Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.Serializable; /** * <p><code>IntRange</code> represents an inclusive range of <code>int</code>s.</p> * * @author Stephen Colebourne * @since 2.0 * @version $Id: IntRange.java 594398 2007-11-13 02:43:10Z bayard $ */ public final class IntRange extends Range implements Serializable { /** * Required for serialization support. * * @see java.io.Serializable */ private static final long serialVersionUID = 71849363892730L; /** * The minimum number in this range (inclusive). */ private final int min; /** * The maximum number in this range (inclusive). */ private final int max; /** * Cached output minObject (class is immutable). */ private transient Integer minObject = null; /** * Cached output maxObject (class is immutable). */ private transient Integer maxObject = null; /** * Cached output hashCode (class is immutable). */ private transient int hashCode = 0; /** * Cached output toString (class is immutable). */ private transient String toString = null; /** * <p>Constructs a new <code>IntRange</code> using the specified * number as both the minimum and maximum in this range.</p> * * @param number the number to use for this range */ public IntRange(int number) { super(); this.min = number; this.max = number; } /** * <p>Constructs a new <code>IntRange</code> using the specified * number as both the minimum and maximum in this range.</p> * * @param number the number to use for this range, must not be <code>null</code> * @throws IllegalArgumentException if the number is <code>null</code> */ public IntRange(Number number) { super(); if (number == null) { throw new IllegalArgumentException("The number must not be null"); } this.min = number.intValue(); this.max = number.intValue(); if (number instanceof Integer) { this.minObject = (Integer) number; this.maxObject = (Integer) number; } } /** * <p>Constructs a new <code>IntRange</code> with the specified * minimum and maximum numbers (both inclusive).</p> * * <p>The arguments may be passed in the order (min,max) or (max,min). The * getMinimum and getMaximum methods will return the correct values.</p> * * @param number1 first number that defines the edge of the range, inclusive * @param number2 second number that defines the edge of the range, inclusive */ public IntRange(int number1, int number2) { super(); if (number2 < number1) { this.min = number2; this.max = number1; } else { this.min = number1; this.max = number2; } } /** * <p>Constructs a new <code>IntRange</code> with the specified * minimum and maximum numbers (both inclusive).</p> * * <p>The arguments may be passed in the order (min,max) or (max,min). The * getMinimum and getMaximum methods will return the correct values.</p> * * @param number1 first number that defines the edge of the range, inclusive * @param number2 second number that defines the edge of the range, inclusive * @throws IllegalArgumentException if either number is <code>null</code> */ public IntRange(Number number1, Number number2) { super(); if (number1 == null || number2 == null) { throw new IllegalArgumentException("The numbers must not be null"); } int number1val = number1.intValue(); int number2val = number2.intValue(); if (number2val < number1val) { this.min = number2val; this.max = number1val; if (number2 instanceof Integer) { this.minObject = (Integer) number2; } if (number1 instanceof Integer) { this.maxObject = (Integer) number1; } } else { this.min = number1val; this.max = number2val; if (number1 instanceof Integer) { this.minObject = (Integer) number1; } if (number2 instanceof Integer) { this.maxObject = (Integer) number2; } } } // Accessors //-------------------------------------------------------------------- /** * <p>Returns the minimum number in this range.</p> * * @return the minimum number in this range */ public Number getMinimumNumber() { if (minObject == null) { minObject = new Integer(min); } return minObject; } /** * <p>Gets the minimum number in this range as a <code>long</code>.</p> * * @return the minimum number in this range */ public long getMinimumLong() { return min; } /** * <p>Gets the minimum number in this range as a <code>int</code>.</p> * * @return the minimum number in this range */ public int getMinimumInteger() { return min; } /** * <p>Gets the minimum number in this range as a <code>double</code>.</p> * * @return the minimum number in this range */ public double getMinimumDouble() { return min; } /** * <p>Gets the minimum number in this range as a <code>float</code>.</p> * * @return the minimum number in this range */ public float getMinimumFloat() { return min; } /** * <p>Returns the maximum number in this range.</p> * * @return the maximum number in this range */ public Number getMaximumNumber() { if (maxObject == null) { maxObject = new Integer(max); } return maxObject; } /** * <p>Gets the maximum number in this range as a <code>long</code>.