001: /*
002: * Licensed to the Apache Software Foundation (ASF) under one or more
003: * contributor license agreements. See the NOTICE file distributed with
004: * this work for additional information regarding copyright ownership.
005: * The ASF licenses this file to You under the Apache License, Version 2.0
006: * (the "License"); you may not use this file except in compliance with
007: * the License. You may obtain a copy of the License at
008: *
009: * http://www.apache.org/licenses/LICENSE-2.0
010: *
011: * Unless required by applicable law or agreed to in writing, software
012: * distributed under the License is distributed on an "AS IS" BASIS,
013: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014: * See the License for the specific language governing permissions and
015: * limitations under the License.
016: */
017: package org.apache.commons.lang.math;
018:
019: import java.io.Serializable;
020:
021: /**
022: * <p><code>NumberRange</code> represents an inclusive range of
023: * {@link java.lang.Number} objects of the same type.</p>
024: *
025: * @author <a href="mailto:chrise@esha.com">Christopher Elkins</a>
026: * @author Stephen Colebourne
027: * @since 2.0 (previously in org.apache.commons.lang)
028: * @version $Id: NumberRange.java 437554 2006-08-28 06:21:41Z bayard $
029: */
030: public final class NumberRange extends Range implements Serializable {
031:
032: /**
033: * Required for serialization support.
034: *
035: * @see java.io.Serializable
036: */
037: private static final long serialVersionUID = 71849363892710L;
038:
039: /**
040: * The minimum number in this range.
041: */
042: private final Number min;
043: /**
044: * The maximum number in this range.
045: */
046: private final Number max;
047:
048: /**
049: * Cached output hashCode (class is immutable).
050: */
051: private transient int hashCode = 0;
052: /**
053: * Cached output toString (class is immutable).
054: */
055: private transient String toString = null;
056:
057: /**
058: * <p>Constructs a new <code>NumberRange</code> using the specified
059: * number as both the minimum and maximum in this range.</p>
060: *
061: * @param num the number to use for this range
062: * @throws IllegalArgumentException if the number is <code>null</code>
063: * @throws IllegalArgumentException if the number doesn't implement <code>Comparable</code>
064: * @throws IllegalArgumentException if the number is <code>Double.NaN</code> or <code>Float.NaN</code>
065: */
066: public NumberRange(Number num) {
067: if (num == null) {
068: throw new IllegalArgumentException(
069: "The number must not be null");
070: }
071: if (num instanceof Comparable == false) {
072: throw new IllegalArgumentException(
073: "The number must implement Comparable");
074: }
075: if (num instanceof Double && ((Double) num).isNaN()) {
076: throw new IllegalArgumentException(
077: "The number must not be NaN");
078: }
079: if (num instanceof Float && ((Float) num).isNaN()) {
080: throw new IllegalArgumentException(
081: "The number must not be NaN");
082: }
083:
084: this .min = num;
085: this .max = num;
086: }
087:
088: /**
089: * <p>Constructs a new <code>NumberRange</code> with the specified
090: * minimum and maximum numbers (both inclusive).</p>
091: *
092: * <p>The arguments may be passed in the order (min,max) or (max,min). The
093: * {@link #getMinimumNumber()} and {@link #getMaximumNumber()} methods will return the
094: * correct value.</p>
095: *
096: * <p>This constructor is designed to be used with two <code>Number</code>
097: * objects of the same type. If two objects of different types are passed in,
098: * an exception is thrown.</p>
099: *
100: * @param num1 first number that defines the edge of the range, inclusive
101: * @param num2 second number that defines the edge of the range, inclusive
102: * @throws IllegalArgumentException if either number is <code>null</code>
103: * @throws IllegalArgumentException if the numbers are of different types
104: * @throws IllegalArgumentException if the numbers don't implement <code>Comparable</code>
105: */
106: public NumberRange(Number num1, Number num2) {
107: if (num1 == null || num2 == null) {
108: throw new IllegalArgumentException(
109: "The numbers must not be null");
