumentException("Null 'base' argument.");
}
if (factor < 0) {
throw new IllegalArgumentException("Negative 'factor' argument.");
}
return new Range(base.getLowerBound() * factor,
base.getUpperBound() * factor);
}
/**
* Tests this object for equality with an arbitrary object.
*
* @param obj the object to test against (<code>null</code> permitted).
*
* @return A boolean.
*/
public boolean equals(Object obj) {
if (!(obj instanceof Range)) {
return false;
}
Range range = (Range) obj;
if (!(this.lower == range.lower)) {
return false;
}
if (!(this.upper == range.upper)) {
return false;
}
return true;
}
/**
* Returns a hash code.
*
* @return A hash code.
*/
public int hashCode() {
int result;
long temp;
temp = Double.doubleToLongBits(this.lower);
result = (int) (temp ^ (temp >>> 32));
temp = Double.doubleToLongBits(this.upper);
result = 29 * result + (int) (temp ^ (temp >>> 32));
return result;
}
/**
* Returns a string representation of this Range.
*
* @return A String "Range[lower,upper]" where lower=lower range and
* upper=upper range.
*/
public String toString() {
return ("Range[" + this.lower + "," + this.upper + "]");
}
}
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