</p> * * @return the maximum number in this range */ public long getMaximumLong() { return max; } /** * <p>Gets the maximum number in this range as a <code>int</code>.</p> * * @return the maximum number in this range */ public int getMaximumInteger() { return max; } /** * <p>Gets the maximum number in this range as a <code>double</code>.</p> * * @return the maximum number in this range */ public double getMaximumDouble() { return max; } /** * <p>Gets the maximum number in this range as a <code>float</code>.</p> * * @return the maximum number in this range */ public float getMaximumFloat() { return max; } // Tests //-------------------------------------------------------------------- /** * <p>Tests whether the specified <code>number</code> occurs within * this range using <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * @param number the number to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this range */ public boolean containsNumber(Number number) { if (number == null) { return false; } return containsInteger(number.intValue()); } /** * <p>Tests whether the specified <code>int</code> occurs within * this range using <code>int</code> comparison.</p> * * <p>This implementation overrides the superclass for performance as it is * the most common case.</p> * * @param value the int to test * @return <code>true</code> if the specified number occurs within this * range by <code>int</code> comparison */ public boolean containsInteger(int value) { return value >= min && value <= max; } // Range tests //-------------------------------------------------------------------- /** * <p>Tests whether the specified range occurs entirely within this range * using <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * @param range the range to test, may be <code>null</code> * @return <code>true</code> if the specified range occurs entirely within this range * @throws IllegalArgumentException if the range is not of this type */ public boolean containsRange(Range range) { if (range == null) { return false; } return containsInteger(range.getMinimumInteger()) && containsInteger(range.getMaximumInteger()); } /** * <p>Tests whether the specified range overlaps with this range * using <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * @param range the range to test, may be <code>null</code> * @return <code>true</code> if the specified range overlaps with this range */ public boolean overlapsRange(Range range) { if (range == null) { return false; } return range.containsInteger(min) || range.containsInteger(max) || containsInteger(range.getMinimumInteger()); } // Basics //-------------------------------------------------------------------- /** * <p>Compares this range to another object to test if they are equal.</p>. * * <p>To be equal, the class, minimum and maximum must be equal.</p> * * @param obj the reference object with which to compare * @return <code>true</code> if this object is equal */ public boolean equals(Object obj) { if (obj == this) { return true; } if (obj instanceof IntRange == false) { return false; } IntRange range = (IntRange) obj; return min == range.min && max == range.max; } /** * <p>Gets a hashCode for the range.</p> * * @return a hash code value for this object */ public int hashCode() { if (hashCode == 0) { hashCode = 17; hashCode = 37 * hashCode + getClass().hashCode(); hashCode = 37 * hashCode + min; hashCode = 37 * hashCode + max; } return hashCode; } /** * <p>Gets the range as a <code>String</code>.</p> * * <p>The format of the String is 'Range[<i>min</i>,<i>max</i>]'.</p> * * @return the <code>String</code> representation of this range */ public String toString() { if (toString == null) { StringBuffer buf = new StringBuffer(32); buf.append("Range["); buf.append(min); buf.append(','); buf.append(max); buf.append(']'); toString = buf.toString(); } return toString; } /** * <p>Returns an array containing all the integer values in the range.</p> * * @return the <code>int[]</code> representation of this range * @since 2.4 */ public int[] toArray() { int[] array = new int[max - min + 1]; for (int i = 0; i < array.length; i++) { array[i] = min + i; } return array; } } /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * <p><code>Range</code> represents a range of numbers of the same type.</p> * * <p>Specific subclasses hold the range values as different types. Each * subclass should be immutable and {@link java.io.Serializable Serializable} * if possible.</p> * * @author Stephen Colebourne * @since 2.0 * @version $Id: Range.java 437554 2006-08-28 06:21:41Z bayard $ */ abstract class Range { /** * <p>Constructs a new range.</p> */ public Range() { super(); } // Accessors //-------------------------------------------------------------------- /** * <p>Gets the minimum number in this range.</p> * * @return the minimum number in this range */ public abstract Number getMinimumNumber(); /** * <p>Gets the minimum number in this range as a <code>long</code>.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the minimum number in this range */ public long getMinimumLong() { return getMinimumNumber().longValue(); } /** * <p>Gets the minimum number in this range as a <code>int</code>.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the minimum number in this range */ public int getMinimumInteger() { return getMinimumNumber().intValue(); } /** * <p>Gets the minimum number in this range as a <code>double</code>.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the minimum number in this range */ public double getMinimumDouble() { return getMinimumNumber().doubleValue(); } /** * <p>Gets the minimum number in this range as a <code>float</code>.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the minimum number in this range */ public float getMinimumFloat() { return getMinimumNumber().floatValue(); } /** * <p>Gets the maximum number in this range.</p> * * @return the maximum number in this range */ public abstract Number getMaximumNumber(); /** * <p>Gets the maximum number in this range as a <code>long</code>.</p> * * <p>This implementation uses the {@link #getMaximumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the maximum number in this range */ public long getMaximumLong() { return getMaximumNumber().longValue(); } /** * <p>Gets the maximum number in this range as a <code>int</code>.</p> * * <p>This implementation uses the {@link #getMaximumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the maximum number in this range */ public int getMaximumInteger() { return getMaximumNumber().intValue(); } /** * <p>Gets the maximum number in this range as a <code>double</code>.</p> * * <p>This implementation uses the {@link #getMaximumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the maximum number in this range */ public double getMaximumDouble() { return getMaximumNumber().doubleValue(); } /** * <p>Gets the maximum number in this range as a <code>float</code>.</p> * * <p>This implementation uses the {@link #getMaximumNumber()} method. * Subclasses may be able to optimise this.</p> * * @return the maximum number in this range */ public float getMaximumFloat() { return getMaximumNumber().floatValue(); } // Include tests //-------------------------------------------------------------------- /** * <p>Tests whether the specified <code>Number</code> occurs within * this range.</p> * * <p>The exact comparison implementation varies by subclass. It is * intended that an <code>int</code> specific subclass will compare using * <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * @param number the number to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this range * @throws IllegalArgumentException if the <code>Number</code> cannot be compared */ public abstract boolean containsNumber(Number number); /** * <p>Tests whether the specified <code>Number</code> occurs within * this range using <code>long</code> comparison..</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation forwards to the {@link #containsLong(long)} method.</p> * * @param value the long to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this * range by <code>long</code> comparison */ public boolean containsLong(Number value) { if (value == null) { return false; } return containsLong(value.longValue()); } /** * <p>Tests whether the specified <code>long</code> occurs within * this range using <code>long</code> comparison.</p> * * <p>This implementation uses the {@link #getMinimumLong()} and * {@link #getMaximumLong()} methods and should be good for most uses.</p> * * @param value the long to test * @return <code>true</code> if the specified number occurs within this * range by <code>long</code> comparison */ public boolean containsLong(long value) { return value >= getMinimumLong() && value <= getMaximumLong(); } /** * <p>Tests whether the specified <code>Number</code> occurs within * this range using <code>int</code> comparison..</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation forwards to the {@link #containsInteger(int)} method.</p> * * @param value the integer to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this * range by <code>int</code> comparison */ public boolean containsInteger(Number value) { if (value == null) { return false; } return containsInteger(value.intValue()); } /** * <p>Tests whether the specified <code>int</code> occurs within * this range using <code>int</code> comparison.</p> * * <p>This implementation uses the {@link #getMinimumInteger()} and * {@link #getMaximumInteger()} methods and should be good for most uses.</p> * * @param value the int to test * @return <code>true</code> if the specified number occurs within this * range by <code>int</code> comparison */ public boolean containsInteger(int value) { return value >= getMinimumInteger() && value <= getMaximumInteger(); } /** * <p>Tests whether the specified <code>Number</code> occurs within * this range using <code>double</code> comparison..</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation forwards to the {@link #containsDouble(double)} method.</p> * * @param value the double to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this * range by <code>double</code> comparison */ public boolean containsDouble(Number value) { if (value == null) { return false; } return containsDouble(value.doubleValue()); } /** * <p>Tests whether the specified <code>double</code> occurs within * this range using <code>double</code> comparison.</p> * * <p>This implementation uses the {@link #getMinimumDouble()} and * {@link #getMaximumDouble()} methods and should be good for most uses.</p> * * @param value the double to test * @return <code>true</code> if the specified number occurs within this * range by <code>double</code> comparison */ public boolean containsDouble(double value) { int compareMin = compare(getMinimumDouble(), value); int compareMax = compare(getMaximumDouble(), value); return compareMin <= 0 && compareMax >= 0; } /** * <p>Tests whether the specified <code>Number</code> occurs within * this range using <code>float</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation forwards to the {@link #containsFloat(float)} method.</p> * * @param value the float to test, may be <code>null</code> * @return <code>true</code> if the specified number occurs within this * range by <code>float</code> comparison */ public boolean containsFloat(Number value) { if (value == null) { return false; } return containsFloat(value.floatValue()); } /** * <p>Tests whether the specified <code>float</code> occurs within * this range using <code>float</code> comparison.</p> * * <p>This implementation uses the {@link #getMinimumFloat()} and * {@link #getMaximumFloat()} methods and should be good for most uses.</p> * * @param value the float to test * @return <code>true</code> if the specified number occurs within this * range by <code>float</code> comparison */ public boolean containsFloat(float value) { int compareMin = compare(getMinimumFloat(), value); int compareMax = compare(getMaximumFloat(), value); return compareMin <= 0 && compareMax >= 0; } // Range tests //-------------------------------------------------------------------- /** * <p>Tests whether the specified range occurs entirely within this range.</p> * * <p>The exact comparison implementation varies by subclass. It is * intended that an <code>int</code> specific subclass will compare using * <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation uses the {@link #containsNumber(Number)} method. * Subclasses may be able to optimise this.</p> * * @param range the range to test, may be <code>null</code> * @return <code>true</code> if the specified range occurs entirely within * this range; otherwise, <code>false</code> * @throws IllegalArgumentException if the <code>Range</code> cannot be compared */ public boolean containsRange(Range range) { if (range == null) { return false; } return containsNumber(range.getMinimumNumber()) && containsNumber(range.getMaximumNumber()); } /** * <p>Tests whether the specified range overlaps with this range.</p> * * <p>The exact comparison implementation varies by subclass. It is * intended that an <code>int</code> specific subclass will compare using * <code>int</code> comparison.</p> * * <p><code>null</code> is handled and returns <code>false</code>.</p> * * <p>This implementation uses the {@link #containsNumber(Number)} and * {@link #containsRange(Range)} methods. * Subclasses may be able to optimise this.</p> * * @param range the range to test, may be <code>null</code> * @return <code>true</code> if the specified range overlaps with this * range; otherwise, <code>false</code> * @throws IllegalArgumentException if the <code>Range</code> cannot be compared */ public boolean overlapsRange(Range range) { if (range == null) { return false; } return range.containsNumber(getMinimumNumber()) || range.containsNumber(getMaximumNumber()) || containsNumber(range.getMinimumNumber()); } // Basics //-------------------------------------------------------------------- /** * <p>Compares this range to another object to test if they are equal.</p>. * * <p>To be equal, the class, minimum and maximum must be equal.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} and * {@link #getMaximumNumber()} methods. * Subclasses may be able to optimise this.</p> * * @param obj the reference object with which to compare * @return <code>true</code> if this object is equal */ public boolean equals(Object obj) { if (obj == this) { return true; } else if (obj == null || obj.getClass() != getClass()) { return false; } else { Range range = (Range) obj; return getMinimumNumber().equals(range.getMinimumNumber()) && getMaximumNumber().equals(range.getMaximumNumber()); } } /** * <p>Gets a hashCode for the range.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} and * {@link #getMaximumNumber()} methods. * Subclasses may be able to optimise this.</p> * * @return a hash code value for this object */ public int hashCode() { int result = 17; result = 37 * result + getClass().hashCode(); result = 37 * result + getMinimumNumber().hashCode(); result = 37 * result + getMaximumNumber().hashCode(); return result; } /** * <p>Gets the range as a <code>String</code>.</p> * * <p>The format of the String is 'Range[<i>min</i>,<i>max</i>]'.</p> * * <p>This implementation uses the {@link #getMinimumNumber()} and * {@link #getMaximumNumber()} methods. * Subclasses may be able to optimise this.</p> * * @return the <code>String</code> representation of this range */ public String toString() { StringBuffer buf = new StringBuffer(32); buf.append("Range["); buf.append(getMinimumNumber()); buf.append(','); buf.append(getMaximumNumber()); buf.append(']'); return buf.toString(); } /** * <p>Compares two <code>doubles</code> for order.</p> * * <p>This method is more comprehensive than the standard Java greater * than, less than and equals operators.</p> * <ul> * <li>It returns <code>-1</code> if the first value is less than the second.</li> * <li>It returns <code>+1</code> if the first value is greater than the second.</li> * <li>It returns <code>0</code> if the values are equal.</li> * </ul> * * <p> * The ordering is as follows, largest to smallest: * <ul> * <li>NaN * <li>Positive infinity * <li>Maximum double * <li>Normal positive numbers * <li>+0.0 * <li>-0.0 * <li>Normal negative numbers * <li>Minimum double (<code>-Double.MAX_VALUE</code>) * <li>Negative infinity * </ul> * </p> * * <p>Comparing <code>NaN</code> with <code>NaN</code> will * return <code>0</code>.</p> * * @param lhs the first <code>double</code> * @param rhs the second <code>double</code> * @return <code>-1</code> if lhs is less, <code>+1</code> if greater, * <code>0</code> if equal to rhs */ public static int compare(double lhs, double rhs) { if (lhs < rhs) { return -1; } if (lhs > rhs) { return +1; } // Need to compare bits to handle 0.0 == -0.0 being true // compare should put -0.0 < +0.0 // Two NaNs are also == for compare purposes // where NaN == NaN is false long lhsBits = Double.doubleToLongBits(lhs); long rhsBits = Double.doubleToLongBits(rhs); if (lhsBits == rhsBits) { return 0; } // Something exotic! A comparison to NaN or 0.0 vs -0.0 // Fortunately NaN's long is > than everything else // Also negzeros bits < poszero // NAN: 9221120237041090560 // MAX: 9218868437227405311 // NEGZERO: -9223372036854775808 if (lhsBits < rhsBits) { return -1; } else { return +1; } } /** * <p>Compares two floats for order.</p> * * <p>This method is more comprehensive than the standard Java greater than, * less than and equals operators.</p> * <ul> * <li>It returns <code>-1</code> if the first value is less than the second. * <li>It returns <code>+1</code> if the first value is greater than the second. * <li>It returns <code>0</code> if the values are equal. * </ul> * * <p> The ordering is as follows, largest to smallest: * <ul> * <li>NaN * <li>Positive infinity * <li>Maximum float * <li>Normal positive numbers * <li>+0.0 * <li>-0.0 * <li>Normal negative numbers * <li>Minimum float (<code>-Float.MAX_VALUE</code>) * <li>Negative infinity * </ul> * * <p>Comparing <code>NaN</code> with <code>NaN</code> will return * <code>0</code>.</p> * * @param lhs the first <code>float</code> * @param rhs the second <code>float</code> * @return <code>-1</code> if lhs is less, <code>+1</code> if greater, * <code>0</code> if equal to rhs */ public static int compare(float lhs, float rhs) { if (lhs < rhs) { return -1; } if (lhs > rhs) { return +1; } //Need to compare bits to handle 0.0 == -0.0 being true // compare should put -0.0 < +0.0 // Two NaNs are also == for compare purposes // where NaN == NaN is false int lhsBits = Float.floatToIntBits(lhs); int rhsBits = Float.floatToIntBits(rhs); if (lhsBits == rhsBits) { return 0; } //Something exotic! A comparison to NaN or 0.0 vs -0.0 //Fortunately NaN's int is > than everything else //Also negzeros bits < poszero //NAN: 2143289344 //MAX: 2139095039 //NEGZERO: -2147483648 if (lhsBits < rhsBits) { return -1; } else { return +1; } } }