110: }
111: if (num1.getClass() != num2.getClass()) {
112: throw new IllegalArgumentException(
113: "The numbers must be of the same type");
114: }
115: if (num1 instanceof Comparable == false) {
116: throw new IllegalArgumentException(
117: "The numbers must implement Comparable");
118: }
119: if (num1 instanceof Double) {
120: if (((Double) num1).isNaN() || ((Double) num2).isNaN()) {
121: throw new IllegalArgumentException(
122: "The number must not be NaN");
123: }
124: } else if (num1 instanceof Float) {
125: if (((Float) num1).isNaN() || ((Float) num2).isNaN()) {
126: throw new IllegalArgumentException(
127: "The number must not be NaN");
128: }
129: }
130:
131: int compare = ((Comparable) num1).compareTo(num2);
132: if (compare == 0) {
133: this .min = num1;
134: this .max = num1;
135: } else if (compare > 0) {
136: this .min = num2;
137: this .max = num1;
138: } else {
139: this .min = num1;
140: this .max = num2;
141: }
142: }
143:
144: // Accessors
145: //--------------------------------------------------------------------
146:
147: /**
148: * <p>Returns the minimum number in this range.</p>
149: *
150: * @return the minimum number in this range
151: */
152: public Number getMinimumNumber() {
153: return min;
154: }
155:
156: /**
157: * <p>Returns the maximum number in this range.</p>
158: *
159: * @return the maximum number in this range
160: */
161: public Number getMaximumNumber() {
162: return max;
163: }
164:
165: // Tests
166: //--------------------------------------------------------------------
167:
168: /**
169: * <p>Tests whether the specified <code>number</code> occurs within
170: * this range.</p>
171: *
172: * <p><code>null</code> is handled and returns <code>false</code>.</p>
173: *
174: * @param number the number to test, may be <code>null</code>
175: * @return <code>true</code> if the specified number occurs within this range
176: * @throws IllegalArgumentException if the number is of a different type to the range
177: */
178: public boolean containsNumber(Number number) {
179: if (number == null) {
180: return false;
181: }
182: if (number.getClass() != min.getClass()) {
183: throw new IllegalArgumentException(
184: "The number must be of the same type as the range numbers");
185: }
186: int compareMin = ((Comparable) min).compareTo(number);
187: int compareMax = ((Comparable) max).compareTo(number);
188: return compareMin <= 0 && compareMax >= 0;
189: }
190:
191: // Range tests
192: //--------------------------------------------------------------------
193: // use Range implementations
194:
195: // Basics
196: //--------------------------------------------------------------------
197:
198: /**
199: * <p>Compares this range to another object to test if they are equal.</p>.
200: *
201: * <p>To be equal, the class, minimum and maximum must be equal.</p>
202: *
203: * @param obj the reference object with which to compare
204: * @return <code>true</code> if this object is equal
205: */
206: public boolean equals(Object obj) {
207: if (obj == this ) {
208: return true;
209: }
210: if (obj instanceof NumberRange == false) {
211: return false;
212: }
213: NumberRange range = (NumberRange) obj;
214: return min.equals(range.min) && max.equals(range.max);
215: }
216:
217: /**
218: * <p>Gets a hashCode for the range.</p>
219: *
220: * @return a hash code value for this object
221: */
222: public int hashCode() {
223: if (hashCode == 0) {
224: hashCode = 17;
225: hashCode = 37 * hashCode + getClass().hashCode();
226: hashCode = 37 * hashCode + min.hashCode();
227: hashCode = 37 * hashCode + max.hashCode();
228: }
229: return hashCode;
230: }
231:
232: /**
233: * <p>Gets the range as a <code>String</code>.</p>
234: *
235: * <p>The format of the String is 'Range[<i>min</i>,<i>max</i>]'.</p>
236: *
237: * @return the <code>String</code> representation of this range
238: */
239: public String toString() {
240: if (toString == null) {
241: StringBuffer buf = new StringBuffer(32);
242: buf.append("Range[");
243: buf.append(min);
244: buf.append(',');
245: buf.append(max);
246: buf.append(']');
247: toString = buf.toString();
248: }
249: return toString;
250: }
251:
252: }